| Message ID | 1646377603-19730-1-git-send-email-byungchul.park@lge.com |
|---|---|
| Headers | show |
| Series | DEPT(Dependency Tracker) | expand |
On Fri, Mar 04, 2022 at 04:06:19PM +0900, Byungchul Park wrote: > Hi Linus and folks, > > I've been developing a tool for detecting deadlock possibilities by > tracking wait/event rather than lock(?) acquisition order to try to > cover all synchonization machanisms. It's done on v5.17-rc1 tag. > > https://github.com/lgebyungchulpark/linux-dept/commits/dept1.14_on_v5.17-rc1 > Small feedback unrelated to thread: I'm not sure "Need to expand the ring buffer" is something to call WARN(). Is this stack trace useful for something? ======== Hello Byungchul. These are two warnings of DEPT on system. Both cases look similar. In what case DEPT says (unknown)? I'm not sure we can properly debug this. =================================================== DEPT: Circular dependency has been detected. 5.17.0-rc1+ #3 Tainted: G W --------------------------------------------------- summary --------------------------------------------------- *** AA DEADLOCK *** context A [S] (unknown)(&vfork:0) [W] wait_for_completion_killable(&vfork:0) [E] complete(&vfork:0) [S]: start of the event context [W]: the wait blocked [E]: the event not reachable --------------------------------------------------- context A's detail --------------------------------------------------- context A [S] (unknown)(&vfork:0) [W] wait_for_completion_killable(&vfork:0) [E] complete(&vfork:0) [S] (unknown)(&vfork:0): (N/A) [W] wait_for_completion_killable(&vfork:0): [<ffffffc00802204c>] kernel_clone+0x25c/0x2b8 stacktrace: dept_wait+0x74/0x88 wait_for_completion_killable+0x60/0xa0 kernel_clone+0x25c/0x2b8 __do_sys_clone+0x5c/0x74 __arm64_sys_clone+0x18/0x20 invoke_syscall.constprop.0+0x78/0xc4 do_el0_svc+0x98/0xd0 el0_svc+0x44/0xe4 el0t_64_sync_handler+0xb0/0x12c el0t_64_sync+0x158/0x15c [E] complete(&vfork:0): [<ffffffc00801f49c>] mm_release+0x7c/0x90 stacktrace: dept_event+0xe0/0x100 complete+0x48/0x98 mm_release+0x7c/0x90 exit_mm_release+0xc/0x14 do_exit+0x1b4/0x81c do_group_exit+0x30/0x9c __wake_up_parent+0x0/0x24 invoke_syscall.constprop.0+0x78/0xc4 do_el0_svc+0x98/0xd0 el0_svc+0x44/0xe4 el0t_64_sync_handler+0xb0/0x12c el0t_64_sync+0x158/0x15c --------------------------------------------------- information that might be helpful --------------------------------------------------- CPU: 6 PID: 229 Comm: start-stop-daem Tainted: G W 5.17.0-rc1+ #3 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace.part.0+0x9c/0xc4 show_stack+0x14/0x28 dump_stack_lvl+0x9c/0xcc dump_stack+0x14/0x2c print_circle+0x2d4/0x438 cb_check_dl+0x44/0x70 bfs+0x60/0x168 add_dep+0x88/0x11c do_event.constprop.0+0x19c/0x2c0 dept_event+0xe0/0x100 complete+0x48/0x98 mm_release+0x7c/0x90 exit_mm_release+0xc/0x14 do_exit+0x1b4/0x81c do_group_exit+0x30/0x9c __wake_up_parent+0x0/0x24 invoke_syscall.constprop.0+0x78/0xc4 do_el0_svc+0x98/0xd0 el0_svc+0x44/0xe4 el0t_64_sync_handler+0xb0/0x12c el0t_64_sync+0x158/0x15c =================================================== DEPT: Circular dependency has been detected. 5.17.0-rc1+ #3 Tainted: G W --------------------------------------------------- summary --------------------------------------------------- *** AA DEADLOCK *** context A [S] (unknown)(&try_completion:0) [W] wait_for_completion_timeout(&try_completion:0) [E] complete(&try_completion:0) [S]: start of the event context [W]: the wait blocked [E]: the event not reachable --------------------------------------------------- context A's detail --------------------------------------------------- context A [S] (unknown)(&try_completion:0) [W] wait_for_completion_timeout(&try_completion:0) [E] complete(&try_completion:0) [S] (unknown)(&try_completion:0): (N/A) [W] wait_for_completion_timeout(&try_completion:0): [<ffffffc008166bf4>] kunit_try_catch_run+0xb4/0x160 stacktrace: dept_wait+0x74/0x88 wait_for_completion_timeout+0x64/0xa0 kunit_try_catch_run+0xb4/0x160 kunit_test_try_catch_successful_try_no_catch+0x3c/0x98 kunit_try_run_case+0x9c/0xa0 kunit_generic_run_threadfn_adapter+0x1c/0x28 kthread+0xd4/0xe4 ret_from_fork+0x10/0x20 [E] complete(&try_completion:0): [<ffffffc00803dce4>] kthread_complete_and_exit+0x18/0x20 stacktrace: dept_event+0xe0/0x100 complete+0x48/0x98 kthread_complete_and_exit+0x18/0x20 kunit_try_catch_throw+0x0/0x1c kthread+0xd4/0xe4 ret_from_fork+0x10/0x20 --------------------------------------------------- information that might be helpful --------------------------------------------------- CPU: 15 PID: 132 Comm: kunit_try_catch Tainted: G W 5.17.0-rc1+ #3 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace.part.0+0x9c/0xc4 show_stack+0x14/0x28 dump_stack_lvl+0x9c/0xcc dump_stack+0x14/0x2c print_circle+0x2d4/0x438 cb_check_dl+0x44/0x70 bfs+0x60/0x168 add_dep+0x88/0x11c do_event.constprop.0+0x19c/0x2c0 dept_event+0xe0/0x100 complete+0x48/0x98 kthread_complete_and_exit+0x18/0x20 kunit_try_catch_throw+0x0/0x1c kthread+0xd4/0xe4 ret_from_fork+0x10/0x20 > Benifit: > > 0. Works with all lock primitives. > 1. Works with wait_for_completion()/complete(). > 2. Works with 'wait' on PG_locked. > 3. Works with 'wait' on PG_writeback. > 4. Works with swait/wakeup. > 5. Works with waitqueue. > 6. Multiple reports are allowed. > 7. Deduplication control on multiple reports. > 8. Withstand false positives thanks to 6. > 9. Easy to tag any wait/event. > > Future work: [...] > -- > 1.9.1 >
On Sat, Mar 12, 2022 at 01:53:26AM +0000, Hyeonggon Yoo wrote: > On Fri, Mar 04, 2022 at 04:06:19PM +0900, Byungchul Park wrote: > > Hi Linus and folks, > > > > I've been developing a tool for detecting deadlock possibilities by > > tracking wait/event rather than lock(?) acquisition order to try to > > cover all synchonization machanisms. It's done on v5.17-rc1 tag. > > > > https://github.com/lgebyungchulpark/linux-dept/commits/dept1.14_on_v5.17-rc1 > > > > Small feedback unrelated to thread: > I'm not sure "Need to expand the ring buffer" is something to call > WARN(). Is this stack trace useful for something? Yeah. It seems to happen too often. I won't warn it. Thanks. > ======== > > Hello Byungchul. These are two warnings of DEPT on system. > Both cases look similar. > > In what case DEPT says (unknown)? > I'm not sure we can properly debug this. > > =================================================== > DEPT: Circular dependency has been detected. > 5.17.0-rc1+ #3 Tainted: G W > --------------------------------------------------- > summary > --------------------------------------------------- > *** AA DEADLOCK *** > > context A > [S] (unknown)(&vfork:0) > [W] wait_for_completion_killable(&vfork:0) > [E] complete(&vfork:0) All the reports look like having to do with kernel_clone(). I need to check it more. Thank you very much. You are awesome, Hyeonggon. Thank you, Byungchul > [S]: start of the event context > [W]: the wait blocked > [E]: the event not reachable > --------------------------------------------------- > context A's detail > --------------------------------------------------- > context A > [S] (unknown)(&vfork:0) > [W] wait_for_completion_killable(&vfork:0) > [E] complete(&vfork:0) > > [S] (unknown)(&vfork:0): > (N/A) > > [W] wait_for_completion_killable(&vfork:0): > [<ffffffc00802204c>] kernel_clone+0x25c/0x2b8 > stacktrace: > dept_wait+0x74/0x88 > wait_for_completion_killable+0x60/0xa0 > kernel_clone+0x25c/0x2b8 > __do_sys_clone+0x5c/0x74 > __arm64_sys_clone+0x18/0x20 > invoke_syscall.constprop.0+0x78/0xc4 > do_el0_svc+0x98/0xd0 > el0_svc+0x44/0xe4 > el0t_64_sync_handler+0xb0/0x12c > el0t_64_sync+0x158/0x15c > > [E] complete(&vfork:0): > [<ffffffc00801f49c>] mm_release+0x7c/0x90 > stacktrace: > dept_event+0xe0/0x100 > complete+0x48/0x98 > mm_release+0x7c/0x90 > exit_mm_release+0xc/0x14 > do_exit+0x1b4/0x81c > do_group_exit+0x30/0x9c > __wake_up_parent+0x0/0x24 > invoke_syscall.constprop.0+0x78/0xc4 > do_el0_svc+0x98/0xd0 > el0_svc+0x44/0xe4 > el0t_64_sync_handler+0xb0/0x12c > el0t_64_sync+0x158/0x15c > --------------------------------------------------- > information that might be helpful > --------------------------------------------------- > CPU: 6 PID: 229 Comm: start-stop-daem Tainted: G W 5.17.0-rc1+ #3 > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace.part.0+0x9c/0xc4 > show_stack+0x14/0x28 > dump_stack_lvl+0x9c/0xcc > dump_stack+0x14/0x2c > print_circle+0x2d4/0x438 > cb_check_dl+0x44/0x70 > bfs+0x60/0x168 > add_dep+0x88/0x11c > do_event.constprop.0+0x19c/0x2c0 > dept_event+0xe0/0x100 > complete+0x48/0x98 > mm_release+0x7c/0x90 > exit_mm_release+0xc/0x14 > do_exit+0x1b4/0x81c > do_group_exit+0x30/0x9c > __wake_up_parent+0x0/0x24 > invoke_syscall.constprop.0+0x78/0xc4 > do_el0_svc+0x98/0xd0 > el0_svc+0x44/0xe4 > el0t_64_sync_handler+0xb0/0x12c > el0t_64_sync+0x158/0x15c > > > > > =================================================== > DEPT: Circular dependency has been detected. > 5.17.0-rc1+ #3 Tainted: G W > --------------------------------------------------- > summary > --------------------------------------------------- > *** AA DEADLOCK *** > > context A > [S] (unknown)(&try_completion:0) > [W] wait_for_completion_timeout(&try_completion:0) > [E] complete(&try_completion:0) > > [S]: start of the event context > [W]: the wait blocked > [E]: the event not reachable > --------------------------------------------------- > context A's detail > --------------------------------------------------- > context A > [S] (unknown)(&try_completion:0) > [W] wait_for_completion_timeout(&try_completion:0) > [E] complete(&try_completion:0) > > [S] (unknown)(&try_completion:0): > (N/A) > > [W] wait_for_completion_timeout(&try_completion:0): > [<ffffffc008166bf4>] kunit_try_catch_run+0xb4/0x160 > stacktrace: > dept_wait+0x74/0x88 > wait_for_completion_timeout+0x64/0xa0 > kunit_try_catch_run+0xb4/0x160 > kunit_test_try_catch_successful_try_no_catch+0x3c/0x98 > kunit_try_run_case+0x9c/0xa0 > kunit_generic_run_threadfn_adapter+0x1c/0x28 > kthread+0xd4/0xe4 > ret_from_fork+0x10/0x20 > > [E] complete(&try_completion:0): > [<ffffffc00803dce4>] kthread_complete_and_exit+0x18/0x20 > stacktrace: > dept_event+0xe0/0x100 > complete+0x48/0x98 > kthread_complete_and_exit+0x18/0x20 > kunit_try_catch_throw+0x0/0x1c > kthread+0xd4/0xe4 > ret_from_fork+0x10/0x20 > > --------------------------------------------------- > information that might be helpful > --------------------------------------------------- > CPU: 15 PID: 132 Comm: kunit_try_catch Tainted: G W 5.17.0-rc1+ #3 > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace.part.0+0x9c/0xc4 > show_stack+0x14/0x28 > dump_stack_lvl+0x9c/0xcc > dump_stack+0x14/0x2c > print_circle+0x2d4/0x438 > cb_check_dl+0x44/0x70 > bfs+0x60/0x168 > add_dep+0x88/0x11c > do_event.constprop.0+0x19c/0x2c0 > dept_event+0xe0/0x100 > complete+0x48/0x98 > kthread_complete_and_exit+0x18/0x20 > kunit_try_catch_throw+0x0/0x1c > kthread+0xd4/0xe4 > ret_from_fork+0x10/0x20 > -- > Thank you, You are awesome! > Hyeonggon :-)
On Mon, Mar 14, 2022 at 03:59:06PM +0900, Byungchul Park wrote: > On Sat, Mar 12, 2022 at 01:53:26AM +0000, Hyeonggon Yoo wrote: > > On Fri, Mar 04, 2022 at 04:06:19PM +0900, Byungchul Park wrote: > > > Hi Linus and folks, > > > > > > I've been developing a tool for detecting deadlock possibilities by > > > tracking wait/event rather than lock(?) acquisition order to try to > > > cover all synchonization machanisms. It's done on v5.17-rc1 tag. > > > > > > https://github.com/lgebyungchulpark/linux-dept/commits/dept1.14_on_v5.17-rc1 > > > > > > > Small feedback unrelated to thread: > > I'm not sure "Need to expand the ring buffer" is something to call > > WARN(). Is this stack trace useful for something? > > Yeah. It seems to happen too often. I won't warn it. Thanks. Thanks! > > ======== > > > > Hello Byungchul. These are two warnings of DEPT on system. > > Both cases look similar. > > > > In what case DEPT says (unknown)? > > I'm not sure we can properly debug this. > > > > =================================================== > > DEPT: Circular dependency has been detected. > > 5.17.0-rc1+ #3 Tainted: G W > > --------------------------------------------------- > > summary > > --------------------------------------------------- > > *** AA DEADLOCK *** > > > > context A > > [S] (unknown)(&vfork:0) > > [W] wait_for_completion_killable(&vfork:0) > > [E] complete(&vfork:0) > > All the reports look like having to do with kernel_clone(). I need to > check it more. Thank you very much. > > You are awesome, Hyeonggon. > Thank you. Let me know if there is something I can help! > Thank you, > Byungchul > > > [S]: start of the event context > > [W]: the wait blocked > > [E]: the event not reachable > > --------------------------------------------------- > > context A's detail > > --------------------------------------------------- > > context A > > [S] (unknown)(&vfork:0) > > [W] wait_for_completion_killable(&vfork:0) > > [E] complete(&vfork:0) > > > > [S] (unknown)(&vfork:0): > > (N/A) > > > > [W] wait_for_completion_killable(&vfork:0): > > [<ffffffc00802204c>] kernel_clone+0x25c/0x2b8 > > stacktrace: > > dept_wait+0x74/0x88 > > wait_for_completion_killable+0x60/0xa0 > > kernel_clone+0x25c/0x2b8 > > __do_sys_clone+0x5c/0x74 > > __arm64_sys_clone+0x18/0x20 > > invoke_syscall.constprop.0+0x78/0xc4 > > do_el0_svc+0x98/0xd0 > > el0_svc+0x44/0xe4 > > el0t_64_sync_handler+0xb0/0x12c > > el0t_64_sync+0x158/0x15c > > > > [E] complete(&vfork:0): > > [<ffffffc00801f49c>] mm_release+0x7c/0x90 > > stacktrace: > > dept_event+0xe0/0x100 > > complete+0x48/0x98 > > mm_release+0x7c/0x90 > > exit_mm_release+0xc/0x14 > > do_exit+0x1b4/0x81c > > do_group_exit+0x30/0x9c > > __wake_up_parent+0x0/0x24 > > invoke_syscall.constprop.0+0x78/0xc4 > > do_el0_svc+0x98/0xd0 > > el0_svc+0x44/0xe4 > > el0t_64_sync_handler+0xb0/0x12c > > el0t_64_sync+0x158/0x15c > > --------------------------------------------------- > > information that might be helpful > > --------------------------------------------------- > > CPU: 6 PID: 229 Comm: start-stop-daem Tainted: G W 5.17.0-rc1+ #3 > > Hardware name: linux,dummy-virt (DT) > > Call trace: > > dump_backtrace.part.0+0x9c/0xc4 > > show_stack+0x14/0x28 > > dump_stack_lvl+0x9c/0xcc > > dump_stack+0x14/0x2c > > print_circle+0x2d4/0x438 > > cb_check_dl+0x44/0x70 > > bfs+0x60/0x168 > > add_dep+0x88/0x11c > > do_event.constprop.0+0x19c/0x2c0 > > dept_event+0xe0/0x100 > > complete+0x48/0x98 > > mm_release+0x7c/0x90 > > exit_mm_release+0xc/0x14 > > do_exit+0x1b4/0x81c > > do_group_exit+0x30/0x9c > > __wake_up_parent+0x0/0x24 > > invoke_syscall.constprop.0+0x78/0xc4 > > do_el0_svc+0x98/0xd0 > > el0_svc+0x44/0xe4 > > el0t_64_sync_handler+0xb0/0x12c > > el0t_64_sync+0x158/0x15c > > > > > > > > > > =================================================== > > DEPT: Circular dependency has been detected. > > 5.17.0-rc1+ #3 Tainted: G W > > --------------------------------------------------- > > summary > > --------------------------------------------------- > > *** AA DEADLOCK *** > > > > context A > > [S] (unknown)(&try_completion:0) > > [W] wait_for_completion_timeout(&try_completion:0) > > [E] complete(&try_completion:0) > > > > [S]: start of the event context > > [W]: the wait blocked > > [E]: the event not reachable > > --------------------------------------------------- > > context A's detail > > --------------------------------------------------- > > context A > > [S] (unknown)(&try_completion:0) > > [W] wait_for_completion_timeout(&try_completion:0) > > [E] complete(&try_completion:0) > > > > [S] (unknown)(&try_completion:0): > > (N/A) > > > > [W] wait_for_completion_timeout(&try_completion:0): > > [<ffffffc008166bf4>] kunit_try_catch_run+0xb4/0x160 > > stacktrace: > > dept_wait+0x74/0x88 > > wait_for_completion_timeout+0x64/0xa0 > > kunit_try_catch_run+0xb4/0x160 > > kunit_test_try_catch_successful_try_no_catch+0x3c/0x98 > > kunit_try_run_case+0x9c/0xa0 > > kunit_generic_run_threadfn_adapter+0x1c/0x28 > > kthread+0xd4/0xe4 > > ret_from_fork+0x10/0x20 > > > > [E] complete(&try_completion:0): > > [<ffffffc00803dce4>] kthread_complete_and_exit+0x18/0x20 > > stacktrace: > > dept_event+0xe0/0x100 > > complete+0x48/0x98 > > kthread_complete_and_exit+0x18/0x20 > > kunit_try_catch_throw+0x0/0x1c > > kthread+0xd4/0xe4 > > ret_from_fork+0x10/0x20 > > > > --------------------------------------------------- > > information that might be helpful > > --------------------------------------------------- > > CPU: 15 PID: 132 Comm: kunit_try_catch Tainted: G W 5.17.0-rc1+ #3 > > Hardware name: linux,dummy-virt (DT) > > Call trace: > > dump_backtrace.part.0+0x9c/0xc4 > > show_stack+0x14/0x28 > > dump_stack_lvl+0x9c/0xcc > > dump_stack+0x14/0x2c > > print_circle+0x2d4/0x438 > > cb_check_dl+0x44/0x70 > > bfs+0x60/0x168 > > add_dep+0x88/0x11c > > do_event.constprop.0+0x19c/0x2c0 > > dept_event+0xe0/0x100 > > complete+0x48/0x98 > > kthread_complete_and_exit+0x18/0x20 > > kunit_try_catch_throw+0x0/0x1c > > kthread+0xd4/0xe4 > > ret_from_fork+0x10/0x20 > > > > -- > > Thank you, You are awesome! > > Hyeonggon :-)
On Sat, Mar 12, 2022 at 01:53:26AM +0000, Hyeonggon Yoo wrote: > On Fri, Mar 04, 2022 at 04:06:19PM +0900, Byungchul Park wrote: > > Hi Linus and folks, > > > > I've been developing a tool for detecting deadlock possibilities by > > tracking wait/event rather than lock(?) acquisition order to try to > > cover all synchonization machanisms. It's done on v5.17-rc1 tag. > > > > https://github.com/lgebyungchulpark/linux-dept/commits/dept1.14_on_v5.17-rc1 > > > > Small feedback unrelated to thread: > I'm not sure "Need to expand the ring buffer" is something to call > WARN(). Is this stack trace useful for something? > ======== > > Hello Byungchul. These are two warnings of DEPT on system. Hi Hyeonggon, Could you run scripts/decode_stacktrace.sh and share the result instead of the raw format below if the reports still appear with PATCH v5? It'd be appreciated (: https://lkml.org/lkml/2022/3/15/1277 (or https://github.com/lgebyungchulpark/linux-dept/commits/dept1.18_on_v5.17-rc7) Thank you very much! -- Byungchul > Both cases look similar. > > In what case DEPT says (unknown)? > I'm not sure we can properly debug this. > > =================================================== > DEPT: Circular dependency has been detected. > 5.17.0-rc1+ #3 Tainted: G W > --------------------------------------------------- > summary > --------------------------------------------------- > *** AA DEADLOCK *** > > context A > [S] (unknown)(&vfork:0) > [W] wait_for_completion_killable(&vfork:0) > [E] complete(&vfork:0) > > [S]: start of the event context > [W]: the wait blocked > [E]: the event not reachable > --------------------------------------------------- > context A's detail > --------------------------------------------------- > context A > [S] (unknown)(&vfork:0) > [W] wait_for_completion_killable(&vfork:0) > [E] complete(&vfork:0) > > [S] (unknown)(&vfork:0): > (N/A) > > [W] wait_for_completion_killable(&vfork:0): > [<ffffffc00802204c>] kernel_clone+0x25c/0x2b8 > stacktrace: > dept_wait+0x74/0x88 > wait_for_completion_killable+0x60/0xa0 > kernel_clone+0x25c/0x2b8 > __do_sys_clone+0x5c/0x74 > __arm64_sys_clone+0x18/0x20 > invoke_syscall.constprop.0+0x78/0xc4 > do_el0_svc+0x98/0xd0 > el0_svc+0x44/0xe4 > el0t_64_sync_handler+0xb0/0x12c > el0t_64_sync+0x158/0x15c > > [E] complete(&vfork:0): > [<ffffffc00801f49c>] mm_release+0x7c/0x90 > stacktrace: > dept_event+0xe0/0x100 > complete+0x48/0x98 > mm_release+0x7c/0x90 > exit_mm_release+0xc/0x14 > do_exit+0x1b4/0x81c > do_group_exit+0x30/0x9c > __wake_up_parent+0x0/0x24 > invoke_syscall.constprop.0+0x78/0xc4 > do_el0_svc+0x98/0xd0 > el0_svc+0x44/0xe4 > el0t_64_sync_handler+0xb0/0x12c > el0t_64_sync+0x158/0x15c > --------------------------------------------------- > information that might be helpful > --------------------------------------------------- > CPU: 6 PID: 229 Comm: start-stop-daem Tainted: G W 5.17.0-rc1+ #3 > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace.part.0+0x9c/0xc4 > show_stack+0x14/0x28 > dump_stack_lvl+0x9c/0xcc > dump_stack+0x14/0x2c > print_circle+0x2d4/0x438 > cb_check_dl+0x44/0x70 > bfs+0x60/0x168 > add_dep+0x88/0x11c > do_event.constprop.0+0x19c/0x2c0 > dept_event+0xe0/0x100 > complete+0x48/0x98 > mm_release+0x7c/0x90 > exit_mm_release+0xc/0x14 > do_exit+0x1b4/0x81c > do_group_exit+0x30/0x9c > __wake_up_parent+0x0/0x24 > invoke_syscall.constprop.0+0x78/0xc4 > do_el0_svc+0x98/0xd0 > el0_svc+0x44/0xe4 > el0t_64_sync_handler+0xb0/0x12c > el0t_64_sync+0x158/0x15c > > > > > =================================================== > DEPT: Circular dependency has been detected. > 5.17.0-rc1+ #3 Tainted: G W > --------------------------------------------------- > summary > --------------------------------------------------- > *** AA DEADLOCK *** > > context A > [S] (unknown)(&try_completion:0) > [W] wait_for_completion_timeout(&try_completion:0) > [E] complete(&try_completion:0) > > [S]: start of the event context > [W]: the wait blocked > [E]: the event not reachable > --------------------------------------------------- > context A's detail > --------------------------------------------------- > context A > [S] (unknown)(&try_completion:0) > [W] wait_for_completion_timeout(&try_completion:0) > [E] complete(&try_completion:0) > > [S] (unknown)(&try_completion:0): > (N/A) > > [W] wait_for_completion_timeout(&try_completion:0): > [<ffffffc008166bf4>] kunit_try_catch_run+0xb4/0x160 > stacktrace: > dept_wait+0x74/0x88 > wait_for_completion_timeout+0x64/0xa0 > kunit_try_catch_run+0xb4/0x160 > kunit_test_try_catch_successful_try_no_catch+0x3c/0x98 > kunit_try_run_case+0x9c/0xa0 > kunit_generic_run_threadfn_adapter+0x1c/0x28 > kthread+0xd4/0xe4 > ret_from_fork+0x10/0x20 > > [E] complete(&try_completion:0): > [<ffffffc00803dce4>] kthread_complete_and_exit+0x18/0x20 > stacktrace: > dept_event+0xe0/0x100 > complete+0x48/0x98 > kthread_complete_and_exit+0x18/0x20 > kunit_try_catch_throw+0x0/0x1c > kthread+0xd4/0xe4 > ret_from_fork+0x10/0x20 > > --------------------------------------------------- > information that might be helpful > --------------------------------------------------- > CPU: 15 PID: 132 Comm: kunit_try_catch Tainted: G W 5.17.0-rc1+ #3 > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace.part.0+0x9c/0xc4 > show_stack+0x14/0x28 > dump_stack_lvl+0x9c/0xcc > dump_stack+0x14/0x2c > print_circle+0x2d4/0x438 > cb_check_dl+0x44/0x70 > bfs+0x60/0x168 > add_dep+0x88/0x11c > do_event.constprop.0+0x19c/0x2c0 > dept_event+0xe0/0x100 > complete+0x48/0x98 > kthread_complete_and_exit+0x18/0x20 > kunit_try_catch_throw+0x0/0x1c > kthread+0xd4/0xe4 > ret_from_fork+0x10/0x20 > > > > Benifit: > > > > 0. Works with all lock primitives. > > 1. Works with wait_for_completion()/complete(). > > 2. Works with 'wait' on PG_locked. > > 3. Works with 'wait' on PG_writeback. > > 4. Works with swait/wakeup. > > 5. Works with waitqueue. > > 6. Multiple reports are allowed. > > 7. Deduplication control on multiple reports. > > 8. Withstand false positives thanks to 6. > > 9. Easy to tag any wait/event. > > > > Future work: > > [...] > > > -- > > 1.9.1 > > > > -- > Thank you, You are awesome! > Hyeonggon :-)
On Wed, Mar 16, 2022 at 01:32:13PM +0900, Byungchul Park wrote: > On Sat, Mar 12, 2022 at 01:53:26AM +0000, Hyeonggon Yoo wrote: > > On Fri, Mar 04, 2022 at 04:06:19PM +0900, Byungchul Park wrote: > > > Hi Linus and folks, > > > > > > I've been developing a tool for detecting deadlock possibilities by > > > tracking wait/event rather than lock(?) acquisition order to try to > > > cover all synchonization machanisms. It's done on v5.17-rc1 tag. > > > > > > https://github.com/lgebyungchulpark/linux-dept/commits/dept1.14_on_v5.17-rc1 > > > > > > > Small feedback unrelated to thread: > > I'm not sure "Need to expand the ring buffer" is something to call > > WARN(). Is this stack trace useful for something? > > ======== > > > > Hello Byungchul. These are two warnings of DEPT on system. > > Hi Hyeonggon, > > Could you run scripts/decode_stacktrace.sh and share the result instead > of the raw format below if the reports still appear with PATCH v5? It'd > be appreciated (: > Hi Byungchul. on dept1.18_on_v5.17-rc7, the kernel_clone() warning has gone. There is one warning remaining on my system: It warns when running kunit-try-catch-test testcase. =================================================== DEPT: Circular dependency has been detected. 5.17.0-rc7+ #4 Not tainted --------------------------------------------------- summary --------------------------------------------------- *** AA DEADLOCK *** context A [S] (unknown)(&try_completion:0) [W] wait_for_completion_timeout(&try_completion:0) [E] complete(&try_completion:0) [S]: start of the event context [W]: the wait blocked [E]: the event not reachable --------------------------------------------------- context A's detail --------------------------------------------------- context A [S] (unknown)(&try_completion:0) [W] wait_for_completion_timeout(&try_completion:0) [E] complete(&try_completion:0) [S] (unknown)(&try_completion:0): (N/A) [W] wait_for_completion_timeout(&try_completion:0): kunit_try_catch_run (lib/kunit/try-catch.c:78 (discriminator 1)) stacktrace: dept_wait (kernel/dependency/dept.c:2149) wait_for_completion_timeout (kernel/sched/completion.c:119 (discriminator 4) kernel/sched/completion.c:165 (discriminator 4)) kunit_try_catch_run (lib/kunit/try-catch.c:78 (discriminator 1)) kunit_test_try_catch_successful_try_no_catch (lib/kunit/kunit-test.c:43) kunit_try_run_case (lib/kunit/test.c:333 lib/kunit/test.c:374) kunit_generic_run_threadfn_adapter (lib/kunit/try-catch.c:30) kthread (kernel/kthread.c:379) ret_from_fork (arch/arm64/kernel/entry.S:757) [E] complete(&try_completion:0): kthread_complete_and_exit (kernel/kthread.c:327) stacktrace: dept_event (kernel/dependency/dept.c:2376 (discriminator 2)) complete (kernel/sched/completion.c:33 (discriminator 4)) kthread_complete_and_exit (kernel/kthread.c:327) kunit_try_catch_throw (lib/kunit/try-catch.c:18) kthread (kernel/kthread.c:379) ret_from_fork (arch/arm64/kernel/entry.S:757) --------------------------------------------------- information that might be helpful --------------------------------------------------- Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace.part.0 (arch/arm64/kernel/stacktrace.c:186) show_stack (arch/arm64/kernel/stacktrace.c:193) dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4)) dump_stack (lib/dump_stack.c:114) print_circle (./arch/arm64/include/asm/atomic_ll_sc.h:112 ./arch/arm64/include/asm/atomic.h:30 ./include/linux/atomic/atomic-arch-fallback.h:511 ./include/linux/atomic/atomic-instrumented.h:258 kernel/dependency/dept.c:140 kernel/dependency/dept.c:748) cb_check_dl (kernel/dependency/dept.c:1083 kernel/dependency/dept.c:1064) bfs (kernel/dependency/dept.c:833) add_dep (kernel/dependency/dept.c:1409) do_event (kernel/dependency/dept.c:175 kernel/dependency/dept.c:1644) dept_event (kernel/dependency/dept.c:2376 (discriminator 2)) complete (kernel/sched/completion.c:33 (discriminator 4)) kthread_complete_and_exit (kernel/kthread.c:327) kunit_try_catch_throw (lib/kunit/try-catch.c:18) kthread (kernel/kthread.c:379) ret_from_fork (arch/arm64/kernel/entry.S:757)
On Wed, Mar 16, 2022 at 09:30:02AM +0000, Hyeonggon Yoo wrote: > On Wed, Mar 16, 2022 at 01:32:13PM +0900, Byungchul Park wrote: > > On Sat, Mar 12, 2022 at 01:53:26AM +0000, Hyeonggon Yoo wrote: > > > On Fri, Mar 04, 2022 at 04:06:19PM +0900, Byungchul Park wrote: > > > > Hi Linus and folks, > > > > > > > > I've been developing a tool for detecting deadlock possibilities by > > > > tracking wait/event rather than lock(?) acquisition order to try to > > > > cover all synchonization machanisms. It's done on v5.17-rc1 tag. > > > > > > > > https://github.com/lgebyungchulpark/linux-dept/commits/dept1.14_on_v5.17-rc1 > > > > > > > > > > Small feedback unrelated to thread: > > > I'm not sure "Need to expand the ring buffer" is something to call > > > WARN(). Is this stack trace useful for something? > > > ======== > > > > > > Hello Byungchul. These are two warnings of DEPT on system. > > > > Hi Hyeonggon, > > > > Could you run scripts/decode_stacktrace.sh and share the result instead > > of the raw format below if the reports still appear with PATCH v5? It'd > > be appreciated (: > > > > Hi Byungchul. > > on dept1.18_on_v5.17-rc7, the kernel_clone() warning has gone. > There is one warning remaining on my system: > > It warns when running kunit-try-catch-test testcase. Hi Hyeonggon, I can reproduce it thanks to you. I will let you know on all works done. Thanks, Byungchul > =================================================== > DEPT: Circular dependency has been detected. > 5.17.0-rc7+ #4 Not tainted > --------------------------------------------------- > summary > --------------------------------------------------- > *** AA DEADLOCK *** > > context A > [S] (unknown)(&try_completion:0) > [W] wait_for_completion_timeout(&try_completion:0) > [E] complete(&try_completion:0) > > [S]: start of the event context > [W]: the wait blocked > [E]: the event not reachable > --------------------------------------------------- > context A's detail > --------------------------------------------------- > context A > [S] (unknown)(&try_completion:0) > [W] wait_for_completion_timeout(&try_completion:0) > [E] complete(&try_completion:0) > > [S] (unknown)(&try_completion:0): > (N/A) > > [W] wait_for_completion_timeout(&try_completion:0): > kunit_try_catch_run (lib/kunit/try-catch.c:78 (discriminator 1)) > stacktrace: > dept_wait (kernel/dependency/dept.c:2149) > wait_for_completion_timeout (kernel/sched/completion.c:119 (discriminator 4) kernel/sched/completion.c:165 (discriminator 4)) > kunit_try_catch_run (lib/kunit/try-catch.c:78 (discriminator 1)) > kunit_test_try_catch_successful_try_no_catch (lib/kunit/kunit-test.c:43) > kunit_try_run_case (lib/kunit/test.c:333 lib/kunit/test.c:374) > kunit_generic_run_threadfn_adapter (lib/kunit/try-catch.c:30) > kthread (kernel/kthread.c:379) > ret_from_fork (arch/arm64/kernel/entry.S:757) > > [E] complete(&try_completion:0): > kthread_complete_and_exit (kernel/kthread.c:327) > stacktrace: > dept_event (kernel/dependency/dept.c:2376 (discriminator 2)) > complete (kernel/sched/completion.c:33 (discriminator 4)) > kthread_complete_and_exit (kernel/kthread.c:327) > kunit_try_catch_throw (lib/kunit/try-catch.c:18) > kthread (kernel/kthread.c:379) > ret_from_fork (arch/arm64/kernel/entry.S:757) > > --------------------------------------------------- > information that might be helpful > --------------------------------------------------- > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace.part.0 (arch/arm64/kernel/stacktrace.c:186) > show_stack (arch/arm64/kernel/stacktrace.c:193) > dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4)) > dump_stack (lib/dump_stack.c:114) > print_circle (./arch/arm64/include/asm/atomic_ll_sc.h:112 ./arch/arm64/include/asm/atomic.h:30 ./include/linux/atomic/atomic-arch-fallback.h:511 ./include/linux/atomic/atomic-instrumented.h:258 kernel/dependency/dept.c:140 kernel/dependency/dept.c:748) > cb_check_dl (kernel/dependency/dept.c:1083 kernel/dependency/dept.c:1064) > bfs (kernel/dependency/dept.c:833) > add_dep (kernel/dependency/dept.c:1409) > do_event (kernel/dependency/dept.c:175 kernel/dependency/dept.c:1644) > dept_event (kernel/dependency/dept.c:2376 (discriminator 2)) > complete (kernel/sched/completion.c:33 (discriminator 4)) > kthread_complete_and_exit (kernel/kthread.c:327) > kunit_try_catch_throw (lib/kunit/try-catch.c:18) > kthread (kernel/kthread.c:379) > ret_from_fork (arch/arm64/kernel/entry.S:757) > > -- > Thank you, You are awesome! > Hyeonggon :-) > > > https://lkml.org/lkml/2022/3/15/1277 > > (or https://github.com/lgebyungchulpark/linux-dept/commits/dept1.18_on_v5.17-rc7) > > > > Thank you very much! > > > > -- > > Byungchul > > > > > Both cases look similar. > > > > > > In what case DEPT says (unknown)? > > > I'm not sure we can properly debug this. > > > > > > =================================================== > > > DEPT: Circular dependency has been detected. > > > 5.17.0-rc1+ #3 Tainted: G W > > > --------------------------------------------------- > > > summary > > > --------------------------------------------------- > > > *** AA DEADLOCK *** > > > > > > context A > > > [S] (unknown)(&vfork:0) > > > [W] wait_for_completion_killable(&vfork:0) > > > [E] complete(&vfork:0) > > > > > > [S]: start of the event context > > > [W]: the wait blocked > > > [E]: the event not reachable > > > --------------------------------------------------- > > > context A's detail > > > --------------------------------------------------- > > > context A > > > [S] (unknown)(&vfork:0) > > > [W] wait_for_completion_killable(&vfork:0) > > > [E] complete(&vfork:0) > > > > > > [S] (unknown)(&vfork:0): > > > (N/A) > > > > > > [W] wait_for_completion_killable(&vfork:0): > > > [<ffffffc00802204c>] kernel_clone+0x25c/0x2b8 > > > stacktrace: > > > dept_wait+0x74/0x88 > > > wait_for_completion_killable+0x60/0xa0 > > > kernel_clone+0x25c/0x2b8 > > > __do_sys_clone+0x5c/0x74 > > > __arm64_sys_clone+0x18/0x20 > > > invoke_syscall.constprop.0+0x78/0xc4 > > > do_el0_svc+0x98/0xd0 > > > el0_svc+0x44/0xe4 > > > el0t_64_sync_handler+0xb0/0x12c > > > el0t_64_sync+0x158/0x15c > > > > > > [E] complete(&vfork:0): > > > [<ffffffc00801f49c>] mm_release+0x7c/0x90 > > > stacktrace: > > > dept_event+0xe0/0x100 > > > complete+0x48/0x98 > > > mm_release+0x7c/0x90 > > > exit_mm_release+0xc/0x14 > > > do_exit+0x1b4/0x81c > > > do_group_exit+0x30/0x9c > > > __wake_up_parent+0x0/0x24 > > > invoke_syscall.constprop.0+0x78/0xc4 > > > do_el0_svc+0x98/0xd0 > > > el0_svc+0x44/0xe4 > > > el0t_64_sync_handler+0xb0/0x12c > > > el0t_64_sync+0x158/0x15c > > > --------------------------------------------------- > > > information that might be helpful > > > --------------------------------------------------- > > > CPU: 6 PID: 229 Comm: start-stop-daem Tainted: G W 5.17.0-rc1+ #3 > > > Hardware name: linux,dummy-virt (DT) > > > Call trace: > > > dump_backtrace.part.0+0x9c/0xc4 > > > show_stack+0x14/0x28 > > > dump_stack_lvl+0x9c/0xcc > > > dump_stack+0x14/0x2c > > > print_circle+0x2d4/0x438 > > > cb_check_dl+0x44/0x70 > > > bfs+0x60/0x168 > > > add_dep+0x88/0x11c > > > do_event.constprop.0+0x19c/0x2c0 > > > dept_event+0xe0/0x100 > > > complete+0x48/0x98 > > > mm_release+0x7c/0x90 > > > exit_mm_release+0xc/0x14 > > > do_exit+0x1b4/0x81c > > > do_group_exit+0x30/0x9c > > > __wake_up_parent+0x0/0x24 > > > invoke_syscall.constprop.0+0x78/0xc4 > > > do_el0_svc+0x98/0xd0 > > > el0_svc+0x44/0xe4 > > > el0t_64_sync_handler+0xb0/0x12c > > > el0t_64_sync+0x158/0x15c > > > > > > > > > > > > > > > =================================================== > > > DEPT: Circular dependency has been detected. > > > 5.17.0-rc1+ #3 Tainted: G W > > > --------------------------------------------------- > > > summary > > > --------------------------------------------------- > > > *** AA DEADLOCK *** > > > > > > context A > > > [S] (unknown)(&try_completion:0) > > > [W] wait_for_completion_timeout(&try_completion:0) > > > [E] complete(&try_completion:0) > > > > > > [S]: start of the event context > > > [W]: the wait blocked > > > [E]: the event not reachable > > > --------------------------------------------------- > > > context A's detail > > > --------------------------------------------------- > > > context A > > > [S] (unknown)(&try_completion:0) > > > [W] wait_for_completion_timeout(&try_completion:0) > > > [E] complete(&try_completion:0) > > > > > > [S] (unknown)(&try_completion:0): > > > (N/A) > > > > > > [W] wait_for_completion_timeout(&try_completion:0): > > > [<ffffffc008166bf4>] kunit_try_catch_run+0xb4/0x160 > > > stacktrace: > > > dept_wait+0x74/0x88 > > > wait_for_completion_timeout+0x64/0xa0 > > > kunit_try_catch_run+0xb4/0x160 > > > kunit_test_try_catch_successful_try_no_catch+0x3c/0x98 > > > kunit_try_run_case+0x9c/0xa0 > > > kunit_generic_run_threadfn_adapter+0x1c/0x28 > > > kthread+0xd4/0xe4 > > > ret_from_fork+0x10/0x20 > > > > > > [E] complete(&try_completion:0): > > > [<ffffffc00803dce4>] kthread_complete_and_exit+0x18/0x20 > > > stacktrace: > > > dept_event+0xe0/0x100 > > > complete+0x48/0x98 > > > kthread_complete_and_exit+0x18/0x20 > > > kunit_try_catch_throw+0x0/0x1c > > > kthread+0xd4/0xe4 > > > ret_from_fork+0x10/0x20 > > > > > > --------------------------------------------------- > > > information that might be helpful > > > --------------------------------------------------- > > > CPU: 15 PID: 132 Comm: kunit_try_catch Tainted: G W 5.17.0-rc1+ #3 > > > Hardware name: linux,dummy-virt (DT) > > > Call trace: > > > dump_backtrace.part.0+0x9c/0xc4 > > > show_stack+0x14/0x28 > > > dump_stack_lvl+0x9c/0xcc > > > dump_stack+0x14/0x2c > > > print_circle+0x2d4/0x438 > > > cb_check_dl+0x44/0x70 > > > bfs+0x60/0x168 > > > add_dep+0x88/0x11c > > > do_event.constprop.0+0x19c/0x2c0 > > > dept_event+0xe0/0x100 > > > complete+0x48/0x98 > > > kthread_complete_and_exit+0x18/0x20 > > > kunit_try_catch_throw+0x0/0x1c > > > kthread+0xd4/0xe4 > > > ret_from_fork+0x10/0x20 > > > > > > > > > > Benifit: > > > > > > > > 0. Works with all lock primitives. > > > > 1. Works with wait_for_completion()/complete(). > > > > 2. Works with 'wait' on PG_locked. > > > > 3. Works with 'wait' on PG_writeback. > > > > 4. Works with swait/wakeup. > > > > 5. Works with waitqueue. > > > > 6. Multiple reports are allowed. > > > > 7. Deduplication control on multiple reports. > > > > 8. Withstand false positives thanks to 6. > > > > 9. Easy to tag any wait/event. > > > > > > > > Future work: > > > > > > [...] > > > > > > > -- > > > > 1.9.1 > > > > > > > > > > -- > > > Thank you, You are awesome! > > > Hyeonggon :-)
On Fri, Mar 18, 2022 at 04:51:29PM +0900, Byungchul Park wrote: > On Wed, Mar 16, 2022 at 09:30:02AM +0000, Hyeonggon Yoo wrote: > > On Wed, Mar 16, 2022 at 01:32:13PM +0900, Byungchul Park wrote: > > > On Sat, Mar 12, 2022 at 01:53:26AM +0000, Hyeonggon Yoo wrote: > > > > On Fri, Mar 04, 2022 at 04:06:19PM +0900, Byungchul Park wrote: > > > > > Hi Linus and folks, > > > > > > > > > > I've been developing a tool for detecting deadlock possibilities by > > > > > tracking wait/event rather than lock(?) acquisition order to try to > > > > > cover all synchonization machanisms. It's done on v5.17-rc1 tag. > > > > > > > > > > https://github.com/lgebyungchulpark/linux-dept/commits/dept1.14_on_v5.17-rc1 > > > > > > > > > > > > > Small feedback unrelated to thread: > > > > I'm not sure "Need to expand the ring buffer" is something to call > > > > WARN(). Is this stack trace useful for something? > > > > ======== > > > > > > > > Hello Byungchul. These are two warnings of DEPT on system. > > > > > > Hi Hyeonggon, > > > > > > Could you run scripts/decode_stacktrace.sh and share the result instead > > > of the raw format below if the reports still appear with PATCH v5? It'd > > > be appreciated (: > > > > > > > Hi Byungchul. > > > > on dept1.18_on_v5.17-rc7, the kernel_clone() warning has gone. > > There is one warning remaining on my system: > > > > It warns when running kunit-try-catch-test testcase. > > Hi Hyeonggon, > > I can reproduce it thanks to you. I will let you know on all works done. Hi Hyeonggon, All works wrt this issue have been done. I've just updated the same branch. https://github.com/lgebyungchulpark/linux-dept/commits/dept1.18_on_v5.17-rc7 This is just for your information. Thanks, Byungchul > > Thanks, > Byungchul > > > =================================================== > > DEPT: Circular dependency has been detected. > > 5.17.0-rc7+ #4 Not tainted > > --------------------------------------------------- > > summary > > --------------------------------------------------- > > *** AA DEADLOCK *** > > > > context A > > [S] (unknown)(&try_completion:0) > > [W] wait_for_completion_timeout(&try_completion:0) > > [E] complete(&try_completion:0) > > > > [S]: start of the event context > > [W]: the wait blocked > > [E]: the event not reachable > > --------------------------------------------------- > > context A's detail > > --------------------------------------------------- > > context A > > [S] (unknown)(&try_completion:0) > > [W] wait_for_completion_timeout(&try_completion:0) > > [E] complete(&try_completion:0) > > > > [S] (unknown)(&try_completion:0): > > (N/A) > > > > [W] wait_for_completion_timeout(&try_completion:0): > > kunit_try_catch_run (lib/kunit/try-catch.c:78 (discriminator 1)) > > stacktrace: > > dept_wait (kernel/dependency/dept.c:2149) > > wait_for_completion_timeout (kernel/sched/completion.c:119 (discriminator 4) kernel/sched/completion.c:165 (discriminator 4)) > > kunit_try_catch_run (lib/kunit/try-catch.c:78 (discriminator 1)) > > kunit_test_try_catch_successful_try_no_catch (lib/kunit/kunit-test.c:43) > > kunit_try_run_case (lib/kunit/test.c:333 lib/kunit/test.c:374) > > kunit_generic_run_threadfn_adapter (lib/kunit/try-catch.c:30) > > kthread (kernel/kthread.c:379) > > ret_from_fork (arch/arm64/kernel/entry.S:757) > > > > [E] complete(&try_completion:0): > > kthread_complete_and_exit (kernel/kthread.c:327) > > stacktrace: > > dept_event (kernel/dependency/dept.c:2376 (discriminator 2)) > > complete (kernel/sched/completion.c:33 (discriminator 4)) > > kthread_complete_and_exit (kernel/kthread.c:327) > > kunit_try_catch_throw (lib/kunit/try-catch.c:18) > > kthread (kernel/kthread.c:379) > > ret_from_fork (arch/arm64/kernel/entry.S:757) > > > > --------------------------------------------------- > > information that might be helpful > > --------------------------------------------------- > > Hardware name: linux,dummy-virt (DT) > > Call trace: > > dump_backtrace.part.0 (arch/arm64/kernel/stacktrace.c:186) > > show_stack (arch/arm64/kernel/stacktrace.c:193) > > dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4)) > > dump_stack (lib/dump_stack.c:114) > > print_circle (./arch/arm64/include/asm/atomic_ll_sc.h:112 ./arch/arm64/include/asm/atomic.h:30 ./include/linux/atomic/atomic-arch-fallback.h:511 ./include/linux/atomic/atomic-instrumented.h:258 kernel/dependency/dept.c:140 kernel/dependency/dept.c:748) > > cb_check_dl (kernel/dependency/dept.c:1083 kernel/dependency/dept.c:1064) > > bfs (kernel/dependency/dept.c:833) > > add_dep (kernel/dependency/dept.c:1409) > > do_event (kernel/dependency/dept.c:175 kernel/dependency/dept.c:1644) > > dept_event (kernel/dependency/dept.c:2376 (discriminator 2)) > > complete (kernel/sched/completion.c:33 (discriminator 4)) > > kthread_complete_and_exit (kernel/kthread.c:327) > > kunit_try_catch_throw (lib/kunit/try-catch.c:18) > > kthread (kernel/kthread.c:379) > > ret_from_fork (arch/arm64/kernel/entry.S:757) > > > > -- > > Thank you, You are awesome! > > Hyeonggon :-) > > > > > https://lkml.org/lkml/2022/3/15/1277 > > > (or https://github.com/lgebyungchulpark/linux-dept/commits/dept1.18_on_v5.17-rc7) > > > > > > Thank you very much! > > > > > > -- > > > Byungchul > > > > > > > Both cases look similar. > > > > > > > > In what case DEPT says (unknown)? > > > > I'm not sure we can properly debug this. > > > > > > > > =================================================== > > > > DEPT: Circular dependency has been detected. > > > > 5.17.0-rc1+ #3 Tainted: G W > > > > --------------------------------------------------- > > > > summary > > > > --------------------------------------------------- > > > > *** AA DEADLOCK *** > > > > > > > > context A > > > > [S] (unknown)(&vfork:0) > > > > [W] wait_for_completion_killable(&vfork:0) > > > > [E] complete(&vfork:0) > > > > > > > > [S]: start of the event context > > > > [W]: the wait blocked > > > > [E]: the event not reachable > > > > --------------------------------------------------- > > > > context A's detail > > > > --------------------------------------------------- > > > > context A > > > > [S] (unknown)(&vfork:0) > > > > [W] wait_for_completion_killable(&vfork:0) > > > > [E] complete(&vfork:0) > > > > > > > > [S] (unknown)(&vfork:0): > > > > (N/A) > > > > > > > > [W] wait_for_completion_killable(&vfork:0): > > > > [<ffffffc00802204c>] kernel_clone+0x25c/0x2b8 > > > > stacktrace: > > > > dept_wait+0x74/0x88 > > > > wait_for_completion_killable+0x60/0xa0 > > > > kernel_clone+0x25c/0x2b8 > > > > __do_sys_clone+0x5c/0x74 > > > > __arm64_sys_clone+0x18/0x20 > > > > invoke_syscall.constprop.0+0x78/0xc4 > > > > do_el0_svc+0x98/0xd0 > > > > el0_svc+0x44/0xe4 > > > > el0t_64_sync_handler+0xb0/0x12c > > > > el0t_64_sync+0x158/0x15c > > > > > > > > [E] complete(&vfork:0): > > > > [<ffffffc00801f49c>] mm_release+0x7c/0x90 > > > > stacktrace: > > > > dept_event+0xe0/0x100 > > > > complete+0x48/0x98 > > > > mm_release+0x7c/0x90 > > > > exit_mm_release+0xc/0x14 > > > > do_exit+0x1b4/0x81c > > > > do_group_exit+0x30/0x9c > > > > __wake_up_parent+0x0/0x24 > > > > invoke_syscall.constprop.0+0x78/0xc4 > > > > do_el0_svc+0x98/0xd0 > > > > el0_svc+0x44/0xe4 > > > > el0t_64_sync_handler+0xb0/0x12c > > > > el0t_64_sync+0x158/0x15c > > > > --------------------------------------------------- > > > > information that might be helpful > > > > --------------------------------------------------- > > > > CPU: 6 PID: 229 Comm: start-stop-daem Tainted: G W 5.17.0-rc1+ #3 > > > > Hardware name: linux,dummy-virt (DT) > > > > Call trace: > > > > dump_backtrace.part.0+0x9c/0xc4 > > > > show_stack+0x14/0x28 > > > > dump_stack_lvl+0x9c/0xcc > > > > dump_stack+0x14/0x2c > > > > print_circle+0x2d4/0x438 > > > > cb_check_dl+0x44/0x70 > > > > bfs+0x60/0x168 > > > > add_dep+0x88/0x11c > > > > do_event.constprop.0+0x19c/0x2c0 > > > > dept_event+0xe0/0x100 > > > > complete+0x48/0x98 > > > > mm_release+0x7c/0x90 > > > > exit_mm_release+0xc/0x14 > > > > do_exit+0x1b4/0x81c > > > > do_group_exit+0x30/0x9c > > > > __wake_up_parent+0x0/0x24 > > > > invoke_syscall.constprop.0+0x78/0xc4 > > > > do_el0_svc+0x98/0xd0 > > > > el0_svc+0x44/0xe4 > > > > el0t_64_sync_handler+0xb0/0x12c > > > > el0t_64_sync+0x158/0x15c > > > > > > > > > > > > > > > > > > > > =================================================== > > > > DEPT: Circular dependency has been detected. > > > > 5.17.0-rc1+ #3 Tainted: G W > > > > --------------------------------------------------- > > > > summary > > > > --------------------------------------------------- > > > > *** AA DEADLOCK *** > > > > > > > > context A > > > > [S] (unknown)(&try_completion:0) > > > > [W] wait_for_completion_timeout(&try_completion:0) > > > > [E] complete(&try_completion:0) > > > > > > > > [S]: start of the event context > > > > [W]: the wait blocked > > > > [E]: the event not reachable > > > > --------------------------------------------------- > > > > context A's detail > > > > --------------------------------------------------- > > > > context A > > > > [S] (unknown)(&try_completion:0) > > > > [W] wait_for_completion_timeout(&try_completion:0) > > > > [E] complete(&try_completion:0) > > > > > > > > [S] (unknown)(&try_completion:0): > > > > (N/A) > > > > > > > > [W] wait_for_completion_timeout(&try_completion:0): > > > > [<ffffffc008166bf4>] kunit_try_catch_run+0xb4/0x160 > > > > stacktrace: > > > > dept_wait+0x74/0x88 > > > > wait_for_completion_timeout+0x64/0xa0 > > > > kunit_try_catch_run+0xb4/0x160 > > > > kunit_test_try_catch_successful_try_no_catch+0x3c/0x98 > > > > kunit_try_run_case+0x9c/0xa0 > > > > kunit_generic_run_threadfn_adapter+0x1c/0x28 > > > > kthread+0xd4/0xe4 > > > > ret_from_fork+0x10/0x20 > > > > > > > > [E] complete(&try_completion:0): > > > > [<ffffffc00803dce4>] kthread_complete_and_exit+0x18/0x20 > > > > stacktrace: > > > > dept_event+0xe0/0x100 > > > > complete+0x48/0x98 > > > > kthread_complete_and_exit+0x18/0x20 > > > > kunit_try_catch_throw+0x0/0x1c > > > > kthread+0xd4/0xe4 > > > > ret_from_fork+0x10/0x20 > > > > > > > > --------------------------------------------------- > > > > information that might be helpful > > > > --------------------------------------------------- > > > > CPU: 15 PID: 132 Comm: kunit_try_catch Tainted: G W 5.17.0-rc1+ #3 > > > > Hardware name: linux,dummy-virt (DT) > > > > Call trace: > > > > dump_backtrace.part.0+0x9c/0xc4 > > > > show_stack+0x14/0x28 > > > > dump_stack_lvl+0x9c/0xcc > > > > dump_stack+0x14/0x2c > > > > print_circle+0x2d4/0x438 > > > > cb_check_dl+0x44/0x70 > > > > bfs+0x60/0x168 > > > > add_dep+0x88/0x11c > > > > do_event.constprop.0+0x19c/0x2c0 > > > > dept_event+0xe0/0x100 > > > > complete+0x48/0x98 > > > > kthread_complete_and_exit+0x18/0x20 > > > > kunit_try_catch_throw+0x0/0x1c > > > > kthread+0xd4/0xe4 > > > > ret_from_fork+0x10/0x20 > > > > > > > > > > > > > Benifit: > > > > > > > > > > 0. Works with all lock primitives. > > > > > 1. Works with wait_for_completion()/complete(). > > > > > 2. Works with 'wait' on PG_locked. > > > > > 3. Works with 'wait' on PG_writeback. > > > > > 4. Works with swait/wakeup. > > > > > 5. Works with waitqueue. > > > > > 6. Multiple reports are allowed. > > > > > 7. Deduplication control on multiple reports. > > > > > 8. Withstand false positives thanks to 6. > > > > > 9. Easy to tag any wait/event. > > > > > > > > > > Future work: > > > > > > > > [...] > > > > > > > > > -- > > > > > 1.9.1 > > > > > > > > > > > > > -- > > > > Thank you, You are awesome! > > > > Hyeonggon :-)
Hi Linus and folks, I've been developing a tool for detecting deadlock possibilities by tracking wait/event rather than lock(?) acquisition order to try to cover all synchonization machanisms. It's done on v5.17-rc1 tag. https://github.com/lgebyungchulpark/linux-dept/commits/dept1.14_on_v5.17-rc1 Benifit: 0. Works with all lock primitives. 1. Works with wait_for_completion()/complete(). 2. Works with 'wait' on PG_locked. 3. Works with 'wait' on PG_writeback. 4. Works with swait/wakeup. 5. Works with waitqueue. 6. Multiple reports are allowed. 7. Deduplication control on multiple reports. 8. Withstand false positives thanks to 6. 9. Easy to tag any wait/event. Future work: 0. To make it more stable. 1. To separates Dept from Lockdep. 2. To improves performance in terms of time and space. 3. To use Dept as a dependency engine for Lockdep. 4. To add any missing tags of wait/event in the kernel. 5. To deduplicate stack trace. How to interpret reports: 1. E(event) in each context cannot be triggered because of the W(wait) that cannot be woken. 2. The stack trace helping find the problematic code is located in each conext's detail. Thanks, Byungchul --- Changes from v3: 1. Dept shouldn't create dependencies between different depths of a class that were indicated by *_lock_nested(). Dept normally doesn't but it does once another lock class comes in. So fixed it. (feedback from Hyeonggon) 2. Dept considered a wait as a real wait once getting to __schedule() even if it has been set to TASK_RUNNING by wake up sources in advance. Fixed it so that Dept doesn't consider the case as a real wait. (feedback from Jan Kara) 3. Stop tracking dependencies with a map once the event associated with the map has been handled. Dept will start to work with the map again, on the next sleep. Changes from v2: 1. Disable Dept on bit_wait_table[] in sched/wait_bit.c reporting a lot of false positives, which is my fault. Wait/event for bit_wait_table[] should've been tagged in a higher layer for better work, which is a future work. (feedback from Jan Kara) 2. Disable Dept on crypto_larval's completion to prevent a false positive. Changes from v1: 1. Fix coding style and typo. (feedback from Steven) 2. Distinguish each work context from another in workqueue. 3. Skip checking lock acquisition with nest_lock, which is about correct lock usage that should be checked by Lockdep. Changes from RFC: 1. Prevent adding a wait tag at prepare_to_wait() but __schedule(). (feedback from Linus and Matthew) 2. Use try version at lockdep_acquire_cpus_lock() annotation. 3. Distinguish each syscall context from another. Byungchul Park (24): llist: Move llist_{head,node} definition to types.h dept: Implement Dept(Dependency Tracker) dept: Embed Dept data in Lockdep dept: Add a API for skipping dependency check temporarily dept: Apply Dept to spinlock dept: Apply Dept to mutex families dept: Apply Dept to rwlock dept: Apply Dept to wait_for_completion()/complete() dept: Apply Dept to seqlock dept: Apply Dept to rwsem dept: Add proc knobs to show stats and dependency graph dept: Introduce split map concept and new APIs for them dept: Apply Dept to wait/event of PG_{locked,writeback} dept: Apply SDT to swait dept: Apply SDT to wait(waitqueue) locking/lockdep, cpu/hotplus: Use a weaker annotation in AP thread dept: Distinguish each syscall context from another dept: Distinguish each work from another dept: Disable Dept within the wait_bit layer by default dept: Add nocheck version of init_completion() dept: Disable Dept on struct crypto_larval's completion for now dept: Don't create dependencies between different depths in any case dept: Let it work with real sleeps in __schedule() dept: Disable Dept on that map once it's been handled until next turn crypto/api.c | 7 +- include/linux/completion.h | 50 +- include/linux/dept.h | 535 +++++++ include/linux/dept_page.h | 78 ++ include/linux/dept_sdt.h | 62 + include/linux/hardirq.h | 3 + include/linux/irqflags.h | 33 +- include/linux/llist.h | 8 - include/linux/lockdep.h | 158 ++- include/linux/lockdep_types.h | 3 + include/linux/mutex.h | 33 + include/linux/page-flags.h | 45 +- include/linux/pagemap.h | 7 +- include/linux/percpu-rwsem.h | 10 +- include/linux/rtmutex.h | 7 + include/linux/rwlock.h | 52 + include/linux/rwlock_api_smp.h | 8 +- include/linux/rwlock_types.h | 7 + include/linux/rwsem.h | 33 + include/linux/sched.h | 7 + include/linux/seqlock.h | 59 +- include/linux/spinlock.h | 26 + include/linux/spinlock_types_raw.h | 13 + include/linux/swait.h | 4 + include/linux/types.h | 8 + include/linux/wait.h | 6 +- init/init_task.c | 2 + init/main.c | 4 + kernel/Makefile | 1 + kernel/cpu.c | 2 +- kernel/dependency/Makefile | 4 + kernel/dependency/dept.c | 2716 ++++++++++++++++++++++++++++++++++++ kernel/dependency/dept_hash.h | 10 + kernel/dependency/dept_internal.h | 26 + kernel/dependency/dept_object.h | 13 + kernel/dependency/dept_proc.c | 92 ++ kernel/entry/common.c | 3 + kernel/exit.c | 1 + kernel/fork.c | 2 + kernel/locking/lockdep.c | 12 +- kernel/module.c | 2 + kernel/sched/completion.c | 12 +- kernel/sched/core.c | 8 + kernel/sched/swait.c | 10 + kernel/sched/wait.c | 16 + kernel/sched/wait_bit.c | 5 +- kernel/softirq.c | 6 +- kernel/trace/trace_preemptirq.c | 19 +- kernel/workqueue.c | 3 + lib/Kconfig.debug | 21 + mm/filemap.c | 68 + mm/page_ext.c | 5 + 52 files changed, 4266 insertions(+), 59 deletions(-) create mode 100644 include/linux/dept.h create mode 100644 include/linux/dept_page.h create mode 100644 include/linux/dept_sdt.h create mode 100644 kernel/dependency/Makefile create mode 100644 kernel/dependency/dept.c create mode 100644 kernel/dependency/dept_hash.h create mode 100644 kernel/dependency/dept_internal.h create mode 100644 kernel/dependency/dept_object.h create mode 100644 kernel/dependency/dept_proc.c