Dmitry, Please stop syzbot from playing with the SCHED_FIFO setting. We're being inundated with these useless bug reports. On Tue, Jan 11, 2022 at 10:15:26AM +0800, cruise k wrote: > Hi, > > Syzkaller found the following issue: > > HEAD commit: 75acfdb Linux 5.16-rc8 > git tree: upstream > console output: https://pastebin.com/raw/7TSe1kGF > kernel config: https://pastebin.com/raw/XsnKfdRt > > And hope the report log can help you. > > INFO: task systemd-udevd:27429 blocked for more than 146 seconds. > Not tainted 5.16.0-rc8+ #10 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:systemd-udevd state:D stack:26528 pid:27429 ppid: 3127 flags:0x00000000 > Call Trace: > <TASK> > context_switch kernel/sched/core.c:4972 [inline] > __schedule+0xcd9/0x2550 kernel/sched/core.c:6253 > schedule+0xd2/0x260 kernel/sched/core.c:6326 > rwsem_down_write_slowpath+0x664/0x1190 kernel/locking/rwsem.c:1151 > __down_write_common kernel/locking/rwsem.c:1268 [inline] > __down_write_common kernel/locking/rwsem.c:1265 [inline] > __down_write kernel/locking/rwsem.c:1277 [inline] > down_write+0x135/0x150 kernel/locking/rwsem.c:1524 > inode_lock include/linux/fs.h:783 [inline] > open_last_lookups fs/namei.c:3347 [inline] > path_openat+0xa66/0x26c0 fs/namei.c:3556 > do_filp_open+0x1c1/0x290 fs/namei.c:3586 > do_sys_openat2+0x61b/0x9a0 fs/open.c:1212 > do_sys_open+0xc3/0x140 fs/open.c:1228 > 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 > RIP: 0033:0x7fde8feb06f0 > RSP: 002b:00007ffdc8b61368 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fde8feb06f0 > RDX: 0000000000000180 RSI: 00000000000800c2 RDI: 00005624b8ca9880 > RBP: 000000000003a2f8 R08: 000000000000fefe R09: 00007fde8ff03740 > R10: 0000000000000000 R11: 0000000000000246 R12: 00005624b8ca9895 > R13: 8421084210842109 R14: 00000000000800c2 R15: 00007fde8ff3e540 > </TASK> > INFO: task systemd-udevd:27467 blocked for more than 148 seconds. > Not tainted 5.16.0-rc8+ #10 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:systemd-udevd state:D stack:27072 pid:27467 ppid: 3127 flags:0x00000000 > Call Trace: > <TASK> > context_switch kernel/sched/core.c:4972 [inline] > __schedule+0xcd9/0x2550 kernel/sched/core.c:6253 > schedule+0xd2/0x260 kernel/sched/core.c:6326 > rwsem_down_write_slowpath+0x664/0x1190 kernel/locking/rwsem.c:1151 > __down_write_common kernel/locking/rwsem.c:1268 [inline] > __down_write_common kernel/locking/rwsem.c:1265 [inline] > __down_write kernel/locking/rwsem.c:1277 [inline] > down_write+0x135/0x150 kernel/locking/rwsem.c:1524 > inode_lock include/linux/fs.h:783 [inline] > open_last_lookups fs/namei.c:3347 [inline] > path_openat+0xa66/0x26c0 fs/namei.c:3556 > do_filp_open+0x1c1/0x290 fs/namei.c:3586 > do_sys_openat2+0x61b/0x9a0 fs/open.c:1212 > do_sys_open+0xc3/0x140 fs/open.c:1228 > 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 > RIP: 0033:0x7fde8feb06f0 > RSP: 002b:00007ffdc8b60d78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fde8feb06f0 > RDX: 0000000000000180 RSI: 00000000000800c2 RDI: 00005624b8c989c0 > RBP: 000000000003a2f8 R08: 000000000000fcfe R09: 00007fde8ff03740 > R10: 0000000000000000 R11: 0000000000000246 R12: 00005624b8c989d6 > R13: 8421084210842109 R14: 00000000000800c2 R15: 00007fde8ff3e540 > </TASK> > INFO: task systemd-udevd:27515 blocked for more than 150 seconds. > Not tainted 5.16.0-rc8+ #10 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:systemd-udevd state:D stack:27584 pid:27515 ppid: 3127 flags:0x00004000 > Call Trace: > <TASK> > context_switch kernel/sched/core.c:4972 [inline] > __schedule+0xcd9/0x2550 kernel/sched/core.c:6253 > schedule+0xd2/0x260 kernel/sched/core.c:6326 > rwsem_down_write_slowpath+0x664/0x1190 kernel/locking/rwsem.c:1151 > __down_write_common kernel/locking/rwsem.c:1268 [inline] > __down_write_common kernel/locking/rwsem.c:1265 [inline] > __down_write kernel/locking/rwsem.c:1277 [inline] > down_write+0x135/0x150 kernel/locking/rwsem.c:1524 > inode_lock include/linux/fs.h:783 [inline] > open_last_lookups fs/namei.c:3347 [inline] > path_openat+0xa66/0x26c0 fs/namei.c:3556 > do_filp_open+0x1c1/0x290 fs/namei.c:3586 > do_sys_openat2+0x61b/0x9a0 fs/open.c:1212 > do_sys_open+0xc3/0x140 fs/open.c:1228 > 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 > RIP: 0033:0x7fde8feb06f0 > RSP: 002b:00007ffdc8b60d78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fde8feb06f0 > RDX: 0000000000000180 RSI: 00000000000800c2 RDI: 00005624b8cad110 > RBP: 000000000003a2f8 R08: 000000000000fefe R09: 00007fde8ff03740 > R10: 0000000000000000 R11: 0000000000000246 R12: 00005624b8cad126 > R13: 8421084210842109 R14: 00000000000800c2 R15: 00007fde8ff3e540 > </TASK> > INFO: task systemd-udevd:27530 blocked for more than 153 seconds. > Not tainted 5.16.0-rc8+ #10 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:systemd-udevd state:D stack:26048 pid:27530 ppid: 3127 flags:0x00000000 > Call Trace: > <TASK> > context_switch kernel/sched/core.c:4972 [inline] > __schedule+0xcd9/0x2550 kernel/sched/core.c:6253 > schedule+0xd2/0x260 kernel/sched/core.c:6326 > rwsem_down_write_slowpath+0x664/0x1190 kernel/locking/rwsem.c:1151 > __down_write_common kernel/locking/rwsem.c:1268 [inline] > __down_write_common kernel/locking/rwsem.c:1265 [inline] > __down_write kernel/locking/rwsem.c:1277 [inline] > down_write+0x135/0x150 kernel/locking/rwsem.c:1524 > inode_lock include/linux/fs.h:783 [inline] > open_last_lookups fs/namei.c:3347 [inline] > path_openat+0xa66/0x26c0 fs/namei.c:3556 > do_filp_open+0x1c1/0x290 fs/namei.c:3586 > do_sys_openat2+0x61b/0x9a0 fs/open.c:1212 > do_sys_open+0xc3/0x140 fs/open.c:1228 > 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 > RIP: 0033:0x7fde8feb06f0 > RSP: 002b:00007ffdc8b61368 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fde8feb06f0 > RDX: 0000000000000180 RSI: 00000000000800c2 RDI: 00005624b8ca9880 > RBP: 000000000003a2f8 R08: 000000000000fefe R09: 00007fde8ff03740 > R10: 0000000000000000 R11: 0000000000000246 R12: 00005624b8ca9896 > R13: 8421084210842109 R14: 00000000000800c2 R15: 00007fde8ff3e540 > </TASK>
