[syzbot] [kernel?] KASAN: stack-out-of-bounds Write in __hrtimer_run_queues
From: syzbot
Date: Sun Nov 15 2026 - 03:26:40 EST
Hello,
syzbot found the following issue on:
HEAD commit: 23c62304dde2 Merge tag 'for-linus-7.4a-rc3-tag' of git://g..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=15adb9ad580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c210800cfc8f61e
dashboard link: https://syzkaller.appspot.com/bug?extid=c6b6d5e5800184a5fa86
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: i386
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b86d3d580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c6b6d5e5800184a5fa86@xxxxxxxxxxxxxxxxxxxxxxxxx
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 2 UID: 0 PID: 6558 Comm: syz.1.18 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:lookup_object lib/debugobjects.c:440 [inline]
RIP: 0010:debug_object_deactivate+0x19b/0x3b0 lib/debugobjects.c:938
Code: 48 c1 e8 03 42 80 3c 28 00 0f 85 8e 01 00 00 48 8b 1b 48 85 db 0f 84 32 01 00 00 48 8d 7b 18 41 83 c4 01 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 4c 01 00 00 4c 3b 73 18 75 c2 48 b8 00 00 00
RSP: 0018:ffffc90000548da0 EFLAGS: 00010003
RAX: 0000000000000002 RBX: ffffffffffffffff RCX: 0000000000000002
RDX: ffffffff9cee70b0 RSI: 0000000000000004 RDI: 0000000000000017
RBP: ffffc90000548e80 R08: 0000000000000001 R09: fffff520000a91a2
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000002
R13: dffffc0000000000 R14: ffffc9000635fd50 R15: 1ffff920000a91b6
FS: 0000000000000000(0000) GS:ffff888095472000(0063) knlGS:00000000f687eb40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000032963fff CR3: 000000006e2ab000 CR4: 0000000000352ef0
Call Trace:
<IRQ>
debug_hrtimer_deactivate kernel/time/hrtimer.c:491 [inline]
__run_hrtimer kernel/time/hrtimer.c:2047 [inline]
__hrtimer_run_queues+0x2e9/0x9a0 kernel/time/hrtimer.c:2136
hrtimer_interrupt+0x441/0xaa0 kernel/time/hrtimer.c:2255
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:220 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:229
Code: 90 f3 0f 1e fa 53 48 8b 74 24 08 48 89 fb 48 83 c7 18 e8 fa 5a f7 f5 48 89 df e8 82 b1 f7 f5 e8 0d a9 24 f6 fb bf 01 00 00 00 <e8> d2 77 e6 f5 65 48 83 3d c1 52 c9 09 00 74 06 5b c3 cc cc cc cc
RSP: 0018:ffffc90002f3fc08 EFLAGS: 00000202
RAX: 00000000000001c1 RBX: ffffffff90cc6660 RCX: 0000000000000080
RDX: 0000000000000001 RSI: ffffffff8e627409 RDI: 0000000000000001
RBP: 0000000000000060 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880226f3000
R13: 0000000063702f73 R14: ffffffff8be2e420 R15: 000000000000009c
pci_user_write_config_dword+0x150/0x230 drivers/pci/access.c:278
proc_bus_pci_write+0x531/0x5e0 drivers/pci/proc.c:173
pde_write fs/proc/inode.c:330 [inline]
proc_reg_write+0x240/0x330 fs/proc/inode.c:342
vfs_write+0x2aa/0x1040 fs/read_write.c:665
ksys_write+0x12a/0x250 fs/read_write.c:719
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
__do_fast_syscall_32+0x14d/0x8e0 arch/x86/entry/syscall_32.c:286
do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:311
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7fc4fbc
Code: d2 74 05 c1 e8 0c 89 02 8b 5d fc 31 c0 c9 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 2e 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 58 b8
RSP: 002b:00000000f687e50c EFLAGS: 00000292 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000080000300
RDX: 000000000000010f RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 000
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: 48 c1 e8 03 shr $0x3,%rax
4: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
9: 0f 85 8e 01 00 00 jne 0x19d
f: 48 8b 1b mov (%rbx),%rbx
12: 48 85 db test %rbx,%rbx
15: 0f 84 32 01 00 00 je 0x14d
1b: 48 8d 7b 18 lea 0x18(%rbx),%rdi
1f: 41 83 c4 01 add $0x1,%r12d
23: 48 89 f8 mov %rdi,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction
2f: 0f 85 4c 01 00 00 jne 0x181
35: 4c 3b 73 18 cmp 0x18(%rbx),%r14
39: 75 c2 jne 0xfffffffd
3b: 48 rex.W
3c: b8 .byte 0xb8
3d: 00 00 add %al,(%rax)
---
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