==================================================================
BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:814 [inline]
BUG: KASAN: use-after-free in enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541
Write of size 8 at addr ffff8881e53431c8 by task syz.8.3424/10189
CPU: 0 PID: 10189 Comm: syz.8.3424 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
__dump_stack+0x1e/0x20 lib/dump_stack.c:77
dump_stack+0x15b/0x1b8 lib/dump_stack.c:118
print_address_description+0x8d/0x4c0 mm/kasan/report.c:384
__kasan_report+0xef/0x120 mm/kasan/report.c:516
kasan_report+0x30/0x60 mm/kasan/common.c:653
__asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:137
hlist_add_head include/linux/list.h:814 [inline]
enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541
__internal_add_timer kernel/time/timer.c:554 [inline]
internal_add_timer+0x208/0x3e0 kernel/time/timer.c:604
__mod_timer+0x5ab/0x1150 kernel/time/timer.c:1065
mod_timer+0x1f/0x30 kernel/time/timer.c:1117
can_stat_update+0xbab/0xc40 net/can/proc.c:186
call_timer_fn+0x3c/0x380 kernel/time/timer.c:1448
expire_timers kernel/time/timer.c:1493 [inline]
__run_timers+0x81d/0xb60 kernel/time/timer.c:1817
run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830
__do_softirq+0x236/0x660 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x197/0x1c0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:539 [inline]
smp_apic_timer_interrupt+0x11d/0x490 arch/x86/kernel/apic/apic.c:1161
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
RIP: 0010:__sanitizer_cov_trace_pc+0x3a/0x50 kernel/kcov.c:193
Code: 65 8b 15 95 0e a3 7e f7 c2 00 01 1f 00 74 02 5d c3 8b 91 00 0a 00 00 83 fa 02 75 f3 48 8b 91 08 0a 00 00 48 8b 32 48 8d 7e 01 <8b> 89 04 0a 00 00 48 39 cf 73 da 48 89 44 f2 08 48 89 3a 5d c3 90
RSP: 0018:ffff8881d71ff5f8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffff818dc260 RBX: ffff8881f5c02780 RCX: ffff8881e8dc5e80
RDX: ffffc90005555000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffff8881d71ff5f8 R08: dffffc0000000000 R09: 0000000000000003
R10: ffffed103ae3fec4 R11: 1ffff1103ae3fec4 R12: ffff8881f5c02780
R13: ffffffff81b2fee1 R14: 0000000000000dc0 R15: dffffc0000000000
__should_failslab+0x20/0x150 mm/failslab.c:18
should_failslab+0x9/0x20 mm/slab_common.c:1836
slab_pre_alloc_hook mm/slab.h:567 [inline]
slab_alloc_node mm/slub.c:2742 [inline]
slab_alloc mm/slub.c:2837 [inline]
__kmalloc+0x53/0x2f0 mm/slub.c:3909
kmalloc include/linux/slab.h:561 [inline]
kzalloc include/linux/slab.h:690 [inline]
new_dir fs/proc/proc_sysctl.c:973 [inline]
get_subdir fs/proc/proc_sysctl.c:1018 [inline]
__register_sysctl_table+0x921/0x1130 fs/proc/proc_sysctl.c:1361
register_net_sysctl+0x2c/0x40 net/sysctl_net.c:121
neigh_sysctl_register+0x998/0xa70 net/core/neighbour.c:3718
devinet_sysctl_register+0xaf/0x1e0 net/ipv4/devinet.c:2639
inetdev_init+0x28a/0x430 net/ipv4/devinet.c:277
inetdev_event+0x1f8/0x1030 net/ipv4/devinet.c:1545
notifier_call_chain kernel/notifier.c:98 [inline]
__raw_notifier_call_chain kernel/notifier.c:399 [inline]
raw_notifier_call_chain+0xa0/0x120 kernel/notifier.c:406
call_netdevice_notifiers_info net/core/dev.c:1670 [inline]
call_netdevice_notifiers_extack net/core/dev.c:1682 [inline]
call_netdevice_notifiers net/core/dev.c:1696 [inline]
register_netdevice+0xeb9/0x12a0 net/core/dev.c:9240
tun_set_iff+0x812/0xe00 drivers/net/tun.c:2922
__tun_chr_ioctl+0x771/0x18a0 drivers/net/tun.c:3187
tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3470
do_vfs_ioctl+0x753/0x13f0 fs/ioctl.c:47
ksys_ioctl fs/ioctl.c:742 [inline]
__do_sys_ioctl fs/ioctl.c:749 [inline]
__se_sys_ioctl fs/ioctl.c:747 [inline]
__x64_sys_ioctl+0xe1/0x120 fs/ioctl.c:747
do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f3c25110969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3c23737038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3c25338160 RCX: 00007f3c25110969
RDX: 0000200000000140 RSI: 00000000400454ca RDI: 0000000000000003
RBP: 00007f3c25192ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3c25338160 R15: 00007ffd928eb6e8
Allocated by task 10205:
save_stack mm/kasan/common.c:70 [inline]
set_track mm/kasan/common.c:78 [inline]
__kasan_kmalloc+0x162/0x200 mm/kasan/common.c:529
kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:537
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+0xe2/0x270 mm/slub.c:2842
shmem_alloc_inode+0x1a/0x30 mm/shmem.c:3719
alloc_inode fs/inode.c:231 [inline]
new_inode_pseudo+0x62/0x210 fs/inode.c:966
new_inode+0x28/0x1e0 fs/inode.c:995
shmem_get_inode+0x107/0x630 mm/shmem.c:2252
shmem_symlink+0x9e/0x4d0 mm/shmem.c:3068
vfs_symlink+0x337/0x4c0 fs/namei.c:4276
do_symlinkat+0x103/0x3b0 fs/namei.c:4303
__do_sys_symlinkat fs/namei.c:4317 [inline]
__se_sys_symlinkat fs/namei.c:4314 [inline]
__x64_sys_symlinkat+0x7b/0x90 fs/namei.c:4314
do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1
Freed by task 10175:
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+0x1c3/0x280 mm/kasan/common.c:487
kasan_slab_free+0xe/0x10 mm/kasan/common.c:496
slab_free_hook mm/slub.c:1455 [inline]
slab_free_freelist_hook+0xb7/0x180 mm/slub.c:1494
slab_free mm/slub.c:3080 [inline]
kmem_cache_free+0x10c/0x2c0 mm/slub.c:3096
shmem_free_in_core_inode+0x90/0xb0 mm/shmem.c:3729
i_callback+0x4c/0x70 fs/inode.c:220
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch+0x446/0x980 kernel/rcu/tree.c:2167
rcu_core+0x4bd/0xbd0 kernel/rcu/tree.c:2387
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2396
__do_softirq+0x236/0x660 kernel/softirq.c:292
The buggy address belongs to the object at ffff8881e5343090
which belongs to the cache shmem_inode_cache of size 760
The buggy address is located 312 bytes inside of
760-byte region [ffff8881e5343090, ffff8881e5343388)
The buggy address belongs to the page:
page:ffffea000794d000 refcount:1 mapcount:0 mapping:ffff8881f5d03680 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5d03680
raw: 0000000000000000 0000000000120012 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, 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+0x35e/0x370 mm/page_alloc.c:2171
get_page_from_freelist+0x1296/0x1310 mm/page_alloc.c:3794
__alloc_pages_nodemask+0x202/0x4b0 mm/page_alloc.c:4894
alloc_slab_page+0x3c/0x3b0 mm/slub.c:343
allocate_slab mm/slub.c:1683 [inline]
new_slab+0x93/0x420 mm/slub.c:1749
new_slab_objects mm/slub.c:2505 [inline]
___slab_alloc+0x29e/0x420 mm/slub.c:2667
__slab_alloc+0x63/0xa0 mm/slub.c:2707
slab_alloc_node mm/slub.c:2792 [inline]
slab_alloc mm/slub.c:2837 [inline]
kmem_cache_alloc+0x12c/0x270 mm/slub.c:2842
shmem_alloc_inode+0x1a/0x30 mm/shmem.c:3719
alloc_inode fs/inode.c:231 [inline]
new_inode_pseudo+0x62/0x210 fs/inode.c:966
new_inode+0x28/0x1e0 fs/inode.c:995
shmem_get_inode+0x107/0x630 mm/shmem.c:2252
shmem_symlink+0x9e/0x4d0 mm/shmem.c:3068
vfs_symlink+0x337/0x4c0 fs/namei.c:4276
do_symlinkat+0x103/0x3b0 fs/namei.c:4303
__do_sys_symlinkat fs/namei.c:4317 [inline]
__se_sys_symlinkat fs/namei.c:4314 [inline]
__x64_sys_symlinkat+0x7b/0x90 fs/namei.c:4314
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+0x7e4/0x910 mm/page_alloc.c:1438
free_the_page mm/page_alloc.c:4956 [inline]
__free_pages+0x8c/0x110 mm/page_alloc.c:4962
kfree+0x1ca/0x260 mm/slub.c:4068
kvfree+0x4c/0x50 mm/util.c:625
bpf_check+0x8371/0x9cf0 kernel/bpf/verifier.c:9731
bpf_prog_load+0xa5f/0xe10 kernel/bpf/syscall.c:1724
__do_sys_bpf kernel/bpf/syscall.c:2891 [inline]
__se_sys_bpf+0x435/0x570 kernel/bpf/syscall.c:2849
__x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:2849
do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1
Memory state around the buggy address:
ffff8881e5343080: fc fc fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881e5343100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881e5343180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881e5343200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881e5343280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 1e04d7067 P4D 1e04d7067 PUD 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 10189 Comm: syz.8.3424 Tainted: G B 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010006
RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881e8dc5e80
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e53431c0
RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000fffff8a0
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e53431c0
FS: 00007f3c237376c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001e9bb1000 CR4: 00000000003406b0
DR0: 0100000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000090602
Call Trace:
call_timer_fn+0x3c/0x380 kernel/time/timer.c:1448
expire_timers kernel/time/timer.c:1488 [inline]
__run_timers+0x84b/0xb60 kernel/time/timer.c:1817
run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830
__do_softirq+0x236/0x660 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x197/0x1c0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:539 [inline]
smp_apic_timer_interrupt+0x11d/0x490 arch/x86/kernel/apic/apic.c:1161
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
RIP: 0010:__sanitizer_cov_trace_pc+0x3a/0x50 kernel/kcov.c:193
Code: 65 8b 15 95 0e a3 7e f7 c2 00 01 1f 00 74 02 5d c3 8b 91 00 0a 00 00 83 fa 02 75 f3 48 8b 91 08 0a 00 00 48 8b 32 48 8d 7e 01 <8b> 89 04 0a 00 00 48 39 cf 73 da 48 89 44 f2 08 48 89 3a 5d c3 90
RSP: 0018:ffff8881d71ff5f8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffff818dc260 RBX: ffff8881f5c02780 RCX: ffff8881e8dc5e80
RDX: ffffc90005555000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffff8881d71ff5f8 R08: dffffc0000000000 R09: 0000000000000003
R10: ffffed103ae3fec4 R11: 1ffff1103ae3fec4 R12: ffff8881f5c02780
R13: ffffffff81b2fee1 R14: 0000000000000dc0 R15: dffffc0000000000
__should_failslab+0x20/0x150 mm/failslab.c:18
should_failslab+0x9/0x20 mm/slab_common.c:1836
slab_pre_alloc_hook mm/slab.h:567 [inline]
slab_alloc_node mm/slub.c:2742 [inline]
slab_alloc mm/slub.c:2837 [inline]
__kmalloc+0x53/0x2f0 mm/slub.c:3909
kmalloc include/linux/slab.h:561 [inline]
kzalloc include/linux/slab.h:690 [inline]
new_dir fs/proc/proc_sysctl.c:973 [inline]
get_subdir fs/proc/proc_sysctl.c:1018 [inline]
__register_sysctl_table+0x921/0x1130 fs/proc/proc_sysctl.c:1361
register_net_sysctl+0x2c/0x40 net/sysctl_net.c:121
neigh_sysctl_register+0x998/0xa70 net/core/neighbour.c:3718
devinet_sysctl_register+0xaf/0x1e0 net/ipv4/devinet.c:2639
inetdev_init+0x28a/0x430 net/ipv4/devinet.c:277
inetdev_event+0x1f8/0x1030 net/ipv4/devinet.c:1545
notifier_call_chain kernel/notifier.c:98 [inline]
__raw_notifier_call_chain kernel/notifier.c:399 [inline]
raw_notifier_call_chain+0xa0/0x120 kernel/notifier.c:406
call_netdevice_notifiers_info net/core/dev.c:1670 [inline]
call_netdevice_notifiers_extack net/core/dev.c:1682 [inline]
call_netdevice_notifiers net/core/dev.c:1696 [inline]
register_netdevice+0xeb9/0x12a0 net/core/dev.c:9240
tun_set_iff+0x812/0xe00 drivers/net/tun.c:2922
__tun_chr_ioctl+0x771/0x18a0 drivers/net/tun.c:3187
tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3470
do_vfs_ioctl+0x753/0x13f0 fs/ioctl.c:47
ksys_ioctl fs/ioctl.c:742 [inline]
__do_sys_ioctl fs/ioctl.c:749 [inline]
__se_sys_ioctl fs/ioctl.c:747 [inline]
__x64_sys_ioctl+0xe1/0x120 fs/ioctl.c:747
do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f3c25110969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3c23737038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3c25338160 RCX: 00007f3c25110969
RDX: 0000200000000140 RSI: 00000000400454ca RDI: 0000000000000003
RBP: 00007f3c25192ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3c25338160 R15: 00007ffd928eb6e8
Modules linked in:
CR2: 0000000000000000
---[ end trace 57b2ffdd4cb8241e ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010006
RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881e8dc5e80
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e53431c0
RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000fffff8a0
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e53431c0
FS: 00007f3c237376c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001e9bb1000 CR4: 00000000003406b0
DR0: 0100000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000090602
----------------
Code disassembly (best guess):
0: 65 8b 15 95 0e a3 7e mov %gs:0x7ea30e95(%rip),%edx # 0x7ea30e9c
7: f7 c2 00 01 1f 00 test $0x1f0100,%edx
d: 74 02 je 0x11
f: 5d pop %rbp
10: c3 ret
11: 8b 91 00 0a 00 00 mov 0xa00(%rcx),%edx
17: 83 fa 02 cmp $0x2,%edx
1a: 75 f3 jne 0xf
1c: 48 8b 91 08 0a 00 00 mov 0xa08(%rcx),%rdx
23: 48 8b 32 mov (%rdx),%rsi
26: 48 8d 7e 01 lea 0x1(%rsi),%rdi
* 2a: 8b 89 04 0a 00 00 mov 0xa04(%rcx),%ecx <-- trapping instruction
30: 48 39 cf cmp %rcx,%rdi
33: 73 da jae 0xf
35: 48 89 44 f2 08 mov %rax,0x8(%rdx,%rsi,8)
3a: 48 89 3a mov %rdi,(%rdx)
3d: 5d pop %rbp
3e: c3 ret
3f: 90 nop