possible deadlock in lookup_one_len_unlocked (2)
5 views
Skip to first unread message
syzbot
Aug 12, 2021, 4:17:18 AM8/12/21
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 5c66974a6304 Linux 4.19.202
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14e065fa300000
kernel config: https://syzkaller.appspot.com/x/.config?x=4163258239353ac5
dashboard link: https://syzkaller.appspot.com/bug?extid=91a343ee5926d33c4c0c
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)
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+91a343...@syzkaller.appspotmail.com
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
======================================================
WARNING: possible circular locking dependency detected
4.19.202-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/21542 is trying to acquire lock:
00000000af5edbfb (&ovl_i_mutex_dir_key[depth]#2){++++}, at: inode_lock_shared include/linux/fs.h:758 [inline]
00000000af5edbfb (&ovl_i_mutex_dir_key[depth]#2){++++}, at: lookup_slow fs/namei.c:1688 [inline]
00000000af5edbfb (&ovl_i_mutex_dir_key[depth]#2){++++}, at: lookup_one_len_unlocked+0x111/0x140 fs/namei.c:2573
but task is already holding lock:
0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: inode_lock_shared include/linux/fs.h:758 [inline]
0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: do_last fs/namei.c:3326 [inline]
0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: path_openat+0x17ec/0x2df0 fs/namei.c:3537
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&ovl_i_mutex_dir_key[depth]#3){.+.+}:
inode_lock_shared include/linux/fs.h:758 [inline]
do_last fs/namei.c:3326 [inline]
path_openat+0x17ec/0x2df0 fs/namei.c:3537
do_filp_open+0x18c/0x3f0 fs/namei.c:3567
do_open_execat+0x11d/0x5b0 fs/exec.c:853
__do_execve_file+0x1a8b/0x2360 fs/exec.c:1770
do_execveat_common fs/exec.c:1879 [inline]
do_execve+0x35/0x50 fs/exec.c:1896
__do_sys_execve fs/exec.c:1977 [inline]
__se_sys_execve fs/exec.c:1972 [inline]
__x64_sys_execve+0x7c/0xa0 fs/exec.c:1972
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #3 (&sig->cred_guard_mutex){+.+.}:
lock_trace fs/proc/base.c:402 [inline]
proc_pid_stack+0x160/0x350 fs/proc/base.c:452
proc_single_show+0xeb/0x170 fs/proc/base.c:755
seq_read+0x4e0/0x11c0 fs/seq_file.c:232
__vfs_read+0xf7/0x750 fs/read_write.c:416
vfs_read+0x194/0x3c0 fs/read_write.c:452
ksys_read+0x12b/0x2a0 fs/read_write.c:579
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #2 (&p->lock){+.+.}:
seq_read+0x6b/0x11c0 fs/seq_file.c:164
do_loop_readv_writev fs/read_write.c:701 [inline]
do_loop_readv_writev fs/read_write.c:688 [inline]
do_iter_read+0x471/0x630 fs/read_write.c:925
vfs_readv+0xe5/0x150 fs/read_write.c:987
kernel_readv fs/splice.c:362 [inline]
default_file_splice_read+0x457/0xa00 fs/splice.c:417
do_splice_to+0x10e/0x160 fs/splice.c:881
splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959
do_splice_direct+0x1a7/0x270 fs/splice.c:1068
do_sendfile+0x550/0xc30 fs/read_write.c:1447
__do_sys_sendfile64 fs/read_write.c:1508 [inline]
__se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #1 (sb_writers#3){.+.+}:
sb_start_write include/linux/fs.h:1579 [inline]
mnt_want_write+0x3a/0xb0 fs/namespace.c:360
ovl_do_remove+0xf0/0xdb0 fs/overlayfs/dir.c:843
vfs_rmdir.part.0+0x10f/0x3d0 fs/namei.c:3882
vfs_rmdir fs/namei.c:3868 [inline]
do_rmdir+0x3fd/0x490 fs/namei.c:3943
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #0 (&ovl_i_mutex_dir_key[depth]#2){++++}:
down_read+0x36/0x80 kernel/locking/rwsem.c:24
inode_lock_shared include/linux/fs.h:758 [inline]
lookup_slow fs/namei.c:1688 [inline]
lookup_one_len_unlocked+0x111/0x140 fs/namei.c:2573
ovl_lookup_single+0x60/0x920 fs/overlayfs/namei.c:206
ovl_lookup_layer+0x3bd/0x440 fs/overlayfs/namei.c:292
ovl_lookup+0x729/0x1a00 fs/overlayfs/namei.c:903
lookup_open+0x698/0x1a20 fs/namei.c:3214
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_open_execat+0x11d/0x5b0 fs/exec.c:853
__do_execve_file+0x1a8b/0x2360 fs/exec.c:1770
do_execveat_common fs/exec.c:1879 [inline]
do_execve+0x35/0x50 fs/exec.c:1896
__do_sys_execve fs/exec.c:1977 [inline]
__se_sys_execve fs/exec.c:1972 [inline]
__x64_sys_execve+0x7c/0xa0 fs/exec.c:1972
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
other info that might help us debug this:
Chain exists of:
&ovl_i_mutex_dir_key[depth]#2 --> &sig->cred_guard_mutex --> &ovl_i_mutex_dir_key[depth]#3
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ovl_i_mutex_dir_key[depth]#3);
lock(&sig->cred_guard_mutex);
lock(&ovl_i_mutex_dir_key[depth]#3);
lock(&ovl_i_mutex_dir_key[depth]#2);
*** DEADLOCK ***
2 locks held by syz-executor.1/21542:
#0: 00000000c762181b (&sig->cred_guard_mutex){+.+.}, at: prepare_bprm_creds fs/exec.c:1419 [inline]
#0: 00000000c762181b (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file+0x38c/0x2360 fs/exec.c:1762
#1: 0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: inode_lock_shared include/linux/fs.h:758 [inline]
#1: 0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: do_last fs/namei.c:3326 [inline]
#1: 0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: path_openat+0x17ec/0x2df0 fs/namei.c:3537
stack backtrace:
CPU: 0 PID: 21542 Comm: syz-executor.1 Not tainted 4.19.202-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_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222
check_prev_add kernel/locking/lockdep.c:1866 [inline]
check_prevs_add kernel/locking/lockdep.c:1979 [inline]
validate_chain kernel/locking/lockdep.c:2420 [inline]
__lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416
lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
down_read+0x36/0x80 kernel/locking/rwsem.c:24
inode_lock_shared include/linux/fs.h:758 [inline]
lookup_slow fs/namei.c:1688 [inline]
lookup_one_len_unlocked+0x111/0x140 fs/namei.c:2573
ovl_lookup_single+0x60/0x920 fs/overlayfs/namei.c:206
ovl_lookup_layer+0x3bd/0x440 fs/overlayfs/namei.c:292
ovl_lookup+0x729/0x1a00 fs/overlayfs/namei.c:903
lookup_open+0x698/0x1a20 fs/namei.c:3214
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_open_execat+0x11d/0x5b0 fs/exec.c:853
__do_execve_file+0x1a8b/0x2360 fs/exec.c:1770
do_execveat_common fs/exec.c:1879 [inline]
do_execve+0x35/0x50 fs/exec.c:1896
__do_sys_execve fs/exec.c:1977 [inline]
__se_sys_execve fs/exec.c:1972 [inline]
__x64_sys_execve+0x7c/0xa0 fs/exec.c:1972
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4665e9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f795dee5188 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000020000900 RSI: 0000000020000740 RDI: 0000000020000140
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffe929268af R14: 00007f795dee5300 R15: 0000000000022000
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
netlink: 60 bytes leftover after parsing attributes in process `syz-executor.0'.
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot found the following issue on:
HEAD commit: 5c66974a6304 Linux 4.19.202
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14e065fa300000
kernel config: https://syzkaller.appspot.com/x/.config?x=4163258239353ac5
dashboard link: https://syzkaller.appspot.com/bug?extid=91a343ee5926d33c4c0c
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)
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+91a343...@syzkaller.appspotmail.com
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
======================================================
WARNING: possible circular locking dependency detected
4.19.202-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/21542 is trying to acquire lock:
00000000af5edbfb (&ovl_i_mutex_dir_key[depth]#2){++++}, at: inode_lock_shared include/linux/fs.h:758 [inline]
00000000af5edbfb (&ovl_i_mutex_dir_key[depth]#2){++++}, at: lookup_slow fs/namei.c:1688 [inline]
00000000af5edbfb (&ovl_i_mutex_dir_key[depth]#2){++++}, at: lookup_one_len_unlocked+0x111/0x140 fs/namei.c:2573
but task is already holding lock:
0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: inode_lock_shared include/linux/fs.h:758 [inline]
0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: do_last fs/namei.c:3326 [inline]
0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: path_openat+0x17ec/0x2df0 fs/namei.c:3537
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&ovl_i_mutex_dir_key[depth]#3){.+.+}:
inode_lock_shared include/linux/fs.h:758 [inline]
do_last fs/namei.c:3326 [inline]
path_openat+0x17ec/0x2df0 fs/namei.c:3537
do_filp_open+0x18c/0x3f0 fs/namei.c:3567
do_open_execat+0x11d/0x5b0 fs/exec.c:853
__do_execve_file+0x1a8b/0x2360 fs/exec.c:1770
do_execveat_common fs/exec.c:1879 [inline]
do_execve+0x35/0x50 fs/exec.c:1896
__do_sys_execve fs/exec.c:1977 [inline]
__se_sys_execve fs/exec.c:1972 [inline]
__x64_sys_execve+0x7c/0xa0 fs/exec.c:1972
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #3 (&sig->cred_guard_mutex){+.+.}:
lock_trace fs/proc/base.c:402 [inline]
proc_pid_stack+0x160/0x350 fs/proc/base.c:452
proc_single_show+0xeb/0x170 fs/proc/base.c:755
seq_read+0x4e0/0x11c0 fs/seq_file.c:232
__vfs_read+0xf7/0x750 fs/read_write.c:416
vfs_read+0x194/0x3c0 fs/read_write.c:452
ksys_read+0x12b/0x2a0 fs/read_write.c:579
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #2 (&p->lock){+.+.}:
seq_read+0x6b/0x11c0 fs/seq_file.c:164
do_loop_readv_writev fs/read_write.c:701 [inline]
do_loop_readv_writev fs/read_write.c:688 [inline]
do_iter_read+0x471/0x630 fs/read_write.c:925
vfs_readv+0xe5/0x150 fs/read_write.c:987
kernel_readv fs/splice.c:362 [inline]
default_file_splice_read+0x457/0xa00 fs/splice.c:417
do_splice_to+0x10e/0x160 fs/splice.c:881
splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959
do_splice_direct+0x1a7/0x270 fs/splice.c:1068
do_sendfile+0x550/0xc30 fs/read_write.c:1447
__do_sys_sendfile64 fs/read_write.c:1508 [inline]
__se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #1 (sb_writers#3){.+.+}:
sb_start_write include/linux/fs.h:1579 [inline]
mnt_want_write+0x3a/0xb0 fs/namespace.c:360
ovl_do_remove+0xf0/0xdb0 fs/overlayfs/dir.c:843
vfs_rmdir.part.0+0x10f/0x3d0 fs/namei.c:3882
vfs_rmdir fs/namei.c:3868 [inline]
do_rmdir+0x3fd/0x490 fs/namei.c:3943
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #0 (&ovl_i_mutex_dir_key[depth]#2){++++}:
down_read+0x36/0x80 kernel/locking/rwsem.c:24
inode_lock_shared include/linux/fs.h:758 [inline]
lookup_slow fs/namei.c:1688 [inline]
lookup_one_len_unlocked+0x111/0x140 fs/namei.c:2573
ovl_lookup_single+0x60/0x920 fs/overlayfs/namei.c:206
ovl_lookup_layer+0x3bd/0x440 fs/overlayfs/namei.c:292
ovl_lookup+0x729/0x1a00 fs/overlayfs/namei.c:903
lookup_open+0x698/0x1a20 fs/namei.c:3214
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_open_execat+0x11d/0x5b0 fs/exec.c:853
__do_execve_file+0x1a8b/0x2360 fs/exec.c:1770
do_execveat_common fs/exec.c:1879 [inline]
do_execve+0x35/0x50 fs/exec.c:1896
__do_sys_execve fs/exec.c:1977 [inline]
__se_sys_execve fs/exec.c:1972 [inline]
__x64_sys_execve+0x7c/0xa0 fs/exec.c:1972
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
other info that might help us debug this:
Chain exists of:
&ovl_i_mutex_dir_key[depth]#2 --> &sig->cred_guard_mutex --> &ovl_i_mutex_dir_key[depth]#3
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ovl_i_mutex_dir_key[depth]#3);
lock(&sig->cred_guard_mutex);
lock(&ovl_i_mutex_dir_key[depth]#3);
lock(&ovl_i_mutex_dir_key[depth]#2);
*** DEADLOCK ***
2 locks held by syz-executor.1/21542:
#0: 00000000c762181b (&sig->cred_guard_mutex){+.+.}, at: prepare_bprm_creds fs/exec.c:1419 [inline]
#0: 00000000c762181b (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file+0x38c/0x2360 fs/exec.c:1762
#1: 0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: inode_lock_shared include/linux/fs.h:758 [inline]
#1: 0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: do_last fs/namei.c:3326 [inline]
#1: 0000000000fade74 (&ovl_i_mutex_dir_key[depth]#3){.+.+}, at: path_openat+0x17ec/0x2df0 fs/namei.c:3537
stack backtrace:
CPU: 0 PID: 21542 Comm: syz-executor.1 Not tainted 4.19.202-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_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222
check_prev_add kernel/locking/lockdep.c:1866 [inline]
check_prevs_add kernel/locking/lockdep.c:1979 [inline]
validate_chain kernel/locking/lockdep.c:2420 [inline]
__lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416
lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
down_read+0x36/0x80 kernel/locking/rwsem.c:24
inode_lock_shared include/linux/fs.h:758 [inline]
lookup_slow fs/namei.c:1688 [inline]
lookup_one_len_unlocked+0x111/0x140 fs/namei.c:2573
ovl_lookup_single+0x60/0x920 fs/overlayfs/namei.c:206
ovl_lookup_layer+0x3bd/0x440 fs/overlayfs/namei.c:292
ovl_lookup+0x729/0x1a00 fs/overlayfs/namei.c:903
lookup_open+0x698/0x1a20 fs/namei.c:3214
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_open_execat+0x11d/0x5b0 fs/exec.c:853
__do_execve_file+0x1a8b/0x2360 fs/exec.c:1770
do_execveat_common fs/exec.c:1879 [inline]
do_execve+0x35/0x50 fs/exec.c:1896
__do_sys_execve fs/exec.c:1977 [inline]
__se_sys_execve fs/exec.c:1972 [inline]
__x64_sys_execve+0x7c/0xa0 fs/exec.c:1972
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4665e9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f795dee5188 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000020000900 RSI: 0000000020000740 RDI: 0000000020000140
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffe929268af R14: 00007f795dee5300 R15: 0000000000022000
overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off.
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
netlink: 60 bytes leftover after parsing attributes in process `syz-executor.0'.
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot
Dec 30, 2021, 3:51:13 PM12/30/21
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
Crashes did not happen for a while, no reproducer and no activity.
Reply all
Reply to author
Forward
0 new messages