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

syzbot
2022-01-11T11:03:20Z

Hello,

syzbot found the following issue on:

HEAD commit: 3770333b3f8c Add linux-next specific files for 20220106
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=171aa4e3b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=f9eb40d9f910b474
dashboard link: https://syzkaller.appspot.com/bug?extid=4f789823c1abc5accf13
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12b08f53b00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4f789823c1abc5accf13@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in rcu_seq_snap kernel/rcu/rcu.h:91 [inline]
BUG: KASAN: use-after-free in srcu_invoke_callbacks+0x391/0x3c0 kernel/rcu/srcutree.c:1283
Read of size 8 at addr ffff8880189b6968 by task kworker/0:1/7

CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.16.0-rc8-next-20220106-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: rcu_gp srcu_invoke_callbacks
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+0xa5/0x3ed mm/kasan/report.c:255
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
rcu_seq_snap kernel/rcu/rcu.h:91 [inline]
srcu_invoke_callbacks+0x391/0x3c0 kernel/rcu/srcutree.c:1283
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
</TASK>

Allocated by task 19830:
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_slab_alloc+0x90/0xc0 mm/kasan/common.c:469
kasan_slab_alloc include/linux/kasan.h:260 [inline]
slab_post_alloc_hook mm/slab.h:738 [inline]
slab_alloc_node mm/slub.c:3230 [inline]
kmem_cache_alloc_node+0x255/0x3e0 mm/slub.c:3266
blk_alloc_queue+0x5ad/0x870 block/blk-core.c:446
blk_mq_init_queue_data block/blk-mq.c:3878 [inline]
__blk_mq_alloc_disk+0x8c/0x1c0 block/blk-mq.c:3902
nbd_dev_add+0x3b2/0xcd0 drivers/block/nbd.c:1765
nbd_genl_connect+0x11f3/0x1930 drivers/block/nbd.c:1948
genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1343
netlink_sendmsg+0x904/0xdf0 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:705 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:725
____sys_sendmsg+0x6e8/0x810 net/socket.c:2410
___sys_sendmsg+0xf3/0x170 net/socket.c:2464
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2493
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 13:
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+0x166/0x1a0 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:236 [inline]
slab_free_hook mm/slub.c:1728 [inline]
slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754
slab_free mm/slub.c:3509 [inline]
kmem_cache_free+0xdb/0x3b0 mm/slub.c:3526
rcu_do_batch kernel/rcu/tree.c:2536 [inline]
rcu_core+0x7b8/0x1540 kernel/rcu/tree.c:2787
__do_softirq+0x29b/0x9c2 kernel/softirq.c:558

Last potentially related work creation:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
__kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348
call_rcu+0x99/0x730 kernel/rcu/tree.c:3072
kobject_cleanup lib/kobject.c:705 [inline]
kobject_release lib/kobject.c:736 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1c8/0x540 lib/kobject.c:753
disk_release+0x19a/0x260 block/genhd.c:1116
device_release+0x9f/0x240 drivers/base/core.c:2229
kobject_cleanup lib/kobject.c:705 [inline]
kobject_release lib/kobject.c:736 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1c8/0x540 lib/kobject.c:753
put_device+0x1b/0x30 drivers/base/core.c:3512
put_disk block/genhd.c:1368 [inline]
blk_cleanup_disk+0x6b/0x80 block/genhd.c:1384
nbd_dev_remove+0x44/0xf0 drivers/block/nbd.c:253
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

Second to last potentially related work creation:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
__kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348
insert_work+0x48/0x370 kernel/workqueue.c:1368
__queue_work+0x5ca/0xf30 kernel/workqueue.c:1534
__queue_delayed_work+0x1c8/0x270 kernel/workqueue.c:1682
queue_delayed_work_on+0x105/0x120 kernel/workqueue.c:1718
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 ffff8880189b5c70
which belongs to the cache request_queue_srcu of size 3816
The buggy address is located 3320 bytes inside of
3816-byte region [ffff8880189b5c70, ffff8880189b6b58)
The buggy address belongs to the page:
page:ffffea0000626c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x189b0
head:ffffea0000626c00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888012787140
raw: 0000000000000000 0000000080080008 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 14963, ts 196854875504, free_ts 196839673140
prep_new_page mm/page_alloc.c:2434 [inline]
get_page_from_freelist+0xa72/0x2f40 mm/page_alloc.c:4165
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5381
alloc_pages+0x1aa/0x310 mm/mempolicy.c:2271
alloc_slab_page mm/slub.c:1799 [inline]
allocate_slab mm/slub.c:1944 [inline]
new_slab+0x28d/0x380 mm/slub.c:2004
___slab_alloc+0x6be/0xd60 mm/slub.c:3018
__slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105
slab_alloc_node mm/slub.c:3196 [inline]
kmem_cache_alloc_node+0x122/0x3e0 mm/slub.c:3266
blk_alloc_queue+0x5ad/0x870 block/blk-core.c:446
blk_mq_init_queue_data block/blk-mq.c:3878 [inline]
__blk_mq_alloc_disk+0x8c/0x1c0 block/blk-mq.c:3902
nbd_dev_add+0x3b2/0xcd0 drivers/block/nbd.c:1765
nbd_genl_connect+0x11f3/0x1930 drivers/block/nbd.c:1948
genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1343
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+0x414/0xb60 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
__unfreeze_partials+0x17c/0x1a0 mm/slub.c:2536
qlink_free mm/kasan/quarantine.c:157 [inline]
qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
kasan_slab_alloc include/linux/kasan.h:260 [inline]
slab_post_alloc_hook mm/slab.h:738 [inline]
slab_alloc_node mm/slub.c:3230 [inline]
slab_alloc mm/slub.c:3238 [inline]
__kmalloc+0x1e7/0x340 mm/slub.c:4420
kmalloc include/linux/slab.h:586 [inline]
tomoyo_realpath_from_path+0xc3/0x620 security/tomoyo/realpath.c:254
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x21b/0x400 security/tomoyo/file.c:822
security_inode_getattr+0xcf/0x140 security/security.c:1326
vfs_getattr fs/stat.c:157 [inline]
vfs_statx+0x164/0x390 fs/stat.c:225
vfs_fstatat fs/stat.c:243 [inline]
__do_sys_newfstatat+0x96/0x120 fs/stat.c:412
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

Memory state around the buggy address:
ffff8880189b6800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880189b6880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880189b6900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880189b6980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880189b6a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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