audit: type=1400 audit(1751466197.558:11): avc: denied { watch_reads } for pid=4985 comm="syz-executor.1" path="/syzkaller-testdir109614847/syzkaller.kecApY/34/file0" dev="sda" ino=16000 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1
==================================================================
BUG: KASAN: slab-use-after-free in flush_tlb_func+0x24d/0x560
Write of size 8 at addr ffff888018605140 by task kauditd/31
CPU: 1 UID: 0 PID: 31 Comm: kauditd Not tainted 6.16.0-rc4-next-20250702 #1 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
dump_stack_lvl+0xca/0x120
print_report+0xcb/0x670
kasan_report+0xca/0x100
kasan_check_range+0x39/0x1b0
flush_tlb_func+0x24d/0x560
__flush_smp_call_function_queue+0x20d/0x740
__sysvec_call_function_single+0x6d/0x360
sysvec_call_function_single+0xa1/0xc0
asm_sysvec_call_function_single+0x1a/0x20
RIP: 0010:console_flush_all+0x8c1/0xb70
Code: 01 4c 89 e8 48 c1 e8 03 42 80 3c 30 00 0f 85 6c 02 00 00 49 89 6f 58 e9 3a ff ff ff e8 d8 4c 1f 00 e8 e3 76 27 00 fb 4c 89 e8 <48> c1 e8 03 42 80 3c 30 00 0f 84 19 ff ff ff 4c 89 ef e8 88 ab 5a
RSP: 0018:ffff888009a379c0 EFLAGS: 00000206
RAX: ffffffff85f36978 RBX: 0000000000000001 RCX: 0000000000000040
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff81544fcd
RBP: 0000000000000200 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff86439057 R11: 0000000000000001 R12: 0000000000000000
R13: ffffffff85f36978 R14: dffffc0000000000 R15: ffffffff85f36920
console_unlock+0xc2/0x1f0
vprintk_emit+0x437/0x680
_printk+0xbe/0xf0
kauditd_hold_skb+0x205/0x250
kauditd_send_queue+0x233/0x290
kauditd_thread+0x607/0xa80
kthread+0x3c8/0x740
ret_from_fork+0x34b/0x430
ret_from_fork_asm+0x1a/0x30
Allocated by task 280:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
__kasan_slab_alloc+0x59/0x70
kmem_cache_alloc_noprof+0x13c/0x470
copy_process+0x6f3a/0x73e0
kernel_clone+0xea/0x820
__do_sys_clone+0xce/0x120
do_syscall_64+0xbf/0x360
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 4990:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3a/0x60
__kasan_slab_free+0x38/0x50
kmem_cache_free+0x2a1/0x460
mmput+0x305/0x390
do_exit+0x79d/0x2970
do_group_exit+0xd3/0x2a0
get_signal+0x2315/0x2340
arch_do_signal_or_restart+0x80/0x790
exit_to_user_mode_loop+0x8b/0x100
do_syscall_64+0x2f7/0x360
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff8880186047c0
which belongs to the cache mm_struct of size 2456
The buggy address is located 2432 bytes inside of
freed 2456-byte region [ffff8880186047c0, ffff888018605158)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x18600
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88800a11ff81
flags: 0x100000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0100000000000040 ffff888008c4bc80 ffffea0000541200 dead000000000004
raw: 0000000000000000 00000000800c000c 00000000f5000000 ffff88800a11ff81
head: 0100000000000040 ffff888008c4bc80 ffffea0000541200 dead000000000004
head: 0000000000000000 00000000800c000c 00000000f5000000 ffff88800a11ff81
head: 0100000000000003 ffffea0000618001 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff888018605000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888018605080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888018605100: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
^
ffff888018605180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888018605200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
loop3: detected capacity change from 0 to 4
EXT4-fs (loop7): unmounting filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09.
loop7: detected capacity change from 0 to 140
EXT4-fs (loop7): mounted filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09 r/w without journal. Quota mode: none.
ext4 filesystem being mounted at /syzkaller-testdir263789137/syzkaller.Vkr4Gi/34/mnt supports timestamps until 2038-01-19 (0x7fffffff)
loop5: detected capacity change from 0 to 140
EXT4-fs warning (device loop7): ext4_dirblock_csum_verify:375: inode #2: comm syz-executor.7: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs error (device loop7): __ext4_find_entry:1624: inode #2: comm syz-executor.7: checksumming directory block 0
sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=0s
sr 1:0:0:0: [sr0] tag#0 CDB: Read attributes 8c 9f 8c 97 a5 7c 2c cc 65 ef 50 7c
EXT4-fs (loop7): unmounting filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09.
loop3: detected capacity change from 0 to 4
loop5: detected capacity change from 0 to 140
loop3: detected capacity change from 0 to 4
----------------
Code disassembly (best guess):
0: 01 4c 89 e8 add %ecx,-0x18(%rcx,%rcx,4)
4: 48 c1 e8 03 shr $0x3,%rax
8: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1)
d: 0f 85 6c 02 00 00 jne 0x27f
13: 49 89 6f 58 mov %rbp,0x58(%r15)
17: e9 3a ff ff ff jmpq 0xffffff56
1c: e8 d8 4c 1f 00 callq 0x1f4cf9
21: e8 e3 76 27 00 callq 0x277709
26: fb sti
27: 4c 89 e8 mov %r13,%rax
* 2a: 48 c1 e8 03 shr $0x3,%rax <-- trapping instruction
2e: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1)
33: 0f 84 19 ff ff ff je 0xffffff52
39: 4c 89 ef mov %r13,%rdi
3c: e8 .byte 0xe8
3d: 88 .byte 0x88
3e: ab stos %eax,%es:(%rdi)
3f: 5a pop %rdx