RBP: 00007fcacaceb090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000002
R13: 00007fcacc50a038 R14: 00007fcacc509fa0 R15: 00007fff8485c208
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:167 [inline]
BUG: KASAN: use-after-free in __refcount_sub_and_test include/linux/refcount.h:272 [inline]
BUG: KASAN: use-after-free in __refcount_dec_and_test include/linux/refcount.h:315 [inline]
BUG: KASAN: use-after-free in refcount_dec_and_test include/linux/refcount.h:333 [inline]
BUG: KASAN: use-after-free in kref_put include/linux/kref.h:64 [inline]
BUG: KASAN: use-after-free in anon_vma_name_put include/linux/mm_inline.h:375 [inline]
BUG: KASAN: use-after-free in free_anon_vma_name include/linux/mm_inline.h:406 [inline]
BUG: KASAN: use-after-free in vm_area_free_no_check+0x7e/0x140 kernel/fork.c:406
Write of size 4 at addr ffff88811efc5be9 by task syz.2.235/1065
CPU: 1 PID: 1065 Comm: syz.2.235 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
__dump_stack+0x21/0x30 lib/dump_stack.c:88
dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:427 [inline]
kasan_report+0xf1/0x140 mm/kasan/report.c:444
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189
__kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37
instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:167 [inline]
__refcount_sub_and_test include/linux/refcount.h:272 [inline]
__refcount_dec_and_test include/linux/refcount.h:315 [inline]
refcount_dec_and_test include/linux/refcount.h:333 [inline]
kref_put include/linux/kref.h:64 [inline]
anon_vma_name_put include/linux/mm_inline.h:375 [inline]
free_anon_vma_name include/linux/mm_inline.h:406 [inline]
vm_area_free_no_check+0x7e/0x140 kernel/fork.c:406
vm_area_free kernel/fork.c:419 [inline]
dup_mmap kernel/fork.c:682 [inline]
dup_mm kernel/fork.c:1522 [inline]
copy_mm+0xe90/0x13c0 kernel/fork.c:1574
copy_process+0x117c/0x3250 kernel/fork.c:2348
kernel_clone+0x233/0x960 kernel/fork.c:2737
__do_sys_clone kernel/fork.c:2863 [inline]
__se_sys_clone kernel/fork.c:2847 [inline]
__x64_sys_clone+0x198/0x210 kernel/fork.c:2847
x64_sys_call+0x41f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:57
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fcacc290819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcacaceafd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fcacc509fa0 RCX: 00007fcacc290819
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000005000000
RBP: 00007fcacaceb090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000002
R13: 00007fcacc50a038 R14: 00007fcacc509fa0 R15: 00007fff8485c208
Allocated by task 1011:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:433 [inline]
__kasan_slab_alloc+0xbd/0xf0 mm/kasan/common.c:466
kasan_slab_alloc include/linux/kasan.h:217 [inline]
slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550
slab_alloc_node mm/slub.c:3245 [inline]
slab_alloc mm/slub.c:3255 [inline]
kmem_cache_alloc+0xf7/0x260 mm/slub.c:3260
vm_area_dup+0x26/0x210 kernel/fork.c:368
dup_mmap kernel/fork.c:602 [inline]
dup_mm kernel/fork.c:1522 [inline]
copy_mm+0x947/0x13c0 kernel/fork.c:1574
copy_process+0x117c/0x3250 kernel/fork.c:2348
kernel_clone+0x233/0x960 kernel/fork.c:2737
__do_sys_clone kernel/fork.c:2863 [inline]
__se_sys_clone kernel/fork.c:2847 [inline]
__x64_sys_clone+0x198/0x210 kernel/fork.c:2847
x64_sys_call+0x41f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:57
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Freed by task 25:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
kasan_slab_free include/linux/kasan.h:193 [inline]
slab_free_hook mm/slub.c:1728 [inline]
slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754
slab_free mm/slub.c:3526 [inline]
kmem_cache_free+0x100/0x320 mm/slub.c:3544
__free_vm_area_struct+0x1c/0x20 kernel/fork.c:390
rcu_do_batch+0x532/0xbe0 kernel/rcu/tree.c:2523
rcu_core+0x5ee/0xf80 kernel/rcu/tree.c:2763
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2776
handle_softirqs+0x250/0x560 kernel/softirq.c:583
run_ksoftirqd+0x28/0x40 kernel/softirq.c:959
smpboot_thread_fn+0x45a/0x8c0 kernel/smpboot.c:164
kthread+0x411/0x500 kernel/kthread.c:337
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
__kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
__call_rcu_common kernel/rcu/tree.c:3011 [inline]
call_rcu+0x10b/0xf80 kernel/rcu/tree.c:3129
free_vm_area_struct kernel/fork.c:395 [inline]
vm_area_free_no_check+0x10e/0x140 kernel/fork.c:409
vm_area_free+0x56/0x60 kernel/fork.c:419
remove_vma mm/mmap.c:191 [inline]
exit_mmap+0x4e6/0x8b0 mm/mmap.c:3254
__mmput+0x93/0x320 kernel/fork.c:1180
mmput+0x50/0x150 kernel/fork.c:1203
exit_mm kernel/exit.c:554 [inline]
do_exit+0x9f2/0x27e0 kernel/exit.c:876
do_group_exit+0x141/0x310 kernel/exit.c:1003
get_signal+0x66a/0x1480 kernel/signal.c:2907
arch_do_signal_or_restart+0xdf/0x11c0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0xa7/0xe0 kernel/entry/common.c:178
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214
irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:320
irqentry_exit+0x12/0x40 kernel/entry/common.c:411
exc_page_fault+0x5e/0xb0 arch/x86/mm/fault.c:1563
asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:606
The buggy address belongs to the object at ffff88811efc5b90
which belongs to the cache vm_area_struct of size 232
The buggy address is located 89 bytes inside of
232-byte region [ffff88811efc5b90, ffff88811efc5c78)
The buggy address belongs to the page:
page:ffffea00047bf140 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11efc5
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 0000000000000000 dead000000000122 ffff888100186180
raw: 0000000000000000 00000000000d000d 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 1011, ts 54201572025, free_ts 54166085616
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605
prep_new_page+0x1c/0x110 mm/page_alloc.c:2611
get_page_from_freelist+0x2d3a/0x2dc0 mm/page_alloc.c:4485
__alloc_pages+0x1a2/0x460 mm/page_alloc.c:5822
alloc_slab_page mm/slub.c:-1 [inline]
allocate_slab mm/slub.c:1937 [inline]
new_slab+0xa1/0x4d0 mm/slub.c:2000
___slab_alloc+0x381/0x810 mm/slub.c:3033
__slab_alloc+0x49/0x90 mm/slub.c:3120
slab_alloc_node mm/slub.c:3211 [inline]
slab_alloc mm/slub.c:3255 [inline]
kmem_cache_alloc+0x138/0x260 mm/slub.c:3260
vm_area_dup+0x26/0x210 kernel/fork.c:368
dup_mmap kernel/fork.c:602 [inline]
dup_mm kernel/fork.c:1522 [inline]
copy_mm+0x947/0x13c0 kernel/fork.c:1574
copy_process+0x117c/0x3250 kernel/fork.c:2348
kernel_clone+0x233/0x960 kernel/fork.c:2737
__do_sys_clone kernel/fork.c:2863 [inline]
__se_sys_clone kernel/fork.c:2847 [inline]
__x64_sys_clone+0x198/0x210 kernel/fork.c:2847
x64_sys_call+0x41f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:57
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
free_pages_prepare mm/page_alloc.c:1472 [inline]
free_pcp_prepare mm/page_alloc.c:1544 [inline]
free_unref_page_prepare+0x542/0x550 mm/page_alloc.c:3534
free_unref_page_list+0x13a/0x9d0 mm/page_alloc.c:3671
release_pages+0x1006/0x1060 mm/swap.c:1015
free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:320
tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
tlb_flush_mmu mm/mmu_gather.c:247 [inline]
tlb_finish_mmu+0x17e/0x310 mm/mmu_gather.c:338
exit_mmap+0x43b/0x8b0 mm/mmap.c:3248
__mmput+0x93/0x320 kernel/fork.c:1180
mmput+0x50/0x150 kernel/fork.c:1203
exit_mm kernel/exit.c:554 [inline]
do_exit+0x9f2/0x27e0 kernel/exit.c:876
do_group_exit+0x141/0x310 kernel/exit.c:1003
__do_sys_exit_group kernel/exit.c:1014 [inline]
__se_sys_exit_group kernel/exit.c:1012 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1012
x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Memory state around the buggy address:
ffff88811efc5a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811efc5b00: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
>ffff88811efc5b80: fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811efc5c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
ffff88811efc5c80: fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 1065 at lib/refcount.c:28 refcount_warn_saturate+0x120/0x1a0 lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 1065 Comm: syz.2.235 Tainted: G B syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:refcount_warn_saturate+0x120/0x1a0 lib/refcount.c:28
Code: 04 01 48 c7 c7 80 60 63 85 e8 4c c1 5a 02 0f 0b eb c3 e8 83 9c 19 ff c6 05 1f fc 95 04 01 48 c7 c7 e0 60 63 85 e8 30 c1 5a 02 <0f> 0b eb a7 e8 67 9c 19 ff c6 05 00 fc 95 04 01 48 c7 c7 20 60 63
RSP: 0018:ffffc90000c47928 EFLAGS: 00010246
RAX: 081546e5c4273200 RBX: 0000000000000003 RCX: ffff8881168f13c0
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc90000c47938 R08: ffff8881f7032f3f R09: 1ffff1103ee065e7
R10: dffffc0000000000 R11: ffffed103ee065e8 R12: 00000000811ef2dd
R13: ffff88811c6c3d58 R14: 0000000000000003 R15: ffff88811efc5be9
FS: 00007fcacaceb6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3042cc02f8 CR3: 0000000150e8f000 CR4: 00000000003506b0
DR0: 0000000000000002 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
__refcount_sub_and_test include/linux/refcount.h:283 [inline]
__refcount_dec_and_test include/linux/refcount.h:315 [inline]
refcount_dec_and_test include/linux/refcount.h:333 [inline]
kref_put include/linux/kref.h:64 [inline]
anon_vma_name_put include/linux/mm_inline.h:375 [inline]
free_anon_vma_name include/linux/mm_inline.h:406 [inline]
vm_area_free_no_check+0x132/0x140 kernel/fork.c:406
vm_area_free kernel/fork.c:419 [inline]
dup_mmap kernel/fork.c:682 [inline]
dup_mm kernel/fork.c:1522 [inline]
copy_mm+0xe90/0x13c0 kernel/fork.c:1574
copy_process+0x117c/0x3250 kernel/fork.c:2348
kernel_clone+0x233/0x960 kernel/fork.c:2737
__do_sys_clone kernel/fork.c:2863 [inline]
__se_sys_clone kernel/fork.c:2847 [inline]
__x64_sys_clone+0x198/0x210 kernel/fork.c:2847
x64_sys_call+0x41f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:57
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fcacc290819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcacaceafd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fcacc509fa0 RCX: 00007fcacc290819
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000005000000
RBP: 00007fcacaceb090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000002
R13: 00007fcacc50a038 R14: 00007fcacc509fa0 R15: 00007fff8485c208
---[ end trace c439d87f54f41fd1 ]---