Date: Tue, 12 Dec 2017 19:30:45 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-fs@FreeBSD.org Subject: [Bug 224292] processes are hanging in state ufs / possible deadlock in file system Message-ID: <bug-224292-3630-mkla7BngOJ@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-224292-3630@https.bugs.freebsd.org/bugzilla/> References: <bug-224292-3630@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D224292 Kirk McKusick <mckusick@FreeBSD.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |mckusick@FreeBSD.org --- Comment #2 from Kirk McKusick <mckusick@FreeBSD.org> --- It is possible that this patch will fix this problem: r326657 | kib | 2017-12-07 01:05:34 -0800 (Thu, 07 Dec 2017) | 15 lines Fix livelock in ufsdirhash_create(). When more than one thread enters ufsdirhash_create() for the same directory and the inode dirhash is instantiated, but the dirhash' hash is not, all of them lock the dirhash shared and then try to upgrade. Since there are several threads owning the lock shared, upgrade fails and the same attempt is repeated, ad infinitum. To break the lockstep, lock the dirhash in exclusive mode after the failed try-upgrade. Reported and tested by: pho Sponsored by: Mellanox Technologies MFC after: 1 week It is also known that dirhash tuning as described by Wolfram Schneider above significantly mitigates this problem. --=20 You are receiving this mail because: You are the assignee for the bug.=
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