==================================================================
BUG: KASAN: use-after-free in tw_timer_handler+0x8f/0xf0 include/net/net_namespace.h:-1
Read of size 8 at addr ffff88811683d198 by task syz.4.8724/30879
CPU: 1 PID: 30879 Comm: syz.4.8724 Tainted: G W 5.15.185-syzkaller-00339-ge678c93d43cc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
__dump_stack+0x21/0x30 lib/dump_stack.c:88
dump_stack_lvl+0xee/0x150 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
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
tw_timer_handler+0x8f/0xf0 include/net/net_namespace.h:-1
call_timer_fn+0x38/0x290 kernel/time/timer.c:1457
expire_timers kernel/time/timer.c:1502 [inline]
__run_timers+0x639/0x9a0 kernel/time/timer.c:1773
run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1786
handle_softirqs+0x250/0x560 kernel/softirq.c:583
__do_softirq kernel/softirq.c:621 [inline]
invoke_softirq kernel/softirq.c:443 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:670
irq_exit_rcu+0x9/0x10 kernel/softirq.c:682
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:schedule_timeout+0xa6/0x2e0 kernel/time/timer.c:1929
Code: fc ba 38 00 00 00 4c 89 f7 31 f6 e8 44 d7 01 fd 4c 89 ff 48 89 de e8 89 67 c3 fc 4c 39 fb 75 0f e8 3f 63 c3 fc e8 5a 03 ff ff d2 00 00 00 31 ff 48 89 de e8 6b 67 c3 fc 48 85 db 0f 88 fe 00
RSP: 0018:ffffc9000186f5a0 EFLAGS: 00000246
RAX: 0000000000400140 RBX: 7fffffffffffffff RCX: ffffffff84a447e5
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888118a12780
RBP: ffffc9000186f670 R08: dffffc0000000000 R09: ffffed10231424f1
R10: ffffed10231424f1 R11: 1ffff110231424f0 R12: dffffc0000000000
R13: 1ffff9200030deb4 R14: ffffc9000186f5c0 R15: 7fffffffffffffff
unix_wait_for_peer+0x1e5/0x2e0 net/unix/af_unix.c:1308
unix_dgram_sendmsg+0x1068/0x1880 net/unix/af_unix.c:1906
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
__sys_sendmmsg+0x278/0x480 net/socket.c:2576
__do_sys_sendmmsg net/socket.c:2605 [inline]
__se_sys_sendmmsg net/socket.c:2602 [inline]
__x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2602
x64_sys_call+0x6c6/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:308
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: 0033:0x7f2040527929
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:00007f203eb90038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f204074efa0 RCX: 00007f2040527929
RDX: 0000000000000651 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007f20405a9b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f204074efa0 R15: 00007ffeec8d5a58
Allocated by task 29451:
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:3240 [inline]
slab_alloc mm/slub.c:3250 [inline]
kmem_cache_alloc+0xf7/0x260 mm/slub.c:3255
kmem_cache_zalloc include/linux/slab.h:737 [inline]
net_alloc net/core/net_namespace.c:408 [inline]
copy_net_ns+0x145/0x5c0 net/core/net_namespace.c:463
create_new_namespaces+0x3a2/0x660 kernel/nsproxy.c:110
unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:226
ksys_unshare+0x4ac/0x7b0 kernel/fork.c:3242
__do_sys_unshare kernel/fork.c:3316 [inline]
__se_sys_unshare kernel/fork.c:3314 [inline]
__x64_sys_unshare+0x38/0x40 kernel/fork.c:3314
x64_sys_call+0x442/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:273
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 27491:
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:1723 [inline]
slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1749
slab_free mm/slub.c:3521 [inline]
kmem_cache_free+0x100/0x320 mm/slub.c:3539
net_free net/core/net_namespace.c:437 [inline]
cleanup_net+0xa2d/0xad0 net/core/net_namespace.c:620
process_one_work+0x6be/0xba0 kernel/workqueue.c:2325
worker_thread+0xa59/0x1200 kernel/workqueue.c:2472
kthread+0x411/0x500 kernel/kthread.c:337
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
The buggy address belongs to the object at ffff88811683d000
which belongs to the cache net_namespace of size 3968
The buggy address is located 408 bytes inside of
3968-byte region [ffff88811683d000, ffff88811683df80)
The buggy address belongs to the page:
page:ffffea00045a0e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88811683e000 pfn:0x116838
head:ffffea00045a0e00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 0000000000000000 0000000100000001 ffff8881001c5080
raw: ffff88811683e000 0000000080080004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 21693, ts 1496296853960, free_ts 1496259054896
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+0x2cc5/0x2d50 mm/page_alloc.c:4485
__alloc_pages+0x18f/0x440 mm/page_alloc.c:5789
alloc_slab_page mm/slub.c:-1 [inline]
allocate_slab mm/slub.c:1932 [inline]
new_slab+0xa1/0x4d0 mm/slub.c:1995
___slab_alloc+0x381/0x810 mm/slub.c:3028
__slab_alloc+0x49/0x90 mm/slub.c:3115
slab_alloc_node mm/slub.c:3206 [inline]
slab_alloc mm/slub.c:3250 [inline]
kmem_cache_alloc+0x138/0x260 mm/slub.c:3255
kmem_cache_zalloc include/linux/slab.h:737 [inline]
net_alloc net/core/net_namespace.c:408 [inline]
copy_net_ns+0x145/0x5c0 net/core/net_namespace.c:463
create_new_namespaces+0x3a2/0x660 kernel/nsproxy.c:110
unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:226
ksys_unshare+0x4ac/0x7b0 kernel/fork.c:3242
__do_sys_unshare kernel/fork.c:3316 [inline]
__se_sys_unshare kernel/fork.c:3314 [inline]
__x64_sys_unshare+0x38/0x40 kernel/fork.c:3314
x64_sys_call+0x442/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:273
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+0xa2/0x550 mm/page_alloc.c:3616
free_the_page mm/page_alloc.c:805 [inline]
__free_pages+0x6c/0x100 mm/page_alloc.c:5865
__free_slab+0xe8/0x1e0 mm/slub.c:2020
free_slab mm/slub.c:2035 [inline]
discard_slab mm/slub.c:2041 [inline]
__unfreeze_partials+0x160/0x190 mm/slub.c:2527
put_cpu_partial+0xc6/0x120 mm/slub.c:2607
__slab_free+0x1d4/0x290 mm/slub.c:3390
do_slab_free mm/slub.c:3509 [inline]
___cache_free+0x104/0x120 mm/slub.c:3530
qlink_free+0x4d/0x90 mm/kasan/quarantine.c:157
qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:283
____kasan_kmalloc mm/kasan/common.c:478 [inline]
__kasan_kmalloc+0x2f/0x110 mm/kasan/common.c:521
kasan_kmalloc include/linux/kasan.h:227 [inline]
kmem_cache_alloc_trace+0x119/0x270 mm/slub.c:3269
kmalloc include/linux/slab.h:616 [inline]
kzalloc include/linux/slab.h:747 [inline]
kobject_uevent_env+0x272/0x700 lib/kobject_uevent.c:539
kobject_uevent+0x1d/0x30 lib/kobject_uevent.c:657
loop_configure+0x138b/0x1730 drivers/block/loop.c:1324
Memory state around the buggy address:
ffff88811683d080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811683d100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811683d180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811683d200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811683d280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: fc cld
1: ba 38 00 00 00 mov $0x38,%edx
6: 4c 89 f7 mov %r14,%rdi
9: 31 f6 xor %esi,%esi
b: e8 44 d7 01 fd call 0xfd01d754
10: 4c 89 ff mov %r15,%rdi
13: 48 89 de mov %rbx,%rsi
16: e8 89 67 c3 fc call 0xfcc367a4
1b: 4c 39 fb cmp %r15,%rbx
1e: 75 0f jne 0x2f
20: e8 3f 63 c3 fc call 0xfcc36364
25: e8 5a 03 ff ff call 0xffff0384
* 2a: e9 d2 00 00 00 jmp 0x101 <-- trapping instruction
2f: 31 ff xor %edi,%edi
31: 48 89 de mov %rbx,%rsi
34: e8 6b 67 c3 fc call 0xfcc367a4
39: 48 85 db test %rbx,%rbx
3c: 0f .byte 0xf
3d: 88 fe mov %bh,%dh