[syzbot] KASAN: use-after-free Read in io_poll_remove_entries

syzbot
2022-03-22T08:52:26Z

Hello,

syzbot found the following issue on:

HEAD commit: 8565d64430f8 Merge tag 'bounds-fixes-v5.18-rc1' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15406ddb700000
kernel config: https://syzkaller.appspot.com/x/.config?x=89040bbe61f60a52
dashboard link: https://syzkaller.appspot.com/bug?extid=cd301bb6523ea8cc8ca2
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cd301bb6523ea8cc8ca2@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in __list_del_entry_valid+0xe0/0xf0 lib/list_debug.c:51
Read of size 8 at addr ffff8880700bed30 by task syz-executor.2/5247

CPU: 0 PID: 5247 Comm: syz-executor.2 Tainted: G W 5.17.0-syzkaller-01402-g8565d64430f8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
__list_del_entry_valid+0xe0/0xf0 lib/list_debug.c:51
__list_del_entry include/linux/list.h:134 [inline]
list_del_init include/linux/list.h:206 [inline]
io_poll_remove_entry fs/io_uring.c:5863 [inline]
io_poll_remove_entries.part.0+0x167/0x7e0 fs/io_uring.c:5895
io_poll_remove_entries fs/io_uring.c:5875 [inline]
io_apoll_task_func+0xba/0x230 fs/io_uring.c:5995
handle_tw_list fs/io_uring.c:2480 [inline]
tctx_task_work+0x1a2/0x1380 fs/io_uring.c:2514
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
tracehook_notify_signal include/linux/tracehook.h:213 [inline]
handle_signal_work kernel/entry/common.c:146 [inline]
exit_to_user_mode_loop kernel/entry/common.c:186 [inline]
exit_to_user_mode_prepare+0x256/0x290 kernel/entry/common.c:221
__syscall_exit_to_user_mode_work kernel/entry/common.c:303 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:314
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f2400e65049
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f23ff7da168 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: 0000000000001261 RBX: 00007f2400f77f60 RCX: 00007f2400e65049
RDX: 0000000000000000 RSI: 0000000000001261 RDI: 0000000000000004
RBP: 00007f2400ebf08d R08: 0000000000000000 R09: 0000000030000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd5a0e325f R14: 00007f23ff7da300 R15: 0000000000022000
</TASK>

Allocated by task 5243:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:436 [inline]
____kasan_kmalloc mm/kasan/common.c:515 [inline]
____kasan_kmalloc mm/kasan/common.c:474 [inline]
__kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524
kasan_kmalloc include/linux/kasan.h:249 [inline]
kmem_cache_alloc_trace+0x1ea/0x4a0 mm/slab.c:3567
kmalloc include/linux/slab.h:581 [inline]
io_arm_poll_handler+0x39d/0x940 fs/io_uring.c:6248
io_queue_sqe_arm_apoll+0x6d/0x430 fs/io_uring.c:7499
__io_queue_sqe fs/io_uring.c:7541 [inline]
io_queue_sqe fs/io_uring.c:7568 [inline]
io_submit_sqe fs/io_uring.c:7776 [inline]
io_submit_sqes+0x7dda/0x9310 fs/io_uring.c:7882
__do_sys_io_uring_enter+0x9f1/0x1520 fs/io_uring.c:10924
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 5258:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free+0xff/0x140 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:215 [inline]
__cache_free mm/slab.c:3437 [inline]
kfree+0xf8/0x2b0 mm/slab.c:3794
io_clean_op+0x20a/0xd90 fs/io_uring.c:7137
io_dismantle_req fs/io_uring.c:2270 [inline]
__io_free_req+0xc8/0x3c5 fs/io_uring.c:2280
io_put_req_find_next fs/io_uring.c:2717 [inline]
io_wq_free_work.cold+0x10/0x69 fs/io_uring.c:7301
io_worker_handle_work+0xb3e/0x1b30 fs/io-wq.c:598
io_wqe_worker+0x606/0xd40 fs/io-wq.c:642
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Last potentially related work creation:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
__kasan_record_aux_stack+0x7e/0x90 mm/kasan/generic.c:348
kvfree_call_rcu+0x74/0x990 kernel/rcu/tree.c:3595
cfg80211_update_known_bss+0x833/0xa60 net/wireless/scan.c:1661
cfg80211_bss_update+0xef/0x2070 net/wireless/scan.c:1708
cfg80211_inform_single_bss_frame_data+0x72b/0xf30 net/wireless/scan.c:2464
cfg80211_inform_bss_frame_data+0xa7/0xb50 net/wireless/scan.c:2497
ieee80211_bss_info_update+0x35b/0xb00 net/mac80211/scan.c:190
ieee80211_rx_bss_info net/mac80211/ibss.c:1119 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1610 [inline]
ieee80211_ibss_rx_queued_mgmt+0x19cf/0x3150 net/mac80211/ibss.c:1639
ieee80211_iface_process_skb net/mac80211/iface.c:1527 [inline]
ieee80211_iface_work+0xa69/0xd00 net/mac80211/iface.c:1581
process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
worker_thread+0x657/0x1110 kernel/workqueue.c:2454
kthread+0x2e9/0x3a0 kernel/kthread.c:377
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff8880700bed00
which belongs to the cache kmalloc-96 of size 96
The buggy address is located 48 bytes inside of
96-byte region [ffff8880700bed00, ffff8880700bed60)
The buggy address belongs to the page:
page:ffffea0001c02f80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x700be
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0000736b88 ffffea0001eb7448 ffff888010c40300
raw: 0000000000000000 ffff8880700be000 0000000100000020 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x342220(__GFP_HIGH|__GFP_ATOMIC|__GFP_NOWARN|__GFP_COMP|__GFP_HARDWALL|__GFP_THISNODE), pid 0, ts 118360599722, free_ts 118282284710
prep_new_page mm/page_alloc.c:2434 [inline]
get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389
__alloc_pages_node include/linux/gfp.h:572 [inline]
kmem_getpages mm/slab.c:1378 [inline]
cache_grow_begin+0x75/0x390 mm/slab.c:2584
cache_alloc_refill+0x27f/0x380 mm/slab.c:2957
____cache_alloc mm/slab.c:3040 [inline]
____cache_alloc mm/slab.c:3023 [inline]
__do_cache_alloc mm/slab.c:3267 [inline]
slab_alloc mm/slab.c:3308 [inline]
kmem_cache_alloc_trace+0x380/0x4a0 mm/slab.c:3565
kmalloc include/linux/slab.h:581 [inline]
dst_cow_metrics_generic+0x48/0x1e0 net/core/dst.c:199
dst_metrics_write_ptr include/net/dst.h:119 [inline]
dst_metric_set include/net/dst.h:180 [inline]
icmp6_dst_alloc+0x4fb/0x6c0 net/ipv6/route.c:3284
ndisc_send_skb+0x1146/0x17f0 net/ipv6/ndisc.c:488
ndisc_send_rs+0x12e/0x6f0 net/ipv6/ndisc.c:702
addrconf_rs_timer+0x3f2/0x820 net/ipv6/addrconf.c:3915
call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
expire_timers kernel/time/timer.c:1466 [inline]
__run_timers.part.0+0x67c/0xa30 kernel/time/timer.c:1734
__run_timers kernel/time/timer.c:1715 [inline]
run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747
__do_softirq+0x29b/0x9c2 kernel/softirq.c:558
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1352 [inline]
free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404
free_unref_page_prepare mm/page_alloc.c:3325 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3404
slab_destroy mm/slab.c:1630 [inline]
slabs_destroy+0x89/0xc0 mm/slab.c:1650
cache_flusharray mm/slab.c:3410 [inline]
___cache_free+0x303/0x600 mm/slab.c:3472
qlink_free mm/kasan/quarantine.c:157 [inline]
qlist_free_all+0x50/0x1a0 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x97/0xb0 mm/kasan/common.c:446
kasan_slab_alloc include/linux/kasan.h:239 [inline]
slab_post_alloc_hook mm/slab.h:732 [inline]
slab_alloc_node mm/slab.c:3253 [inline]
kmem_cache_alloc_node+0x2ea/0x590 mm/slab.c:3591
__alloc_skb+0x215/0x340 net/core/skbuff.c:414
alloc_skb include/linux/skbuff.h:1158 [inline]
alloc_skb_with_frags+0x93/0x620 net/core/skbuff.c:5956
sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2586
mld_newpack.isra.0+0x1be/0x750 net/ipv6/mcast.c:1746
add_grhead+0x283/0x360 net/ipv6/mcast.c:1849
add_grec+0x106a/0x1530 net/ipv6/mcast.c:1987
mld_send_initial_cr.part.0+0xf6/0x230 net/ipv6/mcast.c:2234
mld_send_initial_cr net/ipv6/mcast.c:1232 [inline]
mld_dad_work+0x1d3/0x690 net/ipv6/mcast.c:2260

Memory state around the buggy address:
ffff8880700bec00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff8880700bec80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff8880700bed00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
^
ffff8880700bed80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff8880700bee00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================

---
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