From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ie0-x234.google.com ([2607:f8b0:4001:c03::234]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WIUES-0007Lo-PT for linux-mtd@lists.infradead.org; Wed, 26 Feb 2014 02:28:25 +0000 Received: by mail-ie0-f180.google.com with SMTP id ar20so173226iec.11 for ; Tue, 25 Feb 2014 18:28:03 -0800 (PST) From: Brian Norris To: Subject: [PATCH] jffs2: fix unbalanced locking Date: Tue, 25 Feb 2014 18:27:40 -0800 Message-Id: <1393381660-26150-1-git-send-email-computersforpeace@gmail.com> Cc: Artem Bityutskiy , Li Zefan , Brian Norris , David Woodhouse , Andrew Morton List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Li Zefan reported an unbalanced locking issue, found by his internal debugging feature on runtime. The particular case he was looking at doesn't lead to a deadlock, as the structure that this lock is embedded in is freed on error. But we should straighten out the error handling. Because several callers of jffs2_do_read_inode_internal() / jffs2_do_read_inode() already handle the locking/unlocking and inode clearing at their own level, let's just push any unlocks/clearing down to the caller. This consistency is much easier to verify. Reported-by: Li Zefan Cc: David Woodhouse Cc: Artem Bityutskiy Cc: Andrew Morton Signed-off-by: Brian Norris --- Not CC'd to -stable this time, since the bug seems non-critical, and it has only limited testing (I did a few quick sanity tests, and Li tested an earlier revision) fs/jffs2/fs.c | 7 ++----- fs/jffs2/readinode.c | 27 ++++----------------------- 2 files changed, 6 insertions(+), 28 deletions(-) diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c index 560821bff038..ea753a2a893e 100644 --- a/fs/jffs2/fs.c +++ b/fs/jffs2/fs.c @@ -272,12 +272,9 @@ struct inode *jffs2_iget(struct super_block *sb, unsigned long ino) mutex_lock(&f->sem); ret = jffs2_do_read_inode(c, f, inode->i_ino, &latest_node); + if (ret) + goto error; - if (ret) { - mutex_unlock(&f->sem); - iget_failed(inode); - return ERR_PTR(ret); - } inode->i_mode = jemode_to_cpu(latest_node.mode); i_uid_write(inode, je16_to_cpu(latest_node.uid)); i_gid_write(inode, je16_to_cpu(latest_node.gid)); diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c index 386303dca382..5539ed46e89b 100644 --- a/fs/jffs2/readinode.c +++ b/fs/jffs2/readinode.c @@ -1203,17 +1203,13 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c, 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; + return ret ? ret : -EIO; } 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; } @@ -1250,16 +1246,11 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c, * keep in RAM to facilitate quick follow symlink * 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); + if (csize > JFFS2_MAX_NAME_LEN) return -ENAMETOOLONG; - } 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; } @@ -1271,8 +1262,6 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c, ret = -EIO; kfree(f->target); f->target = NULL; - mutex_unlock(&f->sem); - jffs2_do_clear_inode(c, f); return ret; } @@ -1289,15 +1278,11 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c, 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; } 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; } /* ASSERT: f->fraglist != NULL */ @@ -1305,8 +1290,6 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c, 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; } /* OK. We're happy */ @@ -1400,10 +1383,8 @@ int jffs2_do_crccheck_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *i f->inocache = ic; ret = jffs2_do_read_inode_internal(c, f, &n); - if (!ret) { - mutex_unlock(&f->sem); - jffs2_do_clear_inode(c, f); - } + mutex_unlock(&f->sem); + jffs2_do_clear_inode(c, f); jffs2_xattr_do_crccheck_inode(c, ic); kfree (f); return ret; -- 1.8.3.2