==================================================================
BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:791 [inline]
BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline]
BUG: KASAN: use-after-free in expire_timers kernel/time/timer.c:1482 [inline]
BUG: KASAN: use-after-free in __run_timers+0x7be/0xbe0 kernel/time/timer.c:1817
Write of size 8 at addr ffff8881e71ab1c8 by task udevd/163
CPU: 1 PID: 163 Comm: udevd Not tainted 5.4.290-syzkaller-00017-g6b07fcd94a6a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1d8/0x241 lib/dump_stack.c:118
print_address_description+0x8c/0x600 mm/kasan/report.c:384
__kasan_report+0xf3/0x120 mm/kasan/report.c:516
kasan_report+0x30/0x60 mm/kasan/common.c:653
__hlist_del include/linux/list.h:791 [inline]
detach_timer kernel/time/timer.c:824 [inline]
expire_timers kernel/time/timer.c:1482 [inline]
__run_timers+0x7be/0xbe0 kernel/time/timer.c:1817
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1830
__do_softirq+0x23b/0x6b7 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x195/0x1c0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:539 [inline]
smp_apic_timer_interrupt+0x11a/0x490 arch/x86/kernel/apic/apic.c:1161
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
RIP: 0010:unwind_next_frame+0x4d0/0x1ea0 arch/x86/kernel/unwind_orc.c:451
Code: 00 00 c6 03 01 49 c7 c5 e0 b3 a6 84 49 8d 55 04 49 8d 5d 05 49 89 d4 49 c1 ec 03 49 bf 00 00 00 00 00 fc ff df 43 0f b6 04 3c <84> c0 0f 85 55 15 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0
RSP: 0018:ffff8881ec20f0e0 EFLAGS: 00000a07 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffffff868856bd RCX: ffffffff86597814
RDX: ffffffff868856bc RSI: ffffffff868856b8 RDI: ffffffff812fbdbc
RBP: ffff8881ec20f3d0 R08: 0000000000000001 R09: ffff8881ec20f430
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff0d10ad7
R13: ffffffff868856b8 R14: 0000000000000000 R15: dffffc0000000000
arch_stack_walk+0x111/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x118/0x1c0 kernel/stacktrace.c:123
save_stack mm/kasan/common.c:70 [inline]
set_track mm/kasan/common.c:78 [inline]
__kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529
slab_post_alloc_hook mm/slab.h:584 [inline]
slab_alloc_node mm/slub.c:2829 [inline]
slab_alloc mm/slub.c:2837 [inline]
kmem_cache_alloc_trace+0xdc/0x260 mm/slub.c:2854
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:690 [inline]
kernfs_fop_open+0x31c/0xac0 fs/kernfs/file.c:647
do_dentry_open+0x964/0x1130 fs/open.c:806
do_last fs/namei.c:3565 [inline]
path_openat+0x29bf/0x34b0 fs/namei.c:3683
do_filp_open+0x20b/0x450 fs/namei.c:3713
do_sys_open+0x39c/0x810 fs/open.c:1123
do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f69ecef59a4
Code: 24 20 48 8d 44 24 30 48 89 44 24 28 64 8b 04 25 18 00 00 00 85 c0 75 2c 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 60 48 8b 15 55 a4 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007fffe6fd8610 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f69ecef59a4
RDX: 0000000000080000 RSI: 00007fffe6fd8748 RDI: 00000000ffffff9c
RBP: 00007fffe6fd8748 R08: 0000000000000008 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000
R13: 00005592b2391b42 R14: 0000000000000001 R15: 0000000000000000
Allocated by task 163:
save_stack mm/kasan/common.c:70 [inline]
set_track mm/kasan/common.c:78 [inline]
__kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529
slab_post_alloc_hook mm/slab.h:584 [inline]
slab_alloc_node mm/slub.c:2829 [inline]
slab_alloc mm/slub.c:2837 [inline]
kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842
getname_flags+0xb8/0x4e0 fs/namei.c:141
do_sys_open+0x357/0x810 fs/open.c:1117
do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1
Freed by task 163:
save_stack mm/kasan/common.c:70 [inline]
set_track mm/kasan/common.c:78 [inline]
kasan_set_free_info mm/kasan/common.c:345 [inline]
__kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487
slab_free_hook mm/slub.c:1455 [inline]
slab_free_freelist_hook mm/slub.c:1494 [inline]
slab_free mm/slub.c:3080 [inline]
kmem_cache_free+0x10b/0x2c0 mm/slub.c:3096
do_sys_open+0x65e/0x810 fs/open.c:1132
do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1
The buggy address belongs to the object at ffff8881e71aa200
which belongs to the cache names_cache of size 4096
The buggy address is located 4040 bytes inside of
4096-byte region [ffff8881e71aa200, ffff8881e71ab200)
The buggy address belongs to the page:
page:ffffea00079c6a00 refcount:1 mapcount:0 mapping:ffff8881f5cfd900 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5cfd900
raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL)
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook mm/page_alloc.c:2165 [inline]
prep_new_page+0x18f/0x370 mm/page_alloc.c:2171
get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794
__alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893
alloc_slab_page+0x39/0x3c0 mm/slub.c:343
allocate_slab mm/slub.c:1683 [inline]
new_slab+0x97/0x440 mm/slub.c:1749
new_slab_objects mm/slub.c:2505 [inline]
___slab_alloc+0x2fe/0x490 mm/slub.c:2667
__slab_alloc+0x62/0xa0 mm/slub.c:2707
slab_alloc_node mm/slub.c:2792 [inline]
slab_alloc mm/slub.c:2837 [inline]
kmem_cache_alloc+0x109/0x250 mm/slub.c:2842
getname_flags+0xb8/0x4e0 fs/namei.c:141
user_path_at_empty+0x28/0x50 fs/namei.c:2703
do_readlinkat+0x114/0x3a0 fs/stat.c:398
__do_sys_readlink fs/stat.c:431 [inline]
__se_sys_readlink fs/stat.c:428 [inline]
__x64_sys_readlink+0x7b/0x90 fs/stat.c:428
do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1176 [inline]
__free_pages_ok+0x847/0x950 mm/page_alloc.c:1438
free_the_page mm/page_alloc.c:4955 [inline]
__free_pages+0x91/0x140 mm/page_alloc.c:4961
device_release+0x6b/0x190 drivers/base/core.c:1776
kobject_cleanup lib/kobject.c:716 [inline]
kobject_release lib/kobject.c:747 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1e6/0x2f0 lib/kobject.c:764
netdev_run_todo+0xc44/0xdf0 net/core/dev.c:9488
tun_detach drivers/net/tun.c:766 [inline]
tun_chr_close+0xc1/0x130 drivers/net/tun.c:3563
__fput+0x262/0x680 fs/file_table.c:281
task_work_run+0x140/0x170 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0xcaf/0x2bc0 kernel/exit.c:861
do_group_exit+0x138/0x300 kernel/exit.c:984
get_signal+0xdb1/0x1440 kernel/signal.c:2738
do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809
exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159
prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194
swapgs_restore_regs_and_return_to_usermode+0x0/0x54
Memory state around the buggy address:
ffff8881e71ab080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881e71ab100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881e71ab180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881e71ab200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881e71ab280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 0 P4D 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 163 Comm: udevd Tainted: G B 5.4.290-syzkaller-00017-g6b07fcd94a6a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6f09d18 EFLAGS: 00010202
RAX: ffffffff8154e8ca RBX: 0000000000000101 RCX: ffff8881ec098000
RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881e71ab1c0
RBP: ffff8881f6f09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffff9cd0
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e71ab1c0
FS: 00007f69ecdcac80(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001ec046000 CR4: 00000000003406a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
call_timer_fn+0x36/0x390 kernel/time/timer.c:1448
expire_timers kernel/time/timer.c:1493 [inline]
__run_timers+0x879/0xbe0 kernel/time/timer.c:1817
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1830
__do_softirq+0x23b/0x6b7 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x195/0x1c0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:539 [inline]
smp_apic_timer_interrupt+0x11a/0x490 arch/x86/kernel/apic/apic.c:1161
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
RIP: 0010:unwind_next_frame+0x4d0/0x1ea0 arch/x86/kernel/unwind_orc.c:451
Code: 00 00 c6 03 01 49 c7 c5 e0 b3 a6 84 49 8d 55 04 49 8d 5d 05 49 89 d4 49 c1 ec 03 49 bf 00 00 00 00 00 fc ff df 43 0f b6 04 3c <84> c0 0f 85 55 15 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0
RSP: 0018:ffff8881ec20f0e0 EFLAGS: 00000a07 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffffff868856bd RCX: ffffffff86597814
RDX: ffffffff868856bc RSI: ffffffff868856b8 RDI: ffffffff812fbdbc
RBP: ffff8881ec20f3d0 R08: 0000000000000001 R09: ffff8881ec20f430
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff0d10ad7
R13: ffffffff868856b8 R14: 0000000000000000 R15: dffffc0000000000
arch_stack_walk+0x111/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x118/0x1c0 kernel/stacktrace.c:123
save_stack mm/kasan/common.c:70 [inline]
set_track mm/kasan/common.c:78 [inline]
__kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529
slab_post_alloc_hook mm/slab.h:584 [inline]
slab_alloc_node mm/slub.c:2829 [inline]
slab_alloc mm/slub.c:2837 [inline]
kmem_cache_alloc_trace+0xdc/0x260 mm/slub.c:2854
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:690 [inline]
kernfs_fop_open+0x31c/0xac0 fs/kernfs/file.c:647
do_dentry_open+0x964/0x1130 fs/open.c:806
do_last fs/namei.c:3565 [inline]
path_openat+0x29bf/0x34b0 fs/namei.c:3683
do_filp_open+0x20b/0x450 fs/namei.c:3713
do_sys_open+0x39c/0x810 fs/open.c:1123
do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f69ecef59a4
Code: 24 20 48 8d 44 24 30 48 89 44 24 28 64 8b 04 25 18 00 00 00 85 c0 75 2c 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 60 48 8b 15 55 a4 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007fffe6fd8610 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f69ecef59a4
RDX: 0000000000080000 RSI: 00007fffe6fd8748 RDI: 00000000ffffff9c
RBP: 00007fffe6fd8748 R08: 0000000000000008 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000
R13: 00005592b2391b42 R14: 0000000000000001 R15: 0000000000000000
Modules linked in:
CR2: 0000000000000000
---[ end trace e56c5859f4e54db6 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6f09d18 EFLAGS: 00010202
RAX: ffffffff8154e8ca RBX: 0000000000000101 RCX: ffff8881ec098000
RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881e71ab1c0
RBP: ffff8881f6f09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffff9cd0
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e71ab1c0
FS: 00007f69ecdcac80(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001ec046000 CR4: 00000000003406a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: c6 03 01 movb $0x1,(%rbx)
5: 49 c7 c5 e0 b3 a6 84 mov $0xffffffff84a6b3e0,%r13
c: 49 8d 55 04 lea 0x4(%r13),%rdx
10: 49 8d 5d 05 lea 0x5(%r13),%rbx
14: 49 89 d4 mov %rdx,%r12
17: 49 c1 ec 03 shr $0x3,%r12
1b: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15
22: fc ff df
25: 43 0f b6 04 3c movzbl (%r12,%r15,1),%eax
* 2a: 84 c0 test %al,%al <-- trapping instruction
2c: 0f 85 55 15 00 00 jne 0x1587
32: 48 89 d8 mov %rbx,%rax
35: 48 c1 e8 03 shr $0x3,%rax
39: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax
3e: 84 c0 test %al,%al