==================================================================
BUG: KASAN: out-of-bounds in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: out-of-bounds in atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline]
BUG: KASAN: out-of-bounds in put_bh include/linux/buffer_head.h:301 [inline]
BUG: KASAN: out-of-bounds in end_buffer_read_sync+0xc1/0xd0 fs/buffer.c:161
Write of size 4 at addr ffffc900049ff660 by task kworker/u8:6/1143
CPU: 0 UID: 0 PID: 1143 Comm: kworker/u8:6 Not tainted 6.14.0-next-20250404-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: loop4 loop_workfn
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0x16e/0x5b0 mm/kasan/report.c:521
kasan_report+0x143/0x180 mm/kasan/report.c:634
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x28f/0x2a0 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline]
put_bh include/linux/buffer_head.h:301 [inline]
end_buffer_read_sync+0xc1/0xd0 fs/buffer.c:161
end_bio_bh_io_sync+0xbf/0x120 fs/buffer.c:2748
blk_update_request+0x5e5/0x1160 block/blk-mq.c:983
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1145
blk_complete_reqs block/blk-mq.c:1220 [inline]
blk_done_softirq+0x100/0x150 block/blk-mq.c:1225
handle_softirqs+0x2d6/0x9b0 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xfb/0x220 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
sysvec_call_function_single+0xa3/0xc0 arch/x86/kernel/smp.c:266
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 fa 2a 6b f5 48 89 df e8 32 d4 6b f5 e8 4d 6a 97 f5 fb bf 01 00 00 00 42 b5 5c f5 65 8b 05 eb 2b 35 07 85 c0 74 06 5b c3 cc cc cc cc
RSP: 0018:ffffc90003ebf650 EFLAGS: 00000286
RAX: 622b9dfd72614000 RBX: ffff8880255ad8c8 RCX: 0000000000000006
RDX: 0000000000000006 RSI: ffffffff8e6a4c4b RDI: 0000000000000001
RBP: ffffc90003ebfb10 R08: ffffffff905ffd37 R09: 1ffffffff20bffa6
R10: dffffc0000000000 R11: fffffbfff20bffa7 R12: ffff8880255ad968
R13: ffff8880255ad970 R14: ffff888079e43770 R15: dffffc0000000000
spin_unlock_irq include/linux/spinlock.h:401 [inline]
loop_process_work+0x20b4/0x21d0 drivers/block/loop.c:1994
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
The buggy address belongs to the virtual mapping at
[ffffc900049f8000, ffffc90004a01000) created by:
copy_process+0x5dc/0x3d10 kernel/fork.c:2259
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x48 pfn:0x34f40
memcg:ffff888034480382
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000048 0000000000000000 00000001ffffffff ffff888034480382
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_ZERO|__GFP_NOWARN), pid 6377, tgid 6377 (syz.2.103), ts 135740063564, free_ts 133412138412
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1718
prep_new_page mm/page_alloc.c:1726 [inline]
get_page_from_freelist+0x356d/0x3700 mm/page_alloc.c:3655
__alloc_frozen_pages_noprof+0x211/0x5b0 mm/page_alloc.c:4937
alloc_pages_mpol+0x339/0x690 mm/mempolicy.c:2302
alloc_frozen_pages_noprof mm/mempolicy.c:2373 [inline]
alloc_pages_noprof+0x121/0x190 mm/mempolicy.c:2393
vm_area_alloc_pages mm/vmalloc.c:3591 [inline]
__vmalloc_area_node mm/vmalloc.c:3669 [inline]
__vmalloc_node_range_noprof+0x9cb/0x1390 mm/vmalloc.c:3844
__vmalloc_node_noprof+0x80/0xa0 mm/vmalloc.c:3907
alloc_thread_stack_node kernel/fork.c:314 [inline]
dup_task_struct+0x3f7/0x870 kernel/fork.c:1136
copy_process+0x5dc/0x3d10 kernel/fork.c:2259
kernel_clone+0x242/0x930 kernel/fork.c:2844
__do_sys_clone3 kernel/fork.c:3148 [inline]
__se_sys_clone3+0x348/0x380 kernel/fork.c:3127
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5966 tgid 5966 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1262 [inline]
free_unref_folios+0xe0e/0x17f0 mm/page_alloc.c:2739
folios_put_refs+0x70a/0x800 mm/swap.c:992
folio_batch_release include/linux/pagevec.h:101 [inline]
truncate_inode_pages_range+0x462/0x10e0 mm/truncate.c:379
kill_bdev block/bdev.c:91 [inline]
blkdev_flush_mapping+0x108/0x270 block/bdev.c:674
blkdev_put_whole block/bdev.c:681 [inline]
bdev_release+0x460/0x700 block/bdev.c:1106
blkdev_release+0x15/0x20 block/fops.c:660
__fput+0x3e9/0x9f0 fs/file_table.c:465
task_work_run+0x251/0x310 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffffc900049ff500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc900049ff580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc900049ff600: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00
^
ffffc900049ff680: 00 00 00 f2 f2 f2 f2 f2 00 f2 f2 f2 01 f3 f3 f3
ffffc900049ff700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
0: 90 nop
1: f3 0f 1e fa endbr64
5: 53 push %rbx
6: 48 89 fb mov %rdi,%rbx
9: 48 83 c7 18 add $0x18,%rdi
d: 48 8b 74 24 08 mov 0x8(%rsp),%rsi
12: e8 fa 2a 6b f5 call 0xf56b2b11
17: 48 89 df mov %rbx,%rdi
1a: e8 32 d4 6b f5 call 0xf56bd451
1f: e8 4d 6a 97 f5 call 0xf5976a71
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 42 b5 5c f5 call 0xf55cb571 <-- trapping instruction
2f: 65 8b 05 eb 2b 35 07 mov %gs:0x7352beb(%rip),%eax # 0x7352c21
36: 85 c0 test %eax,%eax
38: 74 06 je 0x40
3a: 5b pop %rbx
3b: c3 ret
3c: cc int3
3d: cc int3
3e: cc int3
3f: cc int3