====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/22646 is trying to acquire lock: 000000003f4a7c45 (&sig->cred_guard_mutex){+.+.}, at: do_io_accounting fs/proc/base.c:2750 [inline] 000000003f4a7c45 (&sig->cred_guard_mutex){+.+.}, at: proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 but task is already holding lock: 00000000ebb9ea02 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: seq_read+0x6b/0x11c0 fs/seq_file.c:164 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_rename+0x22b/0x1a50 fs/overlayfs/dir.c:1084 vfs_rename+0x67e/0x1bc0 fs/namei.c:4479 do_renameat2+0xb59/0xc70 fs/namei.c:4629 __do_sys_rename fs/namei.c:4675 [inline] __se_sys_rename fs/namei.c:4673 [inline] __x64_sys_rename+0x5d/0x80 fs/namei.c:4673 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_dir_key[depth]){++++}: 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 -> #0 (&sig->cred_guard_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:937 [inline] __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078 do_io_accounting fs/proc/base.c:2750 [inline] proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 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 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 *** 2 locks held by syz-executor.4/22646: #0: 000000005c02d4e9 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 #1: 00000000ebb9ea02 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 stack backtrace: CPU: 1 PID: 22646 Comm: syz-executor.4 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_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 __mutex_lock_common kernel/locking/mutex.c:937 [inline] __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078 do_io_accounting fs/proc/base.c:2750 [inline] proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 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 RIP: 0033:0x7f7797d62059 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:00007f77966d7168 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f7797e74f60 RCX: 00007f7797d62059 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f7797dbc08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff0033417f R14: 00007f77966d7300 R15: 0000000000022000 audit: type=1800 audit(1644232432.469:790): pid=22657 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.2" name="bus" dev="sda1" ino=14114 res=0 IPVS: ftp: loaded support on port[0] = 21 audit: type=1804 audit(1644232432.499:791): pid=22657 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.2" name="/root/syzkaller-testdir367469172/syzkaller.A8goSJ/1092/bus" dev="sda1" ino=14114 res=1 audit: type=1804 audit(1644232432.499:792): pid=22657 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.2" name="/root/syzkaller-testdir367469172/syzkaller.A8goSJ/1092/bus" dev="sda1" ino=14114 res=1 audit: type=1400 audit(1644232432.799:793): apparmor="DENIED" operation="change_onexec" info="label not found" error=-2 profile="unconfined" name=7D70726D992F7468726561642D73652F617474722F656C05 pid=22722 comm="syz-executor.2" MTD: Attempt to mount non-MTD device "/dev/loop3" romfs: VFS: Can't find a romfs filesystem on dev loop3. MTD: Attempt to mount non-MTD device "/dev/loop3" romfs: VFS: Can't find a romfs filesystem on dev loop3. MTD: Attempt to mount non-MTD device "/dev/loop3" romfs: VFS: Can't find a romfs filesystem on dev loop3. MTD: Attempt to mount non-MTD device "/dev/loop3" romfs: VFS: Can't find a romfs filesystem on dev loop3. MTD: Attempt to mount non-MTD device "/dev/loop3" romfs: VFS: Can't find a romfs filesystem on dev loop3. MTD: Attempt to mount non-MTD device "/dev/loop3" romfs: VFS: Can't find a romfs filesystem on dev loop3. PM: Marking nosave pages: [mem 0x00000000-0x00000fff] netlink: 60 bytes leftover after parsing attributes in process `syz-executor.1'. PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] PM: Basic memory bitmaps created PM: Basic memory bitmaps freed netlink: 60 bytes leftover after parsing attributes in process `syz-executor.1'. PM: Marking nosave pages: [mem 0x00000000-0x00000fff] PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] PM: Basic memory bitmaps created PM: Basic memory bitmaps freed PM: Marking nosave pages: [mem 0x00000000-0x00000fff] PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] PM: Basic memory bitmaps created PM: Basic memory bitmaps freed netlink: 28 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 60 bytes leftover after parsing attributes in process `syz-executor.1'. netlink: 28 bytes leftover after parsing attributes in process `syz-executor.2'. x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING PM: Marking nosave pages: [mem 0x00000000-0x00000fff] PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] netlink: 28 bytes leftover after parsing attributes in process `syz-executor.2'. PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] PM: Basic memory bitmaps created netlink: 28 bytes leftover after parsing attributes in process `syz-executor.2'. PM: Basic memory bitmaps freed x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING PM: Marking nosave pages: [mem 0x00000000-0x00000fff] x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] PM: Basic memory bitmaps created x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING PM: Basic memory bitmaps freed PM: Marking nosave pages: [mem 0x00000000-0x00000fff] PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] PM: Basic memory bitmaps created PM: Basic memory bitmaps freed PM: Marking nosave pages: [mem 0x00000000-0x00000fff] PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING PM: Basic memory bitmaps created PM: Basic memory bitmaps freed PM: Marking nosave pages: [mem 0x00000000-0x00000fff] x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] PM: Basic memory bitmaps created