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From: Dave Jones <davej@redhat.com>
To: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: shmem_getpage_gfp VM_BUG_ON triggered. [3.7rc2]
Date: Thu, 1 Nov 2012 19:20:30 -0400	[thread overview]
Message-ID: <20121101232030.GA25519@redhat.com> (raw)
In-Reply-To: <alpine.LNX.2.00.1211011546090.19377@eggly.anvils>

On Thu, Nov 01, 2012 at 04:03:40PM -0700, Hugh Dickins wrote:
 > > I just noticed we had a user report hitting this same warning, but
 > > with a different trace..
 > > 
 > > : [<ffffffff8105b84f>] warn_slowpath_common+0x7f/0xc0
 > > : [<ffffffff8105b8aa>] warn_slowpath_null+0x1a/0x20
 > > : [<ffffffff81143c73>] shmem_getpage_gfp+0x7f3/0x830
 > > : [<ffffffff81158c9d>] ? vma_adjust+0x3ed/0x620
 > > : [<ffffffff81143f02>] shmem_file_aio_read+0x1f2/0x380
 > > : [<ffffffff8118e487>] do_sync_read+0xa7/0xe0
 > > : [<ffffffff8118eda9>] vfs_read+0xa9/0x180
 > > : [<ffffffff8118eeca>] sys_read+0x4a/0x90
 > > : [<ffffffff816226e9>] system_call_fastpath+0x16/0x1b
 > 
 > Equally explicable by Hannes's hypothesis;
 > but useful supporting evidence, thank you.
 > 
 > Except... earlier in the thread you explained how you hacked
 > #define VM_BUG_ON(cond) WARN_ON(cond)
 > to get this to come out as a warning instead of a bug,
 > and now it looks as if "a user" has here done the same.
 > 
 > Which is very much a user's right, of course; but does
 > make me wonder whether that user might actually be davej ;)

indirectly. I made the same change in the Fedora kernel a while ago
to test a hypothesis that we weren't getting any VM_BUG_ON reports.

	Dave

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  reply	other threads:[~2012-11-01 23:20 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-25  2:37 shmem_getpage_gfp VM_BUG_ON triggered. [3.7rc2] Dave Jones
2012-10-25  4:36 ` Hugh Dickins
2012-10-25  4:50   ` Ni zhan Chen
2012-10-25  6:59     ` Hugh Dickins
2012-10-25  9:53       ` Ni zhan Chen
2012-10-25 10:21       ` Ni zhan Chen
2012-10-25 21:27         ` Hugh Dickins
2012-10-26  1:48           ` Ni zhan Chen
2012-10-25 11:14   ` Dave Jones
2012-10-25 21:28     ` Hugh Dickins
2012-10-25 20:52   ` Johannes Weiner
2012-10-25 21:48     ` Hugh Dickins
2012-10-26  2:15       ` Ni zhan Chen
2012-11-01 19:10   ` Dave Jones
2012-11-01 23:03     ` Hugh Dickins
2012-11-01 23:20       ` Dave Jones [this message]
2012-11-01 23:48         ` Hugh Dickins
2012-11-02  1:43           ` Dave Jones
2012-11-02 23:26             ` Hugh Dickins
2012-11-06  1:32               ` [PATCH] tmpfs: fix shmem_getpage_gfp VM_BUG_ON Hugh Dickins
2012-11-06 13:54                 ` Dave Jones
2012-11-06 23:48                   ` Hugh Dickins
2012-11-07 22:38                     ` Dave Jones
2012-11-14  1:36                       ` [PATCH] tmpfs: fix shmem_getpage_gfp VM_BUG_ON fix Hugh Dickins
2012-11-14  3:07                     ` [PATCH] tmpfs: fix shmem_getpage_gfp VM_BUG_ON Jaegeuk Hanse
2012-11-14  3:50                       ` Hugh Dickins
2012-11-14  6:14                         ` Dave Jones
2012-11-14 10:06                           ` Hugh Dickins
2012-11-15  7:39                         ` Jaegeuk Hanse
2012-11-15 19:56                           ` Hugh Dickins
2012-11-16  0:40                             ` Jaegeuk Hanse
2012-11-16  9:34                             ` Jaegeuk Hanse
2012-11-17  4:48                               ` Hugh Dickins
2012-11-18  0:57                                 ` Jaegeuk Hanse
2012-11-18  1:48                                 ` Jaegeuk Hanse

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