==================================================================
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+0x759/0xb60 kernel/time/timer.c:1817
Write of size 8 at addr ffff8881e09231c8 by task syz.2.835/3309

CPU: 0 PID: 3309 Comm: syz.2.835 Tainted: G        W         5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <IRQ>
 __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_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+0x759/0xb60 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
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:180
Code: 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 be 0c 00 00 00 48 c7 c7 00 96 d1 85 e8 6b f2 2d 00 5d c3 00 00 90 90 00 00 90 90 00 55 <48> 89 e5 48 8b 45 08 65 48 8b 0d 90 0e a3 7e 65 8b 15 95 0e a3 7e
RSP: 0018:ffff8881de1cf6f0 EFLAGS: 00000297 ORIG_RAX: ffffffffffffff13
RAX: ffffffff8423bf22 RBX: ffffffff84c4e902 RCX: 0000000000000000
RDX: ffff8881e7854ec0 RSI: 000000000000000b RDI: 0000000000000000
RBP: ffff8881de1cf790 R08: dffffc0000000000 R09: ffff8881de1cf660
R10: ffffed103bc39ecf R11: 1ffff1103bc39ecc R12: 000000000000000b
R13: ffff8881de1cf904 R14: ffff8881de1cf900 R15: ffff8881de1cf90b
 snprintf+0xd7/0x120 lib/vsprintf.c:2734
 proc_flush_task_mnt fs/proc/base.c:3239 [inline]
 proc_flush_task+0x2a2/0x470 fs/proc/base.c:3301
 release_task+0xad/0x11e0 kernel/exit.c:249
 exit_notify kernel/exit.c:736 [inline]
 do_exit+0x19b4/0x2660 kernel/exit.c:882
 do_group_exit+0x13e/0x300 kernel/exit.c:984
 get_signal+0xdee/0x13d0 kernel/signal.c:2738
 do_signal+0xad/0xda0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0xc4/0x1b0 arch/x86/entry/common.c:159
 prepare_exit_to_usermode+0x18e/0x1f0 arch/x86/entry/common.c:194
 syscall_return_slowpath+0x61/0x80 arch/x86/entry/common.c:274
 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:346
RIP: 0033:0x7fd2786301c9
Code: bf 08 00 48 8d 3d dc bf 08 00 e8 e2 28 f6 ff 66 90 b8 ea ff ff ff 48 85 ff 74 2c 48 85 d2 74 27 49 89 c8 b8 b3 01 00 00 0f 05 <48> 85 c0 7c 18 74 01 c3 31 ed 48 83 e4 f0 4c 89 c7 ff d2 48 89 c7
RSP: 002b:00007fd276c011c0 EFLAGS: 00000202 ORIG_RAX: 00000000000001b3
RAX: 0000000000000000 RBX: 00007fd2785b25b0 RCX: 00007fd2786301c9
RDX: 00007fd2785b25b0 RSI: 0000000000000058 RDI: 00007ffedf068f40
RBP: 00007fd276c016c0 R08: 00007fd276c016c0 R09: 00007ffedf069027
R10: 0000000000000008 R11: 0000000000000202 R12: ffffffffffffffa8
R13: 000000000000000b R14: 00007ffedf068f40 R15: 00007ffedf069028

The buggy address belongs to the page:
page:ffffea00078248c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x8000000000000000()
raw: 8000000000000000 ffffea0007824888 ffffea00077d8208 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO)
 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_pages include/linux/gfp.h:503 [inline]
 __alloc_pages_node include/linux/gfp.h:516 [inline]
 alloc_pages_node include/linux/gfp.h:530 [inline]
 __vmalloc_area_node mm/vmalloc.c:-1 [inline]
 __vmalloc_node_range+0x36a/0x6e0 mm/vmalloc.c:2499
 vmalloc_user+0x73/0x80 mm/vmalloc.c:2629
 kcov_mmap+0x2b/0x120 kernel/kcov.c:450
 call_mmap include/linux/fs.h:1996 [inline]
 mmap_region+0x101b/0x15a0 mm/mmap.c:1812
 do_mmap+0x826/0xd90 mm/mmap.c:1581
 do_mmap_pgoff include/linux/mm.h:2480 [inline]
 vm_mmap_pgoff+0x195/0x230 mm/util.c:528
 ksys_mmap_pgoff+0x16f/0x1e0 mm/mmap.c:1631
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:97 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:88 [inline]
 __x64_sys_mmap+0xfa/0x110 arch/x86/kernel/sys_x86_64.c:88
 do_syscall_64+0xcf/0x170 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_pcp_prepare mm/page_alloc.c:1233 [inline]
 free_unref_page_prepare+0x2a9/0x3a0 mm/page_alloc.c:3085
 free_unref_page mm/page_alloc.c:3134 [inline]
 free_the_page mm/page_alloc.c:4954 [inline]
 __free_pages+0xaa/0x110 mm/page_alloc.c:4962
 __vunmap+0x76a/0x8a0 mm/vmalloc.c:2260
 __vfree mm/vmalloc.c:2308 [inline]
 vfree+0x61/0x90 mm/vmalloc.c:2338
 kcov_mmap+0x8c/0x120 kernel/kcov.c:474
 call_mmap include/linux/fs.h:1996 [inline]
 mmap_region+0x101b/0x15a0 mm/mmap.c:1812
 do_mmap+0x826/0xd90 mm/mmap.c:1581
 do_mmap_pgoff include/linux/mm.h:2480 [inline]
 vm_mmap_pgoff+0x195/0x230 mm/util.c:528
 ksys_mmap_pgoff+0x16f/0x1e0 mm/mmap.c:1631
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:97 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:88 [inline]
 __x64_sys_mmap+0xfa/0x110 arch/x86/kernel/sys_x86_64.c:88
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Memory state around the buggy address:
 ffff8881e0923080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881e0923100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881e0923180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff8881e0923200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881e0923280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 1e673f067 P4D 1e673f067 PUD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 3309 Comm: syz.2.835 Tainted: G    B   W         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: 00010206
RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881e7854ec0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e09231c0
RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffb2b0
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e09231c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001ec7e9000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 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
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:180
Code: 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 be 0c 00 00 00 48 c7 c7 00 96 d1 85 e8 6b f2 2d 00 5d c3 00 00 90 90 00 00 90 90 00 55 <48> 89 e5 48 8b 45 08 65 48 8b 0d 90 0e a3 7e 65 8b 15 95 0e a3 7e
RSP: 0018:ffff8881de1cf6f0 EFLAGS: 00000297 ORIG_RAX: ffffffffffffff13
RAX: ffffffff8423bf22 RBX: ffffffff84c4e902 RCX: 0000000000000000
RDX: ffff8881e7854ec0 RSI: 000000000000000b RDI: 0000000000000000
RBP: ffff8881de1cf790 R08: dffffc0000000000 R09: ffff8881de1cf660
R10: ffffed103bc39ecf R11: 1ffff1103bc39ecc R12: 000000000000000b
R13: ffff8881de1cf904 R14: ffff8881de1cf900 R15: ffff8881de1cf90b
 snprintf+0xd7/0x120 lib/vsprintf.c:2734
 proc_flush_task_mnt fs/proc/base.c:3239 [inline]
 proc_flush_task+0x2a2/0x470 fs/proc/base.c:3301
 release_task+0xad/0x11e0 kernel/exit.c:249
 exit_notify kernel/exit.c:736 [inline]
 do_exit+0x19b4/0x2660 kernel/exit.c:882
 do_group_exit+0x13e/0x300 kernel/exit.c:984
 get_signal+0xdee/0x13d0 kernel/signal.c:2738
 do_signal+0xad/0xda0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0xc4/0x1b0 arch/x86/entry/common.c:159
 prepare_exit_to_usermode+0x18e/0x1f0 arch/x86/entry/common.c:194
 syscall_return_slowpath+0x61/0x80 arch/x86/entry/common.c:274
 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:346
RIP: 0033:0x7fd2786301c9
Code: bf 08 00 48 8d 3d dc bf 08 00 e8 e2 28 f6 ff 66 90 b8 ea ff ff ff 48 85 ff 74 2c 48 85 d2 74 27 49 89 c8 b8 b3 01 00 00 0f 05 <48> 85 c0 7c 18 74 01 c3 31 ed 48 83 e4 f0 4c 89 c7 ff d2 48 89 c7
RSP: 002b:00007fd276c011c0 EFLAGS: 00000202 ORIG_RAX: 00000000000001b3
RAX: 0000000000000000 RBX: 00007fd2785b25b0 RCX: 00007fd2786301c9
RDX: 00007fd2785b25b0 RSI: 0000000000000058 RDI: 00007ffedf068f40
RBP: 00007fd276c016c0 R08: 00007fd276c016c0 R09: 00007ffedf069027
R10: 0000000000000008 R11: 0000000000000202 R12: ffffffffffffffa8
R13: 000000000000000b R14: 00007ffedf068f40 R15: 00007ffedf069028
Modules linked in:
CR2: 0000000000000000
---[ end trace 5a7335bedd73690c ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010206
RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881e7854ec0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e09231c0
RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffb2b0
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e09231c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001ec7e9000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600