syzbot
KASAN: use-after-free Read in chrdev_open
Status:
upstream: reported C repro on 2021/02/11 04:55
Reported-by: syzbot+7c5ec771fa8a51b6c096@syzkaller.appspotmail.com
First crash: 1992d, last: 1427d
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Fix bisection attempts (8)
Sample crash report:
==================================================================
BUG: KASAN: use-after-free in __list_add_valid+0x81/0xa0 lib/list_debug.c:23
Read of size 8 at addr ffff88808dfca3c0 by task syz-executor411/8086
CPU: 1 PID: 8086 Comm: syz-executor411 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
kasan_report mm/kasan/report.c:412 [inline]
__asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
__list_add_valid+0x81/0xa0 lib/list_debug.c:23
__list_add include/linux/list.h:60 [inline]
list_add include/linux/list.h:79 [inline]
chrdev_open+0x4b9/0x770 fs/char_dev.c:405
do_dentry_open+0x4aa/0x1160 fs/open.c:796
do_last fs/namei.c:3421 [inline]
path_openat+0x793/0x2df0 fs/namei.c:3537
do_filp_open+0x18c/0x3f0 fs/namei.c:3567
do_sys_open+0x3b3/0x520 fs/open.c:1085
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fab1f484b29
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 90 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:00007fab1f4142f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007fab1f5124d0 RCX: 00007fab1f484b29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000080
RBP: 00007fab1f4df154 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fab1f4db148
R13: 00007fab1f4dd150 R14: 2f30656c69662f2e R15: 00007fab1f5124d8
Allocated by task 8079:
kmem_cache_alloc+0x122/0x370 mm/slab.c:3559
fuse_alloc_inode+0x1d/0x3f0 fs/fuse/inode.c:87
alloc_inode+0x5d/0x180 fs/inode.c:211
iget5_locked fs/inode.c:1131 [inline]
iget5_locked+0x57/0xd0 fs/inode.c:1124
fuse_iget+0x1a6/0x800 fs/fuse/inode.c:307
fuse_lookup_name+0x413/0x5c0 fs/fuse/dir.c:341
fuse_lookup+0xdf/0x410 fs/fuse/dir.c:368
fuse_atomic_open+0x20a/0x330 fs/fuse/dir.c:508
atomic_open fs/namei.c:3073 [inline]
lookup_open+0x1023/0x1a20 fs/namei.c:3205
do_last fs/namei.c:3327 [inline]
path_openat+0x1804/0x2df0 fs/namei.c:3537
do_filp_open+0x18c/0x3f0 fs/namei.c:3567
do_sys_open+0x3b3/0x520 fs/open.c:1085
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 0:
__cache_free mm/slab.c:3503 [inline]
kmem_cache_free+0x7f/0x260 mm/slab.c:3765
__rcu_reclaim kernel/rcu/rcu.h:236 [inline]
rcu_do_batch kernel/rcu/tree.c:2584 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2897 [inline]
__rcu_process_callbacks kernel/rcu/tree.c:2864 [inline]
rcu_process_callbacks+0x8ff/0x18b0 kernel/rcu/tree.c:2881
__do_softirq+0x265/0x980 kernel/softirq.c:292
The buggy address belongs to the object at ffff88808dfca040
which belongs to the cache fuse_inode of size 1264
The buggy address is located 896 bytes inside of
1264-byte region [ffff88808dfca040, ffff88808dfca530)
The buggy address belongs to the page:
page:ffffea000237f280 count:1 mapcount:0 mapping:ffff8880b0f81780 index:0xffff88808dfcaffe
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffff8880b0f88a48 ffffea000237e508 ffff8880b0f81780
raw: ffff88808dfcaffe ffff88808dfca040 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88808dfca280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88808dfca300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808dfca380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88808dfca400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88808dfca480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
* Struck through repros no longer work on HEAD.