====================================================== WARNING: possible circular locking dependency detected 4.19.154-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.2/22598 is trying to acquire lock: 000000007d1ec2c8 (&sig->cred_guard_mutex){+.+.}, at: do_io_accounting fs/proc/base.c:2737 [inline] 000000007d1ec2c8 (&sig->cred_guard_mutex){+.+.}, at: proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2780 but task is already holding lock: 00000000cb7d0a15 (&p->lock){+.+.}, at: seq_read+0x6b/0x1160 fs/seq_file.c:161 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: seq_read+0x6b/0x1160 fs/seq_file.c:161 proc_reg_read+0x1bd/0x2d0 fs/proc/inode.c:231 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 -> #2 (sb_writers#3){.+.+}: sb_start_write include/linux/fs.h:1579 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:360 ovl_setattr+0xdd/0x920 fs/overlayfs/inode.c:30 notify_change+0x70b/0xfc0 fs/attr.c:334 do_truncate+0x134/0x1f0 fs/open.c:63 handle_truncate fs/namei.c:3009 [inline] do_last fs/namei.c:3427 [inline] path_openat+0x2308/0x2df0 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 -> #1 (&ovl_i_mutex_key[depth]#2){+.+.}: inode_lock include/linux/fs.h:748 [inline] process_measurement+0x926/0x1440 security/integrity/ima/ima_main.c:205 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:391 do_last fs/namei.c:3425 [inline] path_openat+0x7e4/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_open_execat+0x11d/0x5b0 fs/exec.c:853 open_exec+0x42/0x70 fs/exec.c:885 load_script+0x5d7/0x8a0 fs/binfmt_script.c:140 search_binary_handler.part.0+0xf9/0x4e0 fs/exec.c:1655 search_binary_handler fs/exec.c:1644 [inline] exec_binprm fs/exec.c:1697 [inline] __do_execve_file+0x1357/0x2360 fs/exec.c:1819 do_execveat_common fs/exec.c:1866 [inline] do_execveat+0x3d/0x50 fs/exec.c:1894 __do_sys_execveat fs/exec.c:1975 [inline] __se_sys_execveat fs/exec.c:1967 [inline] __x64_sys_execveat+0xe1/0x120 fs/exec.c:1967 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sig->cred_guard_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xd7/0x1260 kernel/locking/mutex.c:1072 do_io_accounting fs/proc/base.c:2737 [inline] proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2780 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4be/0x1160 fs/seq_file.c:229 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 do_preadv fs/read_write.c:1071 [inline] __do_sys_preadv fs/read_write.c:1121 [inline] __se_sys_preadv fs/read_write.c:1116 [inline] __x64_sys_preadv+0x22b/0x310 fs/read_write.c:1116 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: &sig->cred_guard_mutex --> sb_writers#3 --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#3); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 1 lock held by syz-executor.2/22598: #0: 00000000cb7d0a15 (&p->lock){+.+.}, at: seq_read+0x6b/0x1160 fs/seq_file.c:161 stack backtrace: CPU: 1 PID: 22598 Comm: syz-executor.2 Not tainted 4.19.154-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/0x2fe lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1221 check_prev_add kernel/locking/lockdep.c:1865 [inline] check_prevs_add kernel/locking/lockdep.c:1978 [inline] validate_chain kernel/locking/lockdep.c:2419 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3415 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3907 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xd7/0x1260 kernel/locking/mutex.c:1072 do_io_accounting fs/proc/base.c:2737 [inline] proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2780 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4be/0x1160 fs/seq_file.c:229 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 do_preadv fs/read_write.c:1071 [inline] __do_sys_preadv fs/read_write.c:1121 [inline] __se_sys_preadv fs/read_write.c:1116 [inline] __x64_sys_preadv+0x22b/0x310 fs/read_write.c:1116 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45deb9 Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007faf9db56c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000025e40 RCX: 000000000045deb9 RDX: 0000000000000001 RSI: 00000000200005c0 RDI: 0000000000000003 RBP: 000000000118bf70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007fff5d16701f R14: 00007faf9db579c0 R15: 000000000118bf2c netlink: 'syz-executor.4': attribute type 3 has an invalid length. netlink: 'syz-executor.4': attribute type 2 has an invalid length. netlink: 'syz-executor.4': attribute type 3 has an invalid length. netlink: 'syz-executor.4': attribute type 2 has an invalid length. netlink: 'syz-executor.4': attribute type 3 has an invalid length. netlink: 'syz-executor.4': attribute type 2 has an invalid length. netlink: 'syz-executor.4': attribute type 3 has an invalid length. netlink: 'syz-executor.4': attribute type 2 has an invalid length. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. xt_CT: You must specify a L4 protocol and not use inversions on it netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'. xt_CT: You must specify a L4 protocol and not use inversions on it UDF-fs: INFO Mounting volume 'LinuxUDF', timestamp 2020/09/19 18:44 (1000) xt_CT: You must specify a L4 protocol and not use inversions on it xt_CT: You must specify a L4 protocol and not use inversions on it