[syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove

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* [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
@ 2026-10-11 17:32 syzbot
  2026-10-12  5:11 ` Hillf Danton
                   ` (8 more replies)
  0 siblings, 9 replies; 20+ messages in thread
From: syzbot @ 2026-10-11 17:32 UTC (permalink / raw)
  To: hch, justin.tee, kch, linux-kernel, linux-nvme,
	nareshgottumukkala83, paul.ely, sagi, syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d24cfbd75fba/disk-a5ebb762.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d0874c703893/vmlinux-a5ebb762.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2a424fa32a7b/bzImage-a5ebb762.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c98b21427617af7f547a@syzkaller.appspotmail.com

nvmet_tcp: enabling port 1 (127.0.0.1:4420)
 non-slab/vmalloc memory
list_del corruption. prev->next should be ffff88802af3b020, but was 0000000000000000. (prev=ffffffff9aecd340)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:64!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 5680 Comm: syz-executor403 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 ab ea 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 6c b1 58 fd 49 8b 17 48 c7 c7 40 71 cc 8b 48 89 de 4c 89 f9 e8 a7 7a 4c fc 90 <0f> 0b 4c 89 f7 e8 7c ea 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 3d
RSP: 0018:ffffc90004cdfc30 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff88802af3b020 RCX: 7d3c36a647dfae00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000201 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed101708490b R12: 1ffffffff35d9a68
R13: dffffc0000000000 R14: ffffffff85f7f740 R15: ffffffff9aecd340
FS:  0000555594721400(0000) GS:ffff8881249bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555594721340 CR3: 0000000038dd8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:140 [inline]
 __list_del_entry include/linux/list.h:261 [inline]
 list_del include/linux/list.h:275 [inline]
 nvmet_fc_portentry_unbind drivers/nvme/target/fc.c:1281 [inline]
 nvmet_fc_remove_port+0x16b/0x320 drivers/nvme/target/fc.c:2927
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5678
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5748
 __do_sys_unlinkat fs/namei.c:5777 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5769
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0ad400d8b9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe650d4178 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 0000200000000780 RCX: 00007f0ad400d8b9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: 00000000ffffff9c
RBP: 00000000000f4240 R08: 0000000000000009 R09: 0000000000000009
R10: 0000000000000009 R11: 0000000000000246 R12: 0000000000014e22
R13: 00007ffe650d418c R14: 00007ffe650d41a0 R15: 00007ffe650d4190
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 ab ea 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 6c b1 58 fd 49 8b 17 48 c7 c7 40 71 cc 8b 48 89 de 4c 89 f9 e8 a7 7a 4c fc 90 <0f> 0b 4c 89 f7 e8 7c ea 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 3d
RSP: 0018:ffffc90004cdfc30 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff88802af3b020 RCX: 7d3c36a647dfae00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000201 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed101708490b R12: 1ffffffff35d9a68
R13: dffffc0000000000 R14: ffffffff85f7f740 R15: ffffffff9aecd340
FS:  0000555594721400(0000) GS:ffff8881249bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555594721340 CR3: 0000000038dd8000 CR4: 00000000003526f0


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-11 17:32 [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port syzbot
@ 2026-10-12  5:11 ` Hillf Danton
  2026-10-12  5:50   ` syzbot
  2026-10-12  7:58 ` Hillf Danton
                   ` (7 subsequent siblings)
  8 siblings, 1 reply; 20+ messages in thread
From: Hillf Danton @ 2026-10-12  5:11 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

> Date: Sun, 11 Oct 2026 10:32:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

#syz test

--- x/drivers/nvme/target/fc.c
+++ y/drivers/nvme/target/fc.c
@@ -1278,7 +1278,6 @@ nvmet_fc_portentry_unbind(struct nvmet_f
 		nvmet_fc_tgtport_put(pe->tgtport);
 		pe->tgtport->pe = NULL;
 	}
-	list_del(&pe->pe_list);
 	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 }
 
@@ -2922,6 +2921,7 @@ nvmet_fc_remove_port(struct nvmet_port *
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 	if (pe->tgtport && nvmet_fc_tgtport_get(pe->tgtport))
 		tgtport = pe->tgtport;
+	list_del(&pe->pe_list);
 	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 
 	nvmet_fc_portentry_unbind(pe);
--

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-12  5:11 ` Hillf Danton
@ 2026-10-12  5:50   ` syzbot
  0 siblings, 0 replies; 20+ messages in thread
From: syzbot @ 2026-10-12  5:50 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: corrupted list in nvmet_fc_remove_port

 non-slab/vmalloc memory
list_del corruption. prev->next should be ffff8880387ec820, but was 0000000000000000. (prev=ffffffff9aecd340)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:64!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6847 Comm: syz.0.45 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 8b f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 4c bf 58 fd 49 8b 17 48 c7 c7 40 6e cc 8b 48 89 de 4c 89 f9 e8 27 88 4c fc 90 <0f> 0b 4c 89 f7 e8 5c f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 1d
RSP: 0018:ffffc90004f8fc30 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff8880387ec820 RCX: 4b2bacb912474a00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed101708490b R12: 1ffffffff35d9a68
R13: dffffc0000000000 R14: ffffffff85f7e800 R15: ffffffff9aecd340
FS:  00007f415b0fd6c0(0000) GS:ffff8881249bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa587c4b8c0 CR3: 0000000037614000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:140 [inline]
 __list_del_entry include/linux/list.h:261 [inline]
 list_del include/linux/list.h:275 [inline]
 nvmet_fc_remove_port+0xbc/0x340 drivers/nvme/target/fc.c:2924
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5678
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5748
 __do_sys_unlinkat fs/namei.c:5777 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5769
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f415babe1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f415b0fd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007f415bd46090 RCX: 00007f415babe1d9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: ffffffffffffff9c
RBP: 00007f415bb55888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f415bd46128 R14: 00007f415bd46090 R15: 00007ffda341e7e8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 8b f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 4c bf 58 fd 49 8b 17 48 c7 c7 40 6e cc 8b 48 89 de 4c 89 f9 e8 27 88 4c fc 90 <0f> 0b 4c 89 f7 e8 5c f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 1d
RSP: 0018:ffffc90004f8fc30 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff8880387ec820 RCX: 4b2bacb912474a00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed101708490b R12: 1ffffffff35d9a68
R13: dffffc0000000000 R14: ffffffff85f7e800 R15: ffffffff9aecd340
FS:  00007f415b0fd6c0(0000) GS:ffff8881249bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa587c4b8c0 CR3: 0000000037614000 CR4: 00000000003526f0


Tested on:

commit:         24a19b95 Linux 7.3-rc7
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=160b540d580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1493540d580000


^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-11 17:32 [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port syzbot
  2026-10-12  5:11 ` Hillf Danton
@ 2026-10-12  7:58 ` Hillf Danton
  2026-10-12  8:25   ` syzbot
  2026-10-12 10:33 ` Hillf Danton
                   ` (6 subsequent siblings)
  8 siblings, 1 reply; 20+ messages in thread
From: Hillf Danton @ 2026-10-12  7:58 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

> Date: Sun, 11 Oct 2026 10:32:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

#syz test

--- x/drivers/nvme/target/fc.c
+++ y/drivers/nvme/target/fc.c
@@ -1273,7 +1273,14 @@ nvmet_fc_portentry_unbind(struct nvmet_f
 {
 	unsigned long flags;
 
+	if (!pe->port)
+		return;
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	if (!pe->port) {
+		spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+		return;
+	}
+	pe->port = NULL;
 	if (pe->tgtport) {
 		nvmet_fc_tgtport_put(pe->tgtport);
 		pe->tgtport->pe = NULL;
--

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-12  7:58 ` Hillf Danton
@ 2026-10-12  8:25   ` syzbot
  0 siblings, 0 replies; 20+ messages in thread
From: syzbot @ 2026-10-12  8:25 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: corrupted list in nvmet_fc_remove_port

 non-slab/vmalloc memory
list_del corruption. prev->next should be ffff88805f6be020, but was 0000000000000000. (prev=ffffffff9aecd340)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:64!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6706 Comm: syz.1.55 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 8b f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 4c bf 58 fd 49 8b 17 48 c7 c7 40 6e cc 8b 48 89 de 4c 89 f9 e8 27 88 4c fc 90 <0f> 0b 4c 89 f7 e8 5c f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 1d
RSP: 0018:ffffc90005077c38 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff88805f6be020 RCX: 3022935dcdf04700
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000201 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed101708490b R12: 1ffffffff35d9a68
R13: dffffc0000000000 R14: ffffffff85f7e840 R15: ffffffff9aecd340
FS:  00007f556375d6c0(0000) GS:ffff8881249bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcf66ae41d8 CR3: 0000000035112000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:140 [inline]
 __list_del_entry include/linux/list.h:261 [inline]
 list_del include/linux/list.h:275 [inline]
 nvmet_fc_portentry_unbind drivers/nvme/target/fc.c:1288 [inline]
 nvmet_fc_remove_port+0x1fb/0x380 drivers/nvme/target/fc.c:2934
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5678
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5748
 __do_sys_unlinkat fs/namei.c:5777 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5769
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f556411e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f556375d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007f55643a6090 RCX: 00007f556411e1d9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: ffffffffffffff9c
RBP: 00007f55641b5888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f55643a6128 R14: 00007f55643a6090 R15: 00007ffde0760588
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 8b f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 4c bf 58 fd 49 8b 17 48 c7 c7 40 6e cc 8b 48 89 de 4c 89 f9 e8 27 88 4c fc 90 <0f> 0b 4c 89 f7 e8 5c f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 1d
RSP: 0018:ffffc90005077c38 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff88805f6be020 RCX: 3022935dcdf04700
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000201 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed101708490b R12: 1ffffffff35d9a68
R13: dffffc0000000000 R14: ffffffff85f7e840 R15: ffffffff9aecd340
FS:  00007f556375d6c0(0000) GS:ffff8881249bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcf66c6f040 CR3: 0000000035112000 CR4: 00000000003526f0


Tested on:

commit:         24a19b95 Linux 7.3-rc7
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17e825d1580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12c690a5580000


^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-11 17:32 [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port syzbot
  2026-10-12  5:11 ` Hillf Danton
  2026-10-12  7:58 ` Hillf Danton
@ 2026-10-12 10:33 ` Hillf Danton
  2026-10-12 11:01   ` syzbot
  2026-10-12 12:41 ` Hillf Danton
                   ` (5 subsequent siblings)
  8 siblings, 1 reply; 20+ messages in thread
From: Hillf Danton @ 2026-10-12 10:33 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

> Date: Sun, 11 Oct 2026 10:32:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

#syz test

--- x/drivers/nvme/target/fc.c
+++ y/drivers/nvme/target/fc.c
@@ -2915,23 +2915,26 @@ nvmet_fc_add_port(struct nvmet_port *por
 static void
 nvmet_fc_remove_port(struct nvmet_port *port)
 {
-	struct nvmet_fc_port_entry *pe = port->priv;
+	struct nvmet_fc_port_entry *pe;
 	struct nvmet_fc_tgtport *tgtport = NULL;
 	unsigned long flags;
 
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
-	if (pe->tgtport && nvmet_fc_tgtport_get(pe->tgtport))
+	pe = port->priv;
+	port->priv = NULL;
+	if (pe && pe->tgtport && nvmet_fc_tgtport_get(pe->tgtport))
 		tgtport = pe->tgtport;
 	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 
-	nvmet_fc_portentry_unbind(pe);
-
 	if (tgtport) {
 		/* terminate any outstanding associations */
 		__nvmet_fc_free_assocs(tgtport);
 		nvmet_fc_tgtport_put(tgtport);
 	}
 
+	if (!pe)
+		return;
+	nvmet_fc_portentry_unbind(pe);
 	kfree(pe);
 }
 
--

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-12 10:33 ` Hillf Danton
@ 2026-10-12 11:01   ` syzbot
  0 siblings, 0 replies; 20+ messages in thread
From: syzbot @ 2026-10-12 11:01 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: user-memory-access Read in nvmet_fc_tgt_a_get

=========
==================================================================
BUG: KASAN: user-memory-access in instrument_atomic_read include/linux/instrumented.h:82 [inline]
BUG: KASAN: user-memory-access in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: user-memory-access in refcount_read include/linux/refcount.h:170 [inline]
BUG: KASAN: user-memory-access in __refcount_add_not_zero include/linux/refcount.h:176 [inline]
BUG: KASAN: user-memory-access in __refcount_inc_not_zero include/linux/refcount.h:317 [inline]
BUG: KASAN: user-memory-access in refcount_inc_not_zero include/linux/refcount.h:335 [inline]
BUG: KASAN: user-memory-access in kref_get_unless_zero include/linux/kref.h:133 [inline]
BUG: KASAN: user-memory-access in nvmet_fc_tgt_a_get+0x82/0x1d0 drivers/nvme/target/fc.c:1201
Read of size 4 at addr 000000000008c617 by task syz.1.88/6756

CPU: 0 UID: 0 PID: 6756 Comm: syz.1.88 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read include/linux/instrumented.h:82 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 refcount_read include/linux/refcount.h:170 [inline]
 __refcount_add_not_zero include/linux/refcount.h:176 [inline]
 __refcount_inc_not_zero include/linux/refcount.h:317 [inline]
 refcount_inc_not_zero include/linux/refcount.h:335 [inline]
 kref_get_unless_zero include/linux/kref.h:133 [inline]
 nvmet_fc_tgt_a_get+0x82/0x1d0 drivers/nvme/target/fc.c:1201
 __nvmet_fc_free_assocs+0x10c/0x380 drivers/nvme/target/fc.c:1480
 nvmet_fc_remove_port+0xc5/0x350 drivers/nvme/target/fc.c:2931
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5678
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5748
 __do_sys_unlinkat fs/namei.c:5777 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5769
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd82566e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd824cad028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007fd8258f6090 RCX: 00007fd82566e1d9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: ffffffffffffff9c
RBP: 00007fd825705888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd8258f6128 R14: 00007fd8258f6090 R15: 00007ffe18669a38
 </TASK>
==================================================================


Tested on:

commit:         24a19b95 Linux 7.3-rc7
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1710023e580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1432149c580000


^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-11 17:32 [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port syzbot
                   ` (2 preceding siblings ...)
  2026-10-12 10:33 ` Hillf Danton
@ 2026-10-12 12:41 ` Hillf Danton
  2026-10-12 13:11   ` syzbot
  2026-10-17  2:09 ` Hillf Danton
                   ` (4 subsequent siblings)
  8 siblings, 1 reply; 20+ messages in thread
From: Hillf Danton @ 2026-10-12 12:41 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

> Date: Sun, 11 Oct 2026 10:32:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

#syz test

--- x/drivers/nvme/target/fc.c
+++ y/drivers/nvme/target/fc.c
@@ -1620,6 +1620,7 @@ nvmet_fc_free_pending_reqs(struct nvmet_
 	}
 }
 
+static DEFINE_MUTEX(tgtp_mutex);
 /**
  * nvmet_fc_unregister_targetport - transport entry point called by an
  *                              LLDD to deregister/remove a previously
@@ -1637,6 +1638,7 @@ nvmet_fc_unregister_targetport(struct nv
 	struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);
 	unsigned long flags;
 
+	mutex_lock(&tgtp_mutex);
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 	list_del(&tgtport->tgt_list);
 	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
@@ -1645,6 +1647,7 @@ nvmet_fc_unregister_targetport(struct nv
 
 	/* terminate any outstanding associations */
 	__nvmet_fc_free_assocs(tgtport);
+	mutex_unlock(&tgtp_mutex);
 
 	flush_workqueue(nvmet_wq);
 
@@ -2919,6 +2922,7 @@ nvmet_fc_remove_port(struct nvmet_port *
 	struct nvmet_fc_tgtport *tgtport = NULL;
 	unsigned long flags;
 
+	mutex_lock(&tgtp_mutex);
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 	if (pe->tgtport && nvmet_fc_tgtport_get(pe->tgtport))
 		tgtport = pe->tgtport;
@@ -2933,6 +2937,7 @@ nvmet_fc_remove_port(struct nvmet_port *
 	}
 
 	kfree(pe);
+	mutex_unlock(&tgtp_mutex);
 }
 
 static void
--

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-12 12:41 ` Hillf Danton
@ 2026-10-12 13:11   ` syzbot
  0 siblings, 0 replies; 20+ messages in thread
From: syzbot @ 2026-10-12 13:11 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: corrupted list in nvmet_fc_remove_port

 non-slab/vmalloc memory
list_del corruption. prev->next should be ffff888042a5f220, but was 0000000000000000. (prev=ffffffff9aecd340)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:64!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6805 Comm: syz.2.84 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 8b f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 4c bf 58 fd 49 8b 17 48 c7 c7 40 6e cc 8b 48 89 de 4c 89 f9 e8 27 88 4c fc 90 <0f> 0b 4c 89 f7 e8 5c f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 1d
RSP: 0000:ffffc90005157c30 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff888042a5f220 RCX: 112f50d9f18e7400
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000201 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed101708490b R12: 1ffffffff35d9a68
R13: dffffc0000000000 R14: ffffffff85f7e820 R15: ffffffff9aecd340
FS:  00007f076720d6c0(0000) GS:ffff8881249bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564cae572950 CR3: 00000000361dc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:140 [inline]
 __list_del_entry include/linux/list.h:261 [inline]
 list_del include/linux/list.h:275 [inline]
 nvmet_fc_portentry_unbind drivers/nvme/target/fc.c:1281 [inline]
 nvmet_fc_remove_port+0x179/0x340 drivers/nvme/target/fc.c:2931
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5678
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5748
 __do_sys_unlinkat fs/namei.c:5777 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5769
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0767bce1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f076720d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007f0767e56090 RCX: 00007f0767bce1d9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: ffffffffffffff9c
RBP: 00007f0767c65888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0767e56128 R14: 00007f0767e56090 R15: 00007ffc73e653d8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 8b f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 4c bf 58 fd 49 8b 17 48 c7 c7 40 6e cc 8b 48 89 de 4c 89 f9 e8 27 88 4c fc 90 <0f> 0b 4c 89 f7 e8 5c f8 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 1d
RSP: 0000:ffffc90005157c30 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff888042a5f220 RCX: 112f50d9f18e7400
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000201 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed101708490b R12: 1ffffffff35d9a68
R13: dffffc0000000000 R14: ffffffff85f7e820 R15: ffffffff9aecd340
FS:  00007f076720d6c0(0000) GS:ffff8881249bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564cae572950 CR3: 00000000361dc000 CR4: 00000000003526f0


Tested on:

commit:         24a19b95 Linux 7.3-rc7
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=131aa9c9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=10728f15580000


^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-11 17:32 [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port syzbot
                   ` (3 preceding siblings ...)
  2026-10-12 12:41 ` Hillf Danton
@ 2026-10-17  2:09 ` Hillf Danton
  2026-10-17  2:50   ` syzbot
  2026-10-17  4:50   ` Nhật Anh Nguyễn Duy
  2026-10-17  4:41 ` Hillf Danton
                   ` (3 subsequent siblings)
  8 siblings, 2 replies; 20+ messages in thread
From: Hillf Danton @ 2026-10-17  2:09 UTC (permalink / raw)
  To: syzbot; +Cc: Nguyen Duy Nhat Anh, linux-kernel, syzkaller-bugs

> Date: Sun, 11 Oct 2026 10:32:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

Test Nguyen's idea.

#syz test

--- x/drivers/nvme/target/fc.c
+++ y/drivers/nvme/target/fc.c
@@ -1319,12 +1319,13 @@ nvmet_fc_portentry_rebind_tgt(struct nvm
 
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 	list_for_each_entry(pe, &nvmet_fc_portentry_list, pe_list) {
+		if (pe->tgtport)
+			continue;
 		if (tgtport->fc_target_port.node_name == pe->node_name &&
 		    tgtport->fc_target_port.port_name == pe->port_name) {
 			if (!nvmet_fc_tgtport_get(tgtport))
-				continue;
+				break;
 
-			WARN_ON(pe->tgtport);
 			tgtport->pe = pe;
 			pe->tgtport = tgtport;
 			break;
--

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-17  2:09 ` Hillf Danton
@ 2026-10-17  2:50   ` syzbot
  2026-10-17  4:50   ` Nhật Anh Nguyễn Duy
  1 sibling, 0 replies; 20+ messages in thread
From: syzbot @ 2026-10-17  2:50 UTC (permalink / raw)
  To: hdanton, linux-kernel, neganhat, syzkaller-bugs

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: corrupted list in nvmet_fc_remove_port

 non-slab/vmalloc memory
list_del corruption. prev->next should be ffff88802b1c4020, but was 0000000000000000. (prev=ffffffff9aecd380)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:64!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 6659 Comm: syz.1.38 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 fb f0 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 bc b7 58 fd 49 8b 17 48 c7 c7 40 6f cc 8b 48 89 de 4c 89 f9 e8 e7 82 4c fc 90 <0f> 0b 4c 89 f7 e8 cc f0 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 8d
RSP: 0018:ffffc90004f07c30 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff88802b1c4020 RCX: 1c46e68f21e3c500
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000201 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10170a490b R12: 1ffffffff35d9a70
R13: dffffc0000000000 R14: ffffffff85f7f100 R15: ffffffff9aecd380
FS:  00007fccc25bd6c0(0000) GS:ffff888124abb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbda5aaf000 CR3: 000000002c6f4000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:140 [inline]
 __list_del_entry include/linux/list.h:261 [inline]
 list_del include/linux/list.h:275 [inline]
 nvmet_fc_portentry_unbind drivers/nvme/target/fc.c:1281 [inline]
 nvmet_fc_remove_port+0x16b/0x320 drivers/nvme/target/fc.c:2928
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5648
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5718
 __do_sys_unlinkat fs/namei.c:5747 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fccc2f7e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fccc25bd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007fccc3206090 RCX: 00007fccc2f7e1d9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: ffffffffffffff9c
RBP: 00007fccc3015888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fccc3206128 R14: 00007fccc3206090 R15: 00007ffcdc929c08
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 fb f0 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 bc b7 58 fd 49 8b 17 48 c7 c7 40 6f cc 8b 48 89 de 4c 89 f9 e8 e7 82 4c fc 90 <0f> 0b 4c 89 f7 e8 cc f0 37 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 8d
RSP: 0018:ffffc90004f07c30 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff88802b1c4020 RCX: 1c46e68f21e3c500
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000201 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10170a490b R12: 1ffffffff35d9a70
R13: dffffc0000000000 R14: ffffffff85f7f100 R15: ffffffff9aecd380
FS:  00007fccc25bd6c0(0000) GS:ffff888124abb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbda5aaf000 CR3: 000000002c6f4000 CR4: 00000000003526f0


Tested on:

commit:         58161ead Merge tag 'drm-fixes-2026-10-17' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=179ce895580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b38d39c45202f4fa
dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
compiler:       Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13ea960d580000


^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-17  2:09 ` Hillf Danton
  2026-10-17  2:50   ` syzbot
@ 2026-10-17  4:50   ` Nhật Anh Nguyễn Duy
  1 sibling, 0 replies; 20+ messages in thread
From: Nhật Anh Nguyễn Duy @ 2026-10-17  4:50 UTC (permalink / raw)
  To: Hillf Danton; +Cc: syzbot, linux-kernel, syzkaller-bugs

On Sat, Oct 17, 2026 at 9:09 AM Hillf Danton <hdanton@sina.com> wrote:
>
> > Date: Sun, 11 Oct 2026 10:32:37 -0700 [thread overview]
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> > git tree:       upstream
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> > dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000
>
> Test Nguyen's idea.
>
> #syz test
>
> --- x/drivers/nvme/target/fc.c
> +++ y/drivers/nvme/target/fc.c
> @@ -1319,12 +1319,13 @@ nvmet_fc_portentry_rebind_tgt(struct nvm
>
>         spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
>         list_for_each_entry(pe, &nvmet_fc_portentry_list, pe_list) {
> +               if (pe->tgtport)
> +                       continue;
>                 if (tgtport->fc_target_port.node_name == pe->node_name &&
>                     tgtport->fc_target_port.port_name == pe->port_name) {
>                         if (!nvmet_fc_tgtport_get(tgtport))
> -                               continue;
> +                               break;
>
> -                       WARN_ON(pe->tgtport);
>                         tgtport->pe = pe;
>                         pe->tgtport = tgtport;
>                         break;
> --

[Resending to list + CCs — accidentally dropped them in my previous
reply, apologies]

You may need to recheck the commit you're testing
on because #syz test or #syz test: upstream master runs on the latest
commit of the repository. Something like #syz test: upstream [commit]
would let the bot test it on the specific commit the bug was
discovered in.

Best regards,
Nhat Anh

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-11 17:32 [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port syzbot
                   ` (4 preceding siblings ...)
  2026-10-17  2:09 ` Hillf Danton
@ 2026-10-17  4:41 ` Hillf Danton
  2026-10-17  5:12   ` syzbot
  2026-10-17  5:42 ` Hillf Danton
                   ` (2 subsequent siblings)
  8 siblings, 1 reply; 20+ messages in thread
From: Hillf Danton @ 2026-10-17  4:41 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

> Date: Sun, 11 Oct 2026 10:32:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

#syz test

--- x/drivers/nvme/target/fc.c
+++ y/drivers/nvme/target/fc.c
@@ -1271,9 +1271,17 @@ nvmet_fc_portentry_bind(struct nvmet_fc_
 static void
 nvmet_fc_portentry_unbind(struct nvmet_fc_port_entry *pe)
 {
+	struct nvmet_fc_port_entry *entry;
 	unsigned long flags;
 
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	list_for_each_entry(entry, &nvmet_fc_portentry_list, pe_list) {
+		if (entry == pe)
+			goto out;
+	}
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+	return;
+out:
 	if (pe->tgtport) {
 		nvmet_fc_tgtport_put(pe->tgtport);
 		pe->tgtport->pe = NULL;
--

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-17  4:41 ` Hillf Danton
@ 2026-10-17  5:12   ` syzbot
  0 siblings, 0 replies; 20+ messages in thread
From: syzbot @ 2026-10-17  5:12 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: user-memory-access Read in nvmet_fc_tgt_a_get

==================================================================
BUG: KASAN: user-memory-access in instrument_atomic_read include/linux/instrumented.h:82 [inline]
BUG: KASAN: user-memory-access in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: user-memory-access in refcount_read include/linux/refcount.h:170 [inline]
BUG: KASAN: user-memory-access in __refcount_add_not_zero include/linux/refcount.h:176 [inline]
BUG: KASAN: user-memory-access in __refcount_inc_not_zero include/linux/refcount.h:317 [inline]
BUG: KASAN: user-memory-access in refcount_inc_not_zero include/linux/refcount.h:335 [inline]
BUG: KASAN: user-memory-access in kref_get_unless_zero include/linux/kref.h:133 [inline]
BUG: KASAN: user-memory-access in nvmet_fc_tgt_a_get+0x82/0x1d0 drivers/nvme/target/fc.c:1201
Read of size 4 at addr 000000000008c617 by task syz.2.87/6911

CPU: 1 UID: 0 PID: 6911 Comm: syz.2.87 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read include/linux/instrumented.h:82 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 refcount_read include/linux/refcount.h:170 [inline]
 __refcount_add_not_zero include/linux/refcount.h:176 [inline]
 __refcount_inc_not_zero include/linux/refcount.h:317 [inline]
 refcount_inc_not_zero include/linux/refcount.h:335 [inline]
 kref_get_unless_zero include/linux/kref.h:133 [inline]
 nvmet_fc_tgt_a_get+0x82/0x1d0 drivers/nvme/target/fc.c:1201
 __nvmet_fc_free_assocs+0x10c/0x380 drivers/nvme/target/fc.c:1488
 nvmet_fc_remove_port+0x2a5/0x350 drivers/nvme/target/fc.c:2939
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5648
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5718
 __do_sys_unlinkat fs/namei.c:5747 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1994b5e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f199419d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007f1994de6090 RCX: 00007f1994b5e1d9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: ffffffffffffff9c
RBP: 00007f1994bf5888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1994de6128 R14: 00007f1994de6090 R15: 00007ffcd30e9a38
 </TASK>
==================================================================


Tested on:

commit:         58161ead Merge tag 'drm-fixes-2026-10-17' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1492efd1580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b38d39c45202f4fa
dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
compiler:       Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15d8320d580000


^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-11 17:32 [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port syzbot
                   ` (5 preceding siblings ...)
  2026-10-17  4:41 ` Hillf Danton
@ 2026-10-17  5:42 ` Hillf Danton
  2026-10-17  6:53   ` syzbot
  2026-10-17  7:30 ` Hillf Danton
  2026-10-17  9:20 ` Hillf Danton
  8 siblings, 1 reply; 20+ messages in thread
From: Hillf Danton @ 2026-10-17  5:42 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

> Date: Sun, 11 Oct 2026 10:32:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

#syz test

--- x/drivers/nvme/target/fc.c
+++ y/drivers/nvme/target/fc.c
@@ -1271,9 +1271,17 @@ nvmet_fc_portentry_bind(struct nvmet_fc_
 static void
 nvmet_fc_portentry_unbind(struct nvmet_fc_port_entry *pe)
 {
+	struct nvmet_fc_port_entry *entry;
 	unsigned long flags;
 
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	list_for_each_entry(entry, &nvmet_fc_portentry_list, pe_list) {
+		if (entry == pe)
+			goto out;
+	}
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+	return;
+out:
 	if (pe->tgtport) {
 		nvmet_fc_tgtport_put(pe->tgtport);
 		pe->tgtport->pe = NULL;
@@ -1643,8 +1651,10 @@ nvmet_fc_unregister_targetport(struct nv
 
 	nvmet_fc_portentry_unbind_tgt(tgtport);
 
+	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 	/* terminate any outstanding associations */
 	__nvmet_fc_free_assocs(tgtport);
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 
 	flush_workqueue(nvmet_wq);
 
@@ -2927,8 +2937,10 @@ nvmet_fc_remove_port(struct nvmet_port *
 	nvmet_fc_portentry_unbind(pe);
 
 	if (tgtport) {
+		spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 		/* terminate any outstanding associations */
 		__nvmet_fc_free_assocs(tgtport);
+		spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 		nvmet_fc_tgtport_put(tgtport);
 	}
 
--

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-17  5:42 ` Hillf Danton
@ 2026-10-17  6:53   ` syzbot
  0 siblings, 0 replies; 20+ messages in thread
From: syzbot @ 2026-10-17  6:53 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: user-memory-access Read in nvmet_fc_tgt_a_get

==================================================================
BUG: KASAN: user-memory-access in instrument_atomic_read include/linux/instrumented.h:82 [inline]
BUG: KASAN: user-memory-access in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: user-memory-access in refcount_read include/linux/refcount.h:170 [inline]
BUG: KASAN: user-memory-access in __refcount_add_not_zero include/linux/refcount.h:176 [inline]
BUG: KASAN: user-memory-access in __refcount_inc_not_zero include/linux/refcount.h:317 [inline]
BUG: KASAN: user-memory-access in refcount_inc_not_zero include/linux/refcount.h:335 [inline]
BUG: KASAN: user-memory-access in kref_get_unless_zero include/linux/kref.h:133 [inline]
BUG: KASAN: user-memory-access in nvmet_fc_tgt_a_get+0x82/0x1d0 drivers/nvme/target/fc.c:1201
Read of size 4 at addr 000000000008c617 by task syz.2.58/6775

CPU: 1 UID: 0 PID: 6775 Comm: syz.2.58 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read include/linux/instrumented.h:82 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 refcount_read include/linux/refcount.h:170 [inline]
 __refcount_add_not_zero include/linux/refcount.h:176 [inline]
 __refcount_inc_not_zero include/linux/refcount.h:317 [inline]
 refcount_inc_not_zero include/linux/refcount.h:335 [inline]
 kref_get_unless_zero include/linux/kref.h:133 [inline]
 nvmet_fc_tgt_a_get+0x82/0x1d0 drivers/nvme/target/fc.c:1201
 __nvmet_fc_free_assocs+0x10c/0x380 drivers/nvme/target/fc.c:1488
 nvmet_fc_remove_port+0x2b1/0x360 drivers/nvme/target/fc.c:2942
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5648
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5718
 __do_sys_unlinkat fs/namei.c:5747 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fedc366e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fedc2cad028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007fedc38f6090 RCX: 00007fedc366e1d9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: ffffffffffffff9c
RBP: 00007fedc3705888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fedc38f6128 R14: 00007fedc38f6090 R15: 00007ffd3089d1a8
 </TASK>
==================================================================


Tested on:

commit:         58161ead Merge tag 'drm-fixes-2026-10-17' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14e66ce1580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b38d39c45202f4fa
dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
compiler:       Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=175d34e1580000


^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-11 17:32 [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port syzbot
                   ` (6 preceding siblings ...)
  2026-10-17  5:42 ` Hillf Danton
@ 2026-10-17  7:30 ` Hillf Danton
  2026-10-17  7:55   ` syzbot
  2026-10-17  9:20 ` Hillf Danton
  8 siblings, 1 reply; 20+ messages in thread
From: Hillf Danton @ 2026-10-17  7:30 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

> Date: Sun, 11 Oct 2026 10:32:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

#syz test

--- x/drivers/nvme/target/fc.c
+++ y/drivers/nvme/target/fc.c
@@ -113,6 +113,7 @@ struct nvmet_fc_tgtport {
 	struct nvmet_fc_port_entry	*pe;
 	struct kref			ref;
 	u32				max_sg_cnt;
+	int				assoc_freed;
 };
 
 struct nvmet_fc_port_entry {
@@ -1271,9 +1272,17 @@ nvmet_fc_portentry_bind(struct nvmet_fc_
 static void
 nvmet_fc_portentry_unbind(struct nvmet_fc_port_entry *pe)
 {
+	struct nvmet_fc_port_entry *entry;
 	unsigned long flags;
 
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	list_for_each_entry(entry, &nvmet_fc_portentry_list, pe_list) {
+		if (entry == pe)
+			goto out;
+	}
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+	return;
+out:
 	if (pe->tgtport) {
 		nvmet_fc_tgtport_put(pe->tgtport);
 		pe->tgtport->pe = NULL;
@@ -1475,6 +1484,9 @@ __nvmet_fc_free_assocs(struct nvmet_fc_t
 {
 	struct nvmet_fc_tgt_assoc *assoc;
 
+	if (tgtport->assoc_freed)
+		return;
+	tgtport->assoc_freed = 1;
 	rcu_read_lock();
 	list_for_each_entry_rcu(assoc, &tgtport->assoc_list, a_list) {
 		if (!nvmet_fc_tgt_a_get(assoc))
@@ -1643,8 +1655,10 @@ nvmet_fc_unregister_targetport(struct nv
 
 	nvmet_fc_portentry_unbind_tgt(tgtport);
 
+	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 	/* terminate any outstanding associations */
 	__nvmet_fc_free_assocs(tgtport);
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 
 	flush_workqueue(nvmet_wq);
 
@@ -2927,8 +2941,10 @@ nvmet_fc_remove_port(struct nvmet_port *
 	nvmet_fc_portentry_unbind(pe);
 
 	if (tgtport) {
+		spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 		/* terminate any outstanding associations */
 		__nvmet_fc_free_assocs(tgtport);
+		spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 		nvmet_fc_tgtport_put(tgtport);
 	}
 
--

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-17  7:30 ` Hillf Danton
@ 2026-10-17  7:55   ` syzbot
  0 siblings, 0 replies; 20+ messages in thread
From: syzbot @ 2026-10-17  7:55 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: user-memory-access Read in nvmet_fc_tgt_a_get

==================================================================
BUG: KASAN: user-memory-access in instrument_atomic_read include/linux/instrumented.h:82 [inline]
BUG: KASAN: user-memory-access in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: user-memory-access in refcount_read include/linux/refcount.h:170 [inline]
BUG: KASAN: user-memory-access in __refcount_add_not_zero include/linux/refcount.h:176 [inline]
BUG: KASAN: user-memory-access in __refcount_inc_not_zero include/linux/refcount.h:317 [inline]
BUG: KASAN: user-memory-access in refcount_inc_not_zero include/linux/refcount.h:335 [inline]
BUG: KASAN: user-memory-access in kref_get_unless_zero include/linux/kref.h:133 [inline]
BUG: KASAN: user-memory-access in nvmet_fc_tgt_a_get+0x82/0x1d0 drivers/nvme/target/fc.c:1202
Read of size 4 at addr 000000000008c617 by task syz.3.43/6693

CPU: 1 UID: 0 PID: 6693 Comm: syz.3.43 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Goo
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read include/linux/instrumented.h:82 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 refcount_read include/linux/refcount.h:170 [inline]
 __refcount_add_not_zero include/linux/refcount.h:176 [inline]
 __refcount_inc_not_zero include/linux/refcount.h:317 [inline]
 refcount_inc_not_zero include/linux/refcount.h:335 [inline]
 kref_get_unless_zero include/linux/kref.h:133 [inline]
 nvmet_fc_tgt_a_get+0x82/0x1d0 drivers/nvme/target/fc.c:1202
 __nvmet_fc_free_assocs+0x15a/0x410 drivers/nvme/target/fc.c:1492
 nvmet_fc_remove_port+0x2b1/0x360 drivers/nvme/target/fc.c:2946
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5648
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5718
 __do_sys_unlinkat fs/namei.c:5747 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbccffce1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbccf60d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007fbcd0256090 RCX: 00007fbccffce1d9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: ffffffffffffff9c
RBP: 00007fbcd0065888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbcd0256128 R14: 00007fbcd0256090 R15: 00007fffd68320f8
 </TASK>
==================================================================


Tested on:

commit:         58161ead Merge tag 'drm-fixes-2026-10-17' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16ac320d580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b38d39c45202f4fa
dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
compiler:       Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15740f01580000


^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-11 17:32 [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port syzbot
                   ` (7 preceding siblings ...)
  2026-10-17  7:30 ` Hillf Danton
@ 2026-10-17  9:20 ` Hillf Danton
  2026-10-17 10:30   ` syzbot
  8 siblings, 1 reply; 20+ messages in thread
From: Hillf Danton @ 2026-10-17  9:20 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

> Date: Sun, 11 Oct 2026 10:32:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

#syz test

--- x/drivers/nvme/target/fc.c
+++ y/drivers/nvme/target/fc.c
@@ -113,6 +113,7 @@ struct nvmet_fc_tgtport {
 	struct nvmet_fc_port_entry	*pe;
 	struct kref			ref;
 	u32				max_sg_cnt;
+	int				assoc_freed;
 };
 
 struct nvmet_fc_port_entry {
@@ -1271,9 +1272,17 @@ nvmet_fc_portentry_bind(struct nvmet_fc_
 static void
 nvmet_fc_portentry_unbind(struct nvmet_fc_port_entry *pe)
 {
+	struct nvmet_fc_port_entry *entry;
 	unsigned long flags;
 
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	list_for_each_entry(entry, &nvmet_fc_portentry_list, pe_list) {
+		if (entry == pe)
+			goto out;
+	}
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+	return;
+out:
 	if (pe->tgtport) {
 		nvmet_fc_tgtport_put(pe->tgtport);
 		pe->tgtport->pe = NULL;
@@ -1474,14 +1483,20 @@ static void
 __nvmet_fc_free_assocs(struct nvmet_fc_tgtport *tgtport)
 {
 	struct nvmet_fc_tgt_assoc *assoc;
+	unsigned long flags;
 
+	if (tgtport->assoc_freed)
+		return;
+	tgtport->assoc_freed = 1;
 	rcu_read_lock();
+	spin_lock_irqsave(&tgtport->lock, flags);
 	list_for_each_entry_rcu(assoc, &tgtport->assoc_list, a_list) {
 		if (!nvmet_fc_tgt_a_get(assoc))
 			continue;
 		nvmet_fc_schedule_delete_assoc(assoc);
 		nvmet_fc_tgt_a_put(assoc);
 	}
+	spin_unlock_irqrestore(&tgtport->lock, flags);
 	rcu_read_unlock();
 }
 
@@ -1643,8 +1658,10 @@ nvmet_fc_unregister_targetport(struct nv
 
 	nvmet_fc_portentry_unbind_tgt(tgtport);
 
+	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 	/* terminate any outstanding associations */
 	__nvmet_fc_free_assocs(tgtport);
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 
 	flush_workqueue(nvmet_wq);
 
@@ -2927,8 +2944,10 @@ nvmet_fc_remove_port(struct nvmet_port *
 	nvmet_fc_portentry_unbind(pe);
 
 	if (tgtport) {
+		spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 		/* terminate any outstanding associations */
 		__nvmet_fc_free_assocs(tgtport);
+		spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 		nvmet_fc_tgtport_put(tgtport);
 	}
 
--

^ permalink raw reply	[flat|nested] 20+ messages in thread

* Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port
  2026-10-17  9:20 ` Hillf Danton
@ 2026-10-17 10:30   ` syzbot
  0 siblings, 0 replies; 20+ messages in thread
From: syzbot @ 2026-10-17 10:30 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: trying to register non-static key in __nvmet_fc_free_assocs

INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 0 UID: 0 PID: 6854 Comm: syz.0.124 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 assign_lock_key+0x133/0x150 kernel/locking/lockdep.c:1028
 register_lock_class+0xcc/0x2e0 kernel/locking/lockdep.c:1343
 __lock_acquire+0x10c/0x2de0 kernel/locking/lockdep.c:5162
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56
 spin_lock include/linux/spinlock_rt.h:45 [inline]
 __nvmet_fc_free_assocs+0x12e/0x430 drivers/nvme/target/fc.c:1492
 nvmet_fc_remove_port+0x2b1/0x360 drivers/nvme/target/fc.c:2949
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5648
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5718
 __do_sys_unlinkat fs/namei.c:5747 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f94beb6e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f94be1ad028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007f94bedf6090 RCX: 00007f94beb6e1d9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: ffffffffffffff9c
RBP: 00007f94bec05888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f94bedf6128 R14: 00007f94bedf6090 R15: 00007ffc099f6dd8
 </TASK>
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in kernel/locking/qspinlock.h:68:9
index 16382 is out of range for type 'unsigned long[8]'
CPU: 0 UID: 0 PID: 6854 Comm: syz.0.124 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xe8/0xf0 lib/ubsan.c:455
 decode_tail kernel/locking/qspinlock.h:68 [inline]
 __pv_queued_spin_lock_slowpath+0xaf3/0xbc0 kernel/locking/qspinlock.c:307
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:37 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:71 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:115 [inline]
 do_raw_spin_lock+0x26c/0x2f0 kernel/locking/spinlock_debug.c:116
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:156 [inline]
 _raw_spin_lock_irqsave+0x4c/0x60 kernel/locking/spinlock.c:181
 rtlock_slowlock kernel/locking/rtmutex.c:1921 [inline]
 rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
 __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
 rt_spin_lock+0x157/0x400 kernel/locking/spinlock_rt.c:57
 spin_lock include/linux/spinlock_rt.h:45 [inline]
 __nvmet_fc_free_assocs+0x12e/0x430 drivers/nvme/target/fc.c:1492
 nvmet_fc_remove_port+0x2b1/0x360 drivers/nvme/target/fc.c:2949
 nvmet_disable_port+0x13e/0x1f0 drivers/nvme/target/core.c:400
 nvmet_port_subsys_drop_link+0x1e8/0x210 drivers/nvme/target/configfs.c:1123
 configfs_unlink+0x44f/0x6b0 fs/configfs/symlink.c:258
 vfs_unlink+0x27b/0x6e0 fs/namei.c:5648
 filename_unlinkat+0x3d3/0x610 fs/namei.c:5718
 __do_sys_unlinkat fs/namei.c:5747 [inline]
 __se_sys_unlinkat+0x83/0x1a0 fs/namei.c:5739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f94beb6e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f94be1ad028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007f94bedf6090 RCX: 00007f94beb6e1d9
RDX: 0000000000000000 RSI: 0000200000000780 RDI: ffffffffffffff9c
RBP: 00007f94bec05888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f94bedf6128 R14: 00007f94bedf6090 R15: 00007ffc099f6dd8
 </TASK>
---[ end trace ]---


Tested on:

commit:         58161ead Merge tag 'drm-fixes-2026-10-17' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10d88031580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b38d39c45202f4fa
dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
compiler:       Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=16d7f67f980000


^ permalink raw reply	[flat|nested] 20+ messages in thread

end of thread, other threads:[~2026-10-17 10:30 UTC | newest]

Thread overview: 20+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-10-11 17:32 [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port syzbot
2026-10-12  5:11 ` Hillf Danton
2026-10-12  5:50   ` syzbot
2026-10-12  7:58 ` Hillf Danton
2026-10-12  8:25   ` syzbot
2026-10-12 10:33 ` Hillf Danton
2026-10-12 11:01   ` syzbot
2026-10-12 12:41 ` Hillf Danton
2026-10-12 13:11   ` syzbot
2026-10-17  2:09 ` Hillf Danton
2026-10-17  2:50   ` syzbot
2026-10-17  4:50   ` Nhật Anh Nguyễn Duy
2026-10-17  4:41 ` Hillf Danton
2026-10-17  5:12   ` syzbot
2026-10-17  5:42 ` Hillf Danton
2026-10-17  6:53   ` syzbot
2026-10-17  7:30 ` Hillf Danton
2026-10-17  7:55   ` syzbot
2026-10-17  9:20 ` Hillf Danton
2026-10-17 10:30   ` syzbot

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