[3.8.y.z extended stable] Patch "jffs2: avoid soft-lockup in jffs2_reserve_space_gc()" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Thu Apr 17 23:29:58 UTC 2014
This is a note to let you know that I have just added a patch titled
jffs2: avoid soft-lockup in jffs2_reserve_space_gc()
to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue
This patch is scheduled to be released in version 3.8.13.22.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From b36d5e182d0dc09391a939b4b8f1188a6c099f31 Mon Sep 17 00:00:00 2001
From: Li Zefan <lizefan at huawei.com>
Date: Wed, 12 Feb 2014 12:44:56 -0800
Subject: jffs2: avoid soft-lockup in jffs2_reserve_space_gc()
commit 13b546d96207c131eeae15dc7b26c6e7d0f1cad7 upstream.
We triggered soft-lockup under stress test on 2.6.34 kernel.
BUG: soft lockup - CPU#1 stuck for 60009ms! [lockf2.test:14488]
...
[<bf09a4d4>] (jffs2_do_reserve_space+0x420/0x440 [jffs2])
[<bf09a528>] (jffs2_reserve_space_gc+0x34/0x78 [jffs2])
[<bf0a1350>] (jffs2_garbage_collect_dnode.isra.3+0x264/0x478 [jffs2])
[<bf0a2078>] (jffs2_garbage_collect_pass+0x9c0/0xe4c [jffs2])
[<bf09a670>] (jffs2_reserve_space+0x104/0x2a8 [jffs2])
[<bf09dc48>] (jffs2_write_inode_range+0x5c/0x4d4 [jffs2])
[<bf097d8c>] (jffs2_write_end+0x198/0x2c0 [jffs2])
[<c00e00a4>] (generic_file_buffered_write+0x158/0x200)
[<c00e14f4>] (__generic_file_aio_write+0x3a4/0x414)
[<c00e15c0>] (generic_file_aio_write+0x5c/0xbc)
[<c012334c>] (do_sync_write+0x98/0xd4)
[<c0123a84>] (vfs_write+0xa8/0x150)
[<c0123d74>] (sys_write+0x3c/0xc0)]
Fix this by adding a cond_resched() in the while loop.
[akpm at linux-foundation.org: don't initialize `ret']
Signed-off-by: Li Zefan <lizefan at huawei.com>
Cc: David Woodhouse <dwmw2 at infradead.org>
Cc: Artem Bityutskiy <artem.bityutskiy at linux.intel.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Brian Norris <computersforpeace at gmail.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
fs/jffs2/nodemgmt.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/fs/jffs2/nodemgmt.c b/fs/jffs2/nodemgmt.c
index bbae5b1..b6bd4af 100644
--- a/fs/jffs2/nodemgmt.c
+++ b/fs/jffs2/nodemgmt.c
@@ -212,20 +212,25 @@ out:
int jffs2_reserve_space_gc(struct jffs2_sb_info *c, uint32_t minsize,
uint32_t *len, uint32_t sumsize)
{
- int ret = -EAGAIN;
+ int ret;
minsize = PAD(minsize);
jffs2_dbg(1, "%s(): Requested 0x%x bytes\n", __func__, minsize);
- spin_lock(&c->erase_completion_lock);
- while(ret == -EAGAIN) {
+ while (true) {
+ spin_lock(&c->erase_completion_lock);
ret = jffs2_do_reserve_space(c, minsize, len, sumsize);
if (ret) {
jffs2_dbg(1, "%s(): looping, ret is %d\n",
__func__, ret);
}
+ spin_unlock(&c->erase_completion_lock);
+
+ if (ret == -EAGAIN)
+ cond_resched();
+ else
+ break;
}
- spin_unlock(&c->erase_completion_lock);
if (!ret)
ret = jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
--
1.9.1
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