[syzbot] [kernel?] WARNING in __ioremap_caller

[syzbot] [kernel?] WARNING in __ioremap_caller

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    2961f841b025 Merge tag 'turbostat-2026.02.14' of git://git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17674594580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6259cfbe2d15cac4
dashboard link: https://syzkaller.appspot.com/bug?extid=49b1021becba70c1f3f6
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4db266f4e980/disk-2961f841.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9ec134f45048/vmlinux-2961f841.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5ba4f405d712/bzImage-2961f841.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+49b1021becba70c1f3f6@syzkaller.appspotmail.com

ioremap: invalid physical address a729678abbd17117
------------[ cut here ]------------
1
WARNING: arch/x86/mm/ioremap.c:206 at __ioremap_caller.isra.0.cold+0x59/0xa4 arch/x86/mm/ioremap.c:206, CPU#0: syz.1.4191/26162
Modules linked in:
CPU: 0 UID: 0 PID: 26162 Comm: syz.1.4191 Tainted: G     U       L      syzkaller #0 PREEMPT(full) 
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__ioremap_caller.isra.0.cold+0x59/0xa4 arch/x86/mm/ioremap.c:206
Code: 48 8b 34 24 48 c7 c7 e0 fc ab 8b e8 30 1d 01 00 e9 61 c2 97 00 e8 76 ca e6 00 4c 89 ee 48 c7 c7 40 fb ab 8b e8 17 1d 01 00 90 <0f> 0b 90 e9 41 c2 97 00 e8 59 ca e6 00 41 0f b6 d7 4c 89 ee 48 c7
RSP: 0018:ffffc90004d1f718 EFLAGS: 00010286
RAX: 0000000000000032 RBX: 1ffff920009a3ee7 RCX: 0000000000000000
RDX: 0000000000000032 RSI: ffffffff81e6f929 RDI: fffff520009a3ed4
RBP: 0000000000000040 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000038c68 R12: a729678abbd17156
R13: a729678abbd17117 R14: 0000000000000000 R15: 0000000000029ca5
FS:  00007fc5be1016c0(0000) GS:ffff888124351000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32306ff8 CR3: 00000000831e0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 ioremap_cache arch/x86/mm/ioremap.c:436 [inline]
 arch_memremap_wb+0x23/0x40 arch/x86/mm/ioremap.c:508
 memremap+0x1cb/0x7d0 kernel/iomem.c:95
 pcibios_device_add+0x101/0x600 arch/x86/pci/common.c:652
 pci_device_add+0xd4f/0x1810 drivers/pci/probe.c:2761
 pci_scan_single_device drivers/pci/probe.c:2793 [inline]
 pci_scan_single_device+0x1d0/0x240 drivers/pci/probe.c:2779
 pci_scan_slot+0x1c9/0x7c0 drivers/pci/probe.c:2876
 pci_scan_child_bus_extend+0x6b/0x7b0 drivers/pci/probe.c:3095
 pci_scan_child_bus drivers/pci/probe.c:3208 [inline]
 pci_rescan_bus+0x18/0x40 drivers/pci/probe.c:3499
 rescan_store+0xfb/0x130 drivers/pci/pci-sysfs.c:472
 bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352
 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+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc5bd19c629
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:00007fc5be101028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc5bd415fa0 RCX: 00007fc5bd19c629
RDX: 0000000000000001 RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007fc5bd232b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc5bd416038 R14: 00007fc5bd415fa0 R15: 00007ffc328057a8
 </TASK>


---
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Re: [syzbot] [kernel?] WARNING in __ioremap_caller

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    bc35965f6940 Merge tag 'mm-hotfixes-stable-2026-09-03-17-4..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=164e88f9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=85bc5cc2fc7394d9
dashboard link: https://syzkaller.appspot.com/bug?extid=49b1021becba70c1f3f6
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: i386
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16bca8f9580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16a09215580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-bc35965f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9eaaad19cc52/vmlinux-bc35965f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b6466cfeb6f0/bzImage-bc35965f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+49b1021becba70c1f3f6@syzkaller.appspotmail.com

------------[ cut here ]------------
ioremap on RAM at 0x000000001bf67000 - 0x000000001bf67fff
WARNING: arch/x86/mm/ioremap.c:216 at __ioremap_caller.isra.0+0x4c2/0x5f0 arch/x86/mm/ioremap.c:216, CPU#2: syz.0.17/5915
Modules linked in:
CPU: 2 UID: 0 PID: 5915 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
RIP: 0010:__ioremap_caller.isra.0+0x4d3/0x5f0 arch/x86/mm/ioremap.c:216
Code: 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc e8 45 cb 50 00 48 8d 3d 2e 85 8d 0f 48 8d 84 24 c0 00 00 00 48 8d 54 24 60 48 8d 70 c0 <67> 48 0f b9 3a eb 89 41 83 ff 04 75 32 e8 1b cb 50 00 bf 04 00 00
RSP: 0018:ffffc900036478a0 EFLAGS: 00010293
RAX: ffffc90003647960 RBX: 1ffff920006c8f18 RCX: 0000000000000000
RDX: ffffc90003647900 RSI: ffffc90003647920 RDI: ffffffff9147f620
RBP: 0000000000001000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000001
R13: 000000001bf67000 R14: 0000000000000002 R15: 000000001bf67000
FS:  0000000000000000(0000) GS:ffff888096b64000(0063) knlGS:0000000056c88480
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000000000018 CR3: 000000005eb62000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 generic_access_phys+0x130/0x4d0 mm/memory.c:7178
 kernfs_vma_access+0x1ce/0x280 fs/kernfs/file.c:437
 __access_remote_vm+0x58f/0x890 mm/memory.c:7256
 mem_rw+0x2a1/0x670 fs/proc/base.c:912
 do_loop_readv_writev fs/read_write.c:848 [inline]
 do_loop_readv_writev fs/read_write.c:836 [inline]
 vfs_readv+0x5d8/0x8d0 fs/read_write.c:1021
 do_readv+0x13e/0x340 fs/read_write.c:1081
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7f14fec
Code: Unable to access opcode bytes at 0xf7f14fc2.
RSP: 002b:00000000ffc02c5c EFLAGS: 00000296 ORIG_RAX: 0000000000000091
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000080000100
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess):
   0:	41 5c                	pop    %r12
   2:	41 5d                	pop    %r13
   4:	41 5e                	pop    %r14
   6:	41 5f                	pop    %r15
   8:	c3                   	ret
   9:	cc                   	int3
   a:	cc                   	int3
   b:	cc                   	int3
   c:	cc                   	int3
   d:	e8 45 cb 50 00       	call   0x50cb57
  12:	48 8d 3d 2e 85 8d 0f 	lea    0xf8d852e(%rip),%rdi        # 0xf8d8547
  19:	48 8d 84 24 c0 00 00 	lea    0xc0(%rsp),%rax
  20:	00
  21:	48 8d 54 24 60       	lea    0x60(%rsp),%rdx
  26:	48 8d 70 c0          	lea    -0x40(%rax),%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 89                	jmp    0xffffffba
  31:	41 83 ff 04          	cmp    $0x4,%r15d
  35:	75 32                	jne    0x69
  37:	e8 1b cb 50 00       	call   0x50cb57
  3c:	bf                   	.byte 0xbf
  3d:	04 00                	add    $0x0,%al


---
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#syz test: git://repo/address.git branch-or-commit-hash
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Re: [syzbot] [kernel?] WARNING in __ioremap_caller

[Dave Hansen]

On 9/4/26 15:02, syzbot wrote:
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16a09215580000

Heh, that's a fun reproducer as usual. Looks like it's mmap()'ing some
PCI device resource the accessing the mmap() with /proc/$pid/mem. The
thing that's weird is how a PCI device resource ends up pointing at
system RAM.

/proc/iomem might be enlightening as would 'lspci -vvv'. But it makes me
wonder if the PCI device enumeration inside the VM is broken or something.