From: Li Zefan <lizefan@xxxxxxxxxx>
Subject: jffs2: avoid soft-lockup in jffs2_reserve_space_gc()
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@xxxxxxxxxxxxxxxxxxxx: don't initialize `ret']
Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Brian Norris <computersforpeace@xxxxxxxxx>
Cc: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/jffs2/nodemgmt.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff -puN fs/jffs2/nodemgmt.c~jffs2-avoid-soft-lockup-in-jffs2_reserve_space_gc fs/jffs2/nodemgmt.c
--- a/fs/jffs2/nodemgmt.c~jffs2-avoid-soft-lockup-in-jffs2_reserve_space_gc
+++ a/fs/jffs2/nodemgmt.c
@@ -211,20 +211,25 @@ 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);
_
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html