Subject: + jffs2-fix-unbalanced-locking-v2.patch added to -mm tree
To: lizefan@xxxxxxxxxx,artem.bityutskiy@xxxxxxxxxxxxxxx,computersforpeace@xxxxxxxxx,dwmw2@xxxxxxxxxxxxx,stable@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 13 Feb 2014 13:08:39 -0800
The patch titled
Subject: jffs2: fix unbalanced locking
has been added to the -mm tree. Its filename is
jffs2-fix-unbalanced-locking-v2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/jffs2-fix-unbalanced-locking-v2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/jffs2-fix-unbalanced-locking-v2.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Li Zefan <lizefan@xxxxxxxxxx>
Subject: jffs2: fix unbalanced locking
On runtime our internal debugging feature warned f->sem isn't unlocked
when returning to userspace. It's because f->sem isn't unlocked in
jffs2_do_crccheck_inode() on error, but this bug won't lead to deadlock,
as the structure that this lock is embedded in is freed immediately.
After looking into the code, I found in jffs2_do_read_inode_internal()
some error paths release f->sem but some won't, so this may lead to
double-unlock:
jffs2_iget()
|_ mutex_lock(&f->sem)
|_ jffs2_do_read_inode()
| |_ jffs2_do_read_inode_internal()
| |_ mutex_unlock(&f->sem)
| |_ jffs2_do_clear_inode(c, f)
| |_ return ret
|_ mutex_unlock(&f->sem)
This patch makes sure jffs2_do_read_inode_internal() never returns with
f->sem unlocked, so locking and unlocking are in the same level.
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/readinode.c | 53 ++++++++++++++++++-----------------------
1 file changed, 24 insertions(+), 29 deletions(-)
diff -puN fs/jffs2/readinode.c~jffs2-fix-unbalanced-locking-v2 fs/jffs2/readinode.c
--- a/fs/jffs2/readinode.c~jffs2-fix-unbalanced-locking-v2
+++ a/fs/jffs2/readinode.c
@@ -1203,18 +1203,16 @@ static int jffs2_do_read_inode_internal(
JFFS2_ERROR("failed to read from flash: error %d, %zd of %zd bytes read\n",
ret, retlen, sizeof(*latest_node));
/* FIXME: If this fails, there seems to be a memory leak. Find it. */
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
- return ret?ret:-EIO;
+ ret = ret ? ret : -EIO;
+ goto out;
}
crc = crc32(0, latest_node, sizeof(*latest_node)-8);
if (crc != je32_to_cpu(latest_node->node_crc)) {
JFFS2_ERROR("CRC failed for read_inode of inode %u at physical location 0x%x\n",
f->inocache->ino, ref_offset(rii.latest_ref));
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
- return -EIO;
+ ret = -EIO;
+ goto out;
}
switch(jemode_to_cpu(latest_node->mode) & S_IFMT) {
@@ -1251,16 +1249,14 @@ static int jffs2_do_read_inode_internal(
* operation. */
uint32_t csize = je32_to_cpu(latest_node->csize);
if (csize > JFFS2_MAX_NAME_LEN) {
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
- return -ENAMETOOLONG;
+ ret = -ENAMETOOLONG;
+ goto out;
}
f->target = kmalloc(csize + 1, GFP_KERNEL);
if (!f->target) {
JFFS2_ERROR("can't allocate %u bytes of memory for the symlink target path cache\n", csize);
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto out;
}
ret = jffs2_flash_read(c, ref_offset(rii.latest_ref) + sizeof(*latest_node),
@@ -1271,9 +1267,7 @@ static int jffs2_do_read_inode_internal(
ret = -EIO;
kfree(f->target);
f->target = NULL;
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
- return ret;
+ goto out;
}
f->target[csize] = '\0';
@@ -1289,25 +1283,22 @@ static int jffs2_do_read_inode_internal(
if (f->metadata) {
JFFS2_ERROR("Argh. Special inode #%u with mode 0%o had metadata node\n",
f->inocache->ino, jemode_to_cpu(latest_node->mode));
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
- return -EIO;
+ ret = -EIO;
+ goto out;
}
if (!frag_first(&f->fragtree)) {
JFFS2_ERROR("Argh. Special inode #%u with mode 0%o has no fragments\n",
f->inocache->ino, jemode_to_cpu(latest_node->mode));
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
- return -EIO;
+ ret = -EIO;
+ goto out;
}
/* ASSERT: f->fraglist != NULL */
if (frag_next(frag_first(&f->fragtree))) {
JFFS2_ERROR("Argh. Special inode #%u with mode 0x%x had more than one node\n",
f->inocache->ino, jemode_to_cpu(latest_node->mode));
/* FIXME: Deal with it - check crc32, check for duplicate node, check times and discard the older one */
- mutex_unlock(&f->sem);
- jffs2_do_clear_inode(c, f);
- return -EIO;
+ ret = -EIO;
+ goto out;
}
/* OK. We're happy */
f->metadata = frag_first(&f->fragtree)->node;
@@ -1317,8 +1308,13 @@ static int jffs2_do_read_inode_internal(
}
if (f->inocache->state == INO_STATE_READING)
jffs2_set_inocache_state(c, f->inocache, INO_STATE_PRESENT);
-
- return 0;
+out:
+ if (ret) {
+ mutex_unlock(&f->sem);
+ jffs2_do_clear_inode(c, f);
+ mutex_lock(&f->sem);
+ }
+ return ret;
}
/* Scan the list of all nodes present for this ino, build map of versions, etc. */
@@ -1400,10 +1396,9 @@ int jffs2_do_crccheck_inode(struct jffs2
f->inocache = ic;
ret = jffs2_do_read_inode_internal(c, f, &n);
- if (!ret) {
- mutex_unlock(&f->sem);
+ mutex_unlock(&f->sem);
+ if (!ret)
jffs2_do_clear_inode(c, f);
- }
jffs2_xattr_do_crccheck_inode(c, ic);
kfree (f);
return ret;
_
Patches currently in -mm which might be from lizefan@xxxxxxxxxx are
jffs2-fix-unbalanced-locking-v2.patch
jffs2-fix-unbalanced-locking.patch
jffs2-avoid-soft-lockup-in-jffs2_reserve_space_gc.patch
jffs2-remove-wait-queue-after-schedule.patch
linux-next.patch
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