==================================================================
BUG: KASAN: slab-use-after-free in flush_tlb_func+0x24d/0x560
Write of size 8 at addr ffff888013bcbcc0 by task syz-executor.7/4940
CPU: 0 UID: 0 PID: 4940 Comm: syz-executor.7 Not tainted 6.16.0-rc4-next-20250630 #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+0x5f/0xc0
asm_sysvec_call_function_single+0x1a/0x20
RIP: 0010:handle_softirqs+0x174/0x770
Code: c8 83 83 3c 0a 00 00 01 c7 44 24 20 0a 00 00 00 48 89 44 24 18 65 66 c7 05 cf 84 47 06 00 00 e8 22 65 40 00 fb bb ff ff ff ff <48> c7 c5 c0 c0 a0 85 41 0f bc de 83 c3 01 0f 85 9b 00 00 00 e9 8d
RSP: 0018:ffff88806ce08f78 EFLAGS: 00000206
RAX: 00000000000000cc RBX: 00000000ffffffff RCX: 0000000000000004
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff813b5b6e
RBP: ffff888016d1fb18 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff86438657 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000382 R15: 0000000000000000
__irq_exit_rcu+0xc4/0x100
irq_exit_rcu+0x9/0x20
sysvec_apic_timer_interrupt+0x70/0x80
asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:dump_stack_lvl+0x115/0x120
Code: fc ff ff 4c 89 e2 31 f6 31 ff e8 e6 40 7b fc e8 e1 f7 a4 fc 48 89 ee 31 ff e8 d7 95 c4 fc e8 72 9a c4 fc e8 7d c4 cc fc fb 5b <5d> 41 5c e9 63 9a c4 fc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffff888016d1fbc8 EFLAGS: 00000206
RAX: 00000000000000c9 RBX: ffffffff85e964a0 RCX: 0000000000000040
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff84aefc13
RBP: 0000000000000200 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff86438657 R11: 0000000000000001 R12: ffffffff8530f500
R13: ffffffff85e964b0 R14: 0000000000000000 R15: 0000000000000000
should_fail_ex+0x4d7/0x5e0
_copy_to_user+0x32/0xd0
simple_read_from_buffer+0xe0/0x180
proc_fail_nth_read+0x189/0x270
vfs_read+0x1eb/0xbe0
ksys_read+0x121/0x240
do_syscall_64+0xbf/0x360
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5b4a39569c
Code: ec 28 48 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 fc ff ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 48 89 44 24 08 e8 2f fd ff ff 48
RSP: 002b:00007f5b47958170 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f5b4a39569c
RDX: 000000000000000f RSI: 00007f5b479581e0 RDI: 0000000000000003
RBP: 00007f5b479581d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000040 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffe10f92f6f R14: 00007f5b47958300 R15: 0000000000022000
syz-executor.4: attempt to access beyond end of device
loop4: rw=0, sector=0, nr_sectors = 1 limit=0
Allocated by task 282:
kasan_save_stack+0x24/0x50
FAT-fs (loop4): unable to read boot sector
kasan_save_track+0x14/0x30
syz-executor.3: attempt to access beyond end of device
loop3: rw=0, sector=0, nr_sectors = 1 limit=0
__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 4934:
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 ffff888013bcb340
which belongs to the cache mm_struct of size 2456
The buggy address is located 2432 bytes inside of
freed 2456-byte region [ffff888013bcb340, ffff888013bcbcd8)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x13bc8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88800bd98481
flags: 0x100000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0100000000000040 ffff888008c4bc80 dead000000000100 dead000000000122
raw: 0000000000000000 00000000800c000c 00000000f5000000 ffff88800bd98481
head: 0100000000000040 ffff888008c4bc80 dead000000000100 dead000000000122
head: 0000000000000000 00000000800c000c 00000000f5000000 ffff88800bd98481
head: 0100000000000003 ffffea00004ef201 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff888013bcbb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888013bcbc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888013bcbc80: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
^
ffff888013bcbd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888013bcbd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
FAT-fs (loop3): unable to read boot sector
syz-executor.4: attempt to access beyond end of device
loop4: rw=0, sector=0, nr_sectors = 1 limit=0
FAT-fs (loop4): unable to read boot sector
syz-executor.3: attempt to access beyond end of device
loop3: rw=0, sector=0, nr_sectors = 1 limit=0
loop4: detected capacity change from 0 to 1
FAT-fs (loop3): unable to read boot sector
FAT-fs (loop4): bogus number of reserved sectors
FAT-fs (loop4): Can't find a valid FAT filesystem
loop3: detected capacity change from 0 to 1
FAT-fs (loop3): invalid media value (0x00)
FAT-fs (loop3): Can't find a valid FAT filesystem
----------------
Code disassembly (best guess):
0: c8 83 83 3c enterq $0x8383,$0x3c
4: 0a 00 or (%rax),%al
6: 00 01 add %al,(%rcx)
8: c7 44 24 20 0a 00 00 movl $0xa,0x20(%rsp)
f: 00
10: 48 89 44 24 18 mov %rax,0x18(%rsp)
15: 65 66 c7 05 cf 84 47 movw $0x0,%gs:0x64784cf(%rip) # 0x64784ee
1c: 06 00 00
1f: e8 22 65 40 00 callq 0x406546
24: fb sti
25: bb ff ff ff ff mov $0xffffffff,%ebx
* 2a: 48 c7 c5 c0 c0 a0 85 mov $0xffffffff85a0c0c0,%rbp <-- trapping instruction
31: 41 0f bc de bsf %r14d,%ebx
35: 83 c3 01 add $0x1,%ebx
38: 0f 85 9b 00 00 00 jne 0xd9
3e: e9 .byte 0xe9
3f: 8d .byte 0x8d