From: syzbot <syzbot+49b1021becba70c1f3f6@syzkaller.appspotmail.com>
To: bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com,
linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com,
peterz@infradead.org, syzkaller-bugs@googlegroups.com,
tglx@kernel.org, x86@kernel.org
Subject: Re: [syzbot] [kernel?] WARNING in __ioremap_caller
Date: Fri, 04 Sep 2026 15:02:32 -0700 [thread overview]
Message-ID: <6a9b3ff8.04649fcc.10325f.0005.GAE@google.com> (raw)
In-Reply-To: <699ae98c.050a0220.340abe.0d31.GAE@google.com>
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
---
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.
next prev parent reply other threads:[~2026-09-04 22:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-22 11:33 syzbot
2026-09-04 22:02 ` syzbot [this message]
2026-09-04 23:20 ` Dave Hansen
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