WARNING in __ioremap_caller

Status: upstream: reported C repro on 2026/02/22 11:33
Subsystems: kernel
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+49b1021becba70c1f3f6@syzkaller.appspotmail.com
First crash: 200d, last: 1d14h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
e5ec6b42 repro-c Reproduced: ✅ WARNING in __ioremap_caller 2026/08/06 20:23 2026/08/07 10:10 2026/08/07 13:32 c38879ea
d1ea2ef5 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ✅ WARNING in __ioremap_caller 2026/05/26 05:01 2026/05/26 05:01 2026/05/26 05:58 c69befb3
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] WARNING in __ioremap_caller 1 (3) 2026/09/04 23:20

Sample crash report:
------------[ 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

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/04 22:02 upstream bc35965f6940 44dda43b .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in __ioremap_caller
2026/07/15 16:51 upstream 58717b2a1365 a4ed0f4f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in __ioremap_caller
2026/07/02 12:56 upstream 4a50a141f05a 27192279 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in __ioremap_caller
2026/04/14 18:23 upstream d60bc1401583 362d1323 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in __ioremap_caller
2026/02/18 11:27 upstream 2961f841b025 39751c21 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in __ioremap_caller
2026/08/21 07:42 upstream 9d2ed026f031 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in __ioremap_caller
* Struck through repros no longer work on HEAD.