From: Byungchul Park <byungchul.park@lge.com> To: tj@kernel.org Cc: torvalds@linux-foundation.org, damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, linux-kernel@vger.kernel.org, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, chris@chris-wilson.co.uk, duyuyang@gmail.com, johannes.berg@intel.com, tytso@mit.edu, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, gregkh@linuxfoundation.org, kernel-team@lge.com, linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org, minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com, sj@kernel.org, jglisse@redhat.com, dennis@kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, vbabka@suse.cz, ngupta@vflare.org, linux-block@vger.kernel.org, paolo.valente@linaro.org, josef@toxicpanda.com, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, jack@suse.cz, jack@suse.com, jlayton@kernel.org, dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org, dri-devel@lists.freedesktop.org, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com, 42.hyeyoo@gmail.com, mcgrof@kernel.org, holt@sgi.com Subject: Re: [REPORT] syscall reboot + umh + firmware fallback Date: Thu, 12 May 2022 20:18:24 +0900 [thread overview] Message-ID: <1652354304-17492-1-git-send-email-byungchul.park@lge.com> (raw) In-Reply-To: <YnzQHWASAxsGL9HW@slm.duckdns.org> Tejun wrote: > Hello, Hello, > I'm not sure I'm reading it correctly but it looks like "process B" column I think you're interpreting the report correctly. > is superflous given that it's waiting on the same lock to do the same thing > that A is already doing (besides, you can't really halt the machine twice). Indeed! I've been in a daze. I thought kernel_halt() can be called twice by two different purposes. Sorry for the noise. > What it's reporting seems to be ABBA deadlock between A waiting on > umhelper_sem and C waiting on fw_st->completion. The report seems spurious: > > 1. wait_for_completion_killable_timeout() doesn't need someone to wake it up > to make forward progress because it will unstick itself after timeout > expires. I have a question about this one. Yes, it would never been stuck thanks to timeout. However, IIUC, timeouts are not supposed to expire in normal cases. So I thought a timeout expiration means not a normal case so need to inform it in terms of dependency so as to prevent further expiraton. That's why I have been trying to track even timeout'ed APIs. Do you think DEPT shouldn't track timeout APIs? If I was wrong, I shouldn't track the timeout APIs any more. > 2. complete_all() from __fw_load_abort() isn't the only source of wakeup. > The fw loader can be, and mainly should be, woken up by firmware loading > actually completing instead of being aborted. This is the point I'd like to ask. In normal cases, fw_load_done() might happen, of course, if the loading gets completed. However, I was wondering if the kernel ensures either fw_load_done() or fw_load_abort() to be called by *another* context while kernel_halt(). > Thanks. Thank you very much! Byungchul > > -- > tejun >
WARNING: multiple messages have this Message-ID (diff)
From: Byungchul Park <byungchul.park@lge.com> To: tj@kernel.org Cc: hamohammed.sa@gmail.com, jack@suse.cz, peterz@infradead.org, daniel.vetter@ffwll.ch, amir73il@gmail.com, david@fromorbit.com, dri-devel@lists.freedesktop.org, chris@chris-wilson.co.uk, linux-mm@kvack.org, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, joel@joelfernandes.org, 42.hyeyoo@gmail.com, cl@linux.com, will@kernel.org, duyuyang@gmail.com, sashal@kernel.org, paolo.valente@linaro.org, damien.lemoal@opensource.wdc.com, willy@infradead.org, hch@infradead.org, mingo@redhat.com, djwong@kernel.org, vdavydov.dev@gmail.com, rientjes@google.com, dennis@kernel.org, linux-ext4@vger.kernel.org, ngupta@vflare.org, johannes.berg@intel.com, jack@suse.com, dan.j.williams@intel.com, josef@toxicpanda.com, rostedt@goodmis.org, linux-block@vger.kernel.org, jglisse@redhat.com, viro@zeniv.linux.org.uk, tglx@linutronix.de, mhocko@kernel.org, vbabka@suse.cz, melissa.srw@gmail.com, sj@kernel.org, tytso@mit.edu, rodrigosiqueiramelo@gmail.com, kernel-team@lge.com, gregkh@linuxfoundation.org, jlayton@kernel.org, linux-kernel@vger.kernel.org, penberg@kernel.org, minchan@kernel.org, mcgrof@kernel.org, holt@sgi.com, hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, torvalds@linux-foundation.org Subject: Re: [REPORT] syscall reboot + umh + firmware fallback Date: Thu, 12 May 2022 20:18:24 +0900 [thread overview] Message-ID: <1652354304-17492-1-git-send-email-byungchul.park@lge.com> (raw) In-Reply-To: <YnzQHWASAxsGL9HW@slm.duckdns.org> Tejun wrote: > Hello, Hello, > I'm not sure I'm reading it correctly but it looks like "process B" column I think you're interpreting the report correctly. > is superflous given that it's waiting on the same lock to do the same thing > that A is already doing (besides, you can't really halt the machine twice). Indeed! I've been in a daze. I thought kernel_halt() can be called twice by two different purposes. Sorry for the noise. > What it's reporting seems to be ABBA deadlock between A waiting on > umhelper_sem and C waiting on fw_st->completion. The report seems spurious: > > 1. wait_for_completion_killable_timeout() doesn't need someone to wake it up > to make forward progress because it will unstick itself after timeout > expires. I have a question about this one. Yes, it would never been stuck thanks to timeout. However, IIUC, timeouts are not supposed to expire in normal cases. So I thought a timeout expiration means not a normal case so need to inform it in terms of dependency so as to prevent further expiraton. That's why I have been trying to track even timeout'ed APIs. Do you think DEPT shouldn't track timeout APIs? If I was wrong, I shouldn't track the timeout APIs any more. > 2. complete_all() from __fw_load_abort() isn't the only source of wakeup. > The fw loader can be, and mainly should be, woken up by firmware loading > actually completing instead of being aborted. This is the point I'd like to ask. In normal cases, fw_load_done() might happen, of course, if the loading gets completed. However, I was wondering if the kernel ensures either fw_load_done() or fw_load_abort() to be called by *another* context while kernel_halt(). > Thanks. Thank you very much! Byungchul > > -- > tejun >
next prev parent reply other threads:[~2022-05-12 11:22 UTC|newest] Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-05-04 8:17 [PATCH RFC v6 00/21] DEPT(Dependency Tracker) Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 01/21] llist: Move llist_{head,node} definition to types.h Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 01/21] llist: Move llist_{head, node} " Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 02/21] dept: Implement Dept(Dependency Tracker) Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 13:29 ` kernel test robot 2022-05-21 3:24 ` Hyeonggon Yoo 2022-05-21 3:24 ` Hyeonggon Yoo 2022-05-04 8:17 ` [PATCH RFC v6 03/21] dept: Apply Dept to spinlock Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 04/21] dept: Apply Dept to mutex families Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 05/21] dept: Apply Dept to rwlock Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 06/21] dept: Apply Dept to wait_for_completion()/complete() Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 07/21] dept: Apply Dept to seqlock Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-21 5:25 ` Hyeonggon Yoo 2022-05-21 5:25 ` Hyeonggon Yoo 2022-05-24 6:00 ` Byungchul Park 2022-05-24 6:00 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 08/21] dept: Apply Dept to rwsem Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 09/21] dept: Add proc knobs to show stats and dependency graph Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 10/21] dept: Introduce split map concept and new APIs for them Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 11/21] dept: Apply Dept to wait/event of PG_{locked,writeback} Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 11/21] dept: Apply Dept to wait/event of PG_{locked, writeback} Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 12/21] dept: Apply SDT to swait Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 13/21] dept: Apply SDT to wait(waitqueue) Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 14/21] locking/lockdep, cpu/hotplus: Use a weaker annotation in AP thread Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 15/21] dept: Distinguish each syscall context from another Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 16/21] dept: Distinguish each work " Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 11:23 ` Sergey Shtylyov 2022-05-04 11:23 ` Sergey Shtylyov 2022-05-04 8:17 ` [PATCH RFC v6 17/21] dept: Disable Dept within the wait_bit layer by default Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 18/21] dept: Disable Dept on struct crypto_larval's completion for now Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 19/21] dept: Differentiate onstack maps from others of different tasks in class Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 20/21] dept: Do not add dependencies between events within scheduler and sleeps Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 8:17 ` [PATCH RFC v6 21/21] dept: Unstage wait when tagging a normal sleep wait Byungchul Park 2022-05-04 8:17 ` Byungchul Park 2022-05-04 18:17 ` [PATCH RFC v6 00/21] DEPT(Dependency Tracker) Linus Torvalds 2022-05-04 18:17 ` Linus Torvalds 2022-05-06 0:11 ` Byungchul Park 2022-05-06 0:11 ` Byungchul Park 2022-05-07 7:20 ` Hyeonggon Yoo 2022-05-07 7:20 ` Hyeonggon Yoo 2022-05-09 0:16 ` Byungchul Park 2022-05-09 0:16 ` Byungchul Park 2022-05-09 20:47 ` Steven Rostedt 2022-05-09 20:47 ` Steven Rostedt 2022-05-09 23:38 ` Byungchul Park 2022-05-09 23:38 ` Byungchul Park 2022-05-10 14:12 ` Steven Rostedt 2022-05-10 14:12 ` Steven Rostedt 2022-05-10 23:26 ` Byungchul Park 2022-05-10 23:26 ` Byungchul Park 2022-05-10 11:18 ` Hyeonggon Yoo 2022-05-10 11:18 ` Hyeonggon Yoo 2022-05-10 23:39 ` Byungchul Park 2022-05-10 23:39 ` Byungchul Park 2022-05-11 10:04 ` Hyeonggon Yoo 2022-05-11 10:04 ` Hyeonggon Yoo 2022-05-19 10:11 ` Catalin Marinas 2022-05-19 10:11 ` Catalin Marinas 2022-05-23 2:43 ` Byungchul Park 2022-05-23 2:43 ` Byungchul Park 2022-05-09 1:22 ` Byungchul Park 2022-05-09 1:22 ` Byungchul Park 2022-05-09 21:05 ` Theodore Ts'o 2022-05-09 21:05 ` Theodore Ts'o 2022-05-09 22:28 ` Theodore Ts'o 2022-05-09 22:28 ` Theodore Ts'o 2022-05-10 0:32 ` Byungchul Park 2022-05-10 0:32 ` Byungchul Park 2022-05-10 1:32 ` Theodore Ts'o 2022-05-10 1:32 ` Theodore Ts'o 2022-05-10 5:37 ` Byungchul Park 2022-05-10 5:37 ` Byungchul Park 2022-05-11 1:16 ` Byungchul Park 2022-05-11 1:16 ` Byungchul Park 2022-05-12 5:25 ` [REPORT] syscall reboot + umh + firmware fallback Byungchul Park 2022-05-12 5:25 ` Byungchul Park 2022-05-12 9:15 ` Tejun Heo 2022-05-12 9:15 ` Tejun Heo 2022-05-12 11:18 ` Byungchul Park [this message] 2022-05-12 11:18 ` Byungchul Park 2022-05-12 13:56 ` Theodore Ts'o 2022-05-12 13:56 ` Theodore Ts'o 2022-05-23 1:10 ` Byungchul Park 2022-05-23 1:10 ` Byungchul Park 2022-05-12 16:41 ` Tejun Heo 2022-05-12 16:41 ` Tejun Heo
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