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Groups > linux.kernel > #1607635
| From | Johannes Berg <johannes@sipsolutions.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: deadlock in synchronize_srcu() in debugfs? |
| Date | 2017-03-23 16:40 +0100 |
| Message-ID | <tod0f-4a5-35@gated-at.bofh.it> (permalink) |
| References | <tocnv-3Ak-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, 2017-03-23 at 15:54 +0100, Johannes Berg wrote: > Before I go hunting - has anyone seen a deadlock in > synchronize_srcu() in debugfs_remove() before? Isn't it possible for the following to happen? CPU1 CPU2 mutex_lock(&M); full_proxy_xyz(); srcu_read_lock(&debugfs_srcu); real_fops->xyz(); mutex_lock(&M); debugfs_remove(F); synchronize_srcu(&debugfs_srcu); -> deadlock? I'm not convinced that this is the scenario I'm looking at, since then it seems I should see the mutex_lock(&M) on CPU 2 with a backtrace pointing to a full_proxy and the debugfs operation I recognize, but lots of debugfs files acquire locks and it seems likely that it's not always removed without holding those locks? Am I missing something? I'll see if I can add lockdep annotations. johannes
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deadlock in synchronize_srcu() in debugfs? Johannes Berg <johannes@sipsolutions.net> - 2017-03-23 16:00 +0100
Re: deadlock in synchronize_srcu() in debugfs? Nicolai Stange <nicstange@gmail.com> - 2017-03-23 16:40 +0100
Re: deadlock in synchronize_srcu() in debugfs? Johannes Berg <johannes@sipsolutions.net> - 2017-03-23 16:50 +0100
Re: deadlock in synchronize_srcu() in debugfs? Johannes Berg <johannes@sipsolutions.net> - 2017-03-27 14:00 +0200
Re: deadlock in synchronize_srcu() in debugfs? "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-03-23 16:40 +0100
Re: deadlock in synchronize_srcu() in debugfs? Johannes Berg <johannes@sipsolutions.net> - 2017-03-23 16:50 +0100
Re: deadlock in synchronize_srcu() in debugfs? Johannes Berg <johannes@sipsolutions.net> - 2017-03-23 16:40 +0100
Re: deadlock in synchronize_srcu() in debugfs? Johannes Berg <johannes@sipsolutions.net> - 2017-03-24 10:00 +0100
Re: deadlock in synchronize_srcu() in debugfs? Johannes Berg <johannes@sipsolutions.net> - 2017-03-24 10:30 +0100
Re: deadlock in synchronize_srcu() in debugfs? "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-03-24 18:50 +0100
Re: deadlock in synchronize_srcu() in debugfs? Johannes Berg <johannes@sipsolutions.net> - 2017-03-24 20:00 +0100
Re: deadlock in synchronize_srcu() in debugfs? "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-03-24 20:40 +0100
Re: deadlock in synchronize_srcu() in debugfs? "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-03-24 21:30 +0100
Re: deadlock in synchronize_srcu() in debugfs? Johannes Berg <johannes@sipsolutions.net> - 2017-03-27 13:20 +0200
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