==================================================================
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:304 [inline]
BUG: KASAN: out-of-bounds in end_buffer_read_sync+0xc3/0xe0 fs/buffer.c:161
Write of size 4 at addr ffffc9000b5e7700 by task syz.0.559/8593
CPU: 0 UID: 0 PID: 8593 Comm: syz.0.559 Not tainted 6.16.0-rc5-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0xd2/0x2b0 mm/kasan/report.c:521
kasan_report+0x118/0x150 mm/kasan/report.c:634
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x2b0/0x2c0 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:304 [inline]
end_buffer_read_sync+0xc3/0xe0 fs/buffer.c:161
end_bio_bh_io_sync+0xbd/0x120 fs/buffer.c:2783
blk_update_request+0x5eb/0xe70 block/blk-mq.c:987
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1149
blk_complete_reqs block/blk-mq.c:1224 [inline]
blk_done_softirq+0x10a/0x160 block/blk-mq.c:1229
handle_softirqs+0x286/0x870 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xca/0x1f0 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:finish_task_switch+0x26b/0x950 kernel/sched/core.c:5269
Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 e9 27 05 00 00 4c 8b 75 d0 4c 89 e7 e8 2f a9 df 09 e8 ca c6 35 00 fb 4c 8b 65 c0 <49> 8d bc 24 18 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc9000518f518 EFLAGS: 00000286
RAX: 8bb8cc57140a9100 RBX: 0000000000000000 RCX: 8bb8cc57140a9100
RDX: 0000000000000007 RSI: ffffffff8d997600 RDI: ffffffff8be29580
RBP: ffffc9000518f570 R08: ffffffff8fa1e5f7 R09: 1ffffffff1f43cbe
R10: dffffc0000000000 R11: fffffbfff1f43cbf R12: ffff888026728000
R13: dffffc0000000000 R14: ffff888025075a00 R15: ffff8880b863ab58
context_switch kernel/sched/core.c:5404 [inline]
__schedule+0x16fd/0x4d00 kernel/sched/core.c:6790
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7113
irqentry_exit+0x6f/0x90 kernel/entry/common.c:307
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
RIP: 0010:mm_account_fault mm/memory.c:6254 [inline]
RIP: 0010:handle_mm_fault+0x520/0x8e0 mm/memory.c:6407
Code: b4 ff 65 48 ff 05 f8 cc 95 10 48 8b 7c 24 48 be 17 00 00 00 e8 21 6c ff ff 89 de 81 e6 73 08 00 00 31 ff e8 42 90 b4 ff 89 d8 <25> 73 08 00 00 74 22 e8 f4 8b b4 ff eb 05 e8 ed 8b b4 ff 89 d8 48
RSP: 0018:ffffc9000518f900 EFLAGS: 00000297
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: ffff888026728000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000041 R08: ffffffff8fa1e5f7 R09: 1ffffffff1f43cbe
R10: dffffc0000000000 R11: fffffbfff1f43cbf R12: 0000000000000215
R13: ffff888026728000 R14: 0000000000000000 R15: 1ffff11004ce50b2
do_user_addr_fault+0x764/0x1390 arch/x86/mm/fault.c:1387
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
RIP: 0010:raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline]
RIP: 0010:copy_to_user_iter lib/iov_iter.c:25 [inline]
RIP: 0010:iterate_ubuf include/linux/iov_iter.h:30 [inline]
RIP: 0010:iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
RIP: 0010:iterate_and_advance include/linux/iov_iter.h:328 [inline]
RIP: 0010:_copy_to_iter+0x247/0x16f0 lib/iov_iter.c:185
Code: e5 01 00 00 e8 2a e5 00 fd 48 8b 5c 24 50 48 89 df 4c 8b 7c 24 10 44 89 fe e8 35 6a 64 fd 0f 01 cb 4c 89 ef 4c 89 f9 48 89 de a4 0f 1f 00 0f 01 ca 4c 89 f3 49 29 cf 49 be 00 00 00 00 00 fc
RSP: 0018:ffffc9000518fb20 EFLAGS: 00050256
RAX: ffffffff84bf4001 RBX: ffffc9000518fd20 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffffc9000518fd20 RDI: 0000200000060000
RBP: ffffc9000518fc70 R08: ffffc9000518fd5f R09: 1ffff92000a31fab
R10: dffffc0000000000 R11: fffff52000a31fac R12: 1ffff92000a31fc5
R13: 0000200000060000 R14: ffffc9000518fe38 R15: 0000000000000040
copy_to_iter include/linux/uio.h:220 [inline]
get_random_bytes_user+0x1a0/0x380 drivers/char/random.c:473
__do_sys_getrandom drivers/char/random.c:1416 [inline]
__se_sys_getrandom drivers/char/random.c:1390 [inline]
__x64_sys_getrandom+0x16d/0x260 drivers/char/random.c:1390
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fafe918e929
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:00007fafe9f17038 EFLAGS: 00000246 ORIG_RAX: 000000000000013e
RAX: ffffffffffffffda RBX: 00007fafe93b6080 RCX: 00007fafe918e929
RDX: 0000000000000000 RSI: 00000000ffffff9a RDI: 0000200000000240
RBP: 00007fafe9210b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fafe93b6080 R15: 00007ffd5df164a8
The buggy address belongs to the virtual mapping at
[ffffc9000b5e0000, ffffc9000b5e9000) created by:
copy_process+0x544/0x3b80 kernel/fork.c:1999
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x16 pfn:0x7b721
memcg:ffff888032ae7682
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000016 0000000000000000 00000001ffffffff ffff888032ae7682
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_ZERO|__GFP_NOWARN), pid 7228, tgid 7228 (syz-executor), ts 398118854708, free_ts 396644425611
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
prep_new_page mm/page_alloc.c:1712 [inline]
get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
alloc_frozen_pages_noprof mm/mempolicy.c:2490 [inline]
alloc_pages_noprof+0xa9/0x190 mm/mempolicy.c:2510
vm_area_alloc_pages mm/vmalloc.c:3634 [inline]
__vmalloc_area_node mm/vmalloc.c:3712 [inline]
__vmalloc_node_range_noprof+0x97d/0x12f0 mm/vmalloc.c:3885
__vmalloc_node_noprof+0xc2/0x110 mm/vmalloc.c:3948
alloc_thread_stack_node kernel/fork.c:317 [inline]
dup_task_struct+0x3e7/0x860 kernel/fork.c:877
copy_process+0x544/0x3b80 kernel/fork.c:1999
kernel_clone+0x21e/0x870 kernel/fork.c:2599
__do_sys_clone kernel/fork.c:2742 [inline]
__se_sys_clone kernel/fork.c:2726 [inline]
__x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2726
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 1067 tgid 1067 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1248 [inline]
__free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706
pagetable_free include/linux/mm.h:2879 [inline]
pagetable_dtor_free include/linux/mm.h:2977 [inline]
__tlb_remove_table+0x2d2/0x3b0 include/asm-generic/tlb.h:220
__tlb_remove_table_free mm/mmu_gather.c:227 [inline]
tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:290
rcu_do_batch kernel/rcu/tree.c:2576 [inline]
rcu_core+0xca8/0x1710 kernel/rcu/tree.c:2832
handle_softirqs+0x286/0x870 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
Memory state around the buggy address:
ffffc9000b5e7600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc9000b5e7680: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
>ffffc9000b5e7700: 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 00 f2 f2 f2
^
ffffc9000b5e7780: 01 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
ffffc9000b5e7800: 00 00 00 00 f1 f1 f1 f1 00 f3 f3 f3 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
0: 0f 84 3c 01 00 00 je 0x142
6: 48 85 db test %rbx,%rbx
9: 0f 85 63 01 00 00 jne 0x172
f: e9 27 05 00 00 jmp 0x53b
14: 4c 8b 75 d0 mov -0x30(%rbp),%r14
18: 4c 89 e7 mov %r12,%rdi
1b: e8 2f a9 df 09 call 0x9dfa94f
20: e8 ca c6 35 00 call 0x35c6ef
25: fb sti
26: 4c 8b 65 c0 mov -0x40(%rbp),%r12
* 2a: 49 8d bc 24 18 16 00 lea 0x1618(%r12),%rdi <-- trapping instruction
31: 00
32: 48 89 f8 mov %rdi,%rax
35: 48 c1 e8 03 shr $0x3,%rax
39: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax
3e: 84 c0 test %al,%al