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| author | Luis Henriques <lhenriques@suse.com> | 2019-07-19 15:32:20 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-10 10:32:18 +0100 |
| commit | de30fc2ca852365ed635f62d7d818bffc15e55c9 (patch) | |
| tree | 3dd5ac8f800bf24472b4ee39a276ff67fdd4896f | |
| parent | 2481742320ddff94be4ebf93545f11952c9e5e77 (diff) | |
| download | linux-stable-de30fc2ca852365ed635f62d7d818bffc15e55c9.tar.gz linux-stable-de30fc2ca852365ed635f62d7d818bffc15e55c9.tar.bz2 linux-stable-de30fc2ca852365ed635f62d7d818bffc15e55c9.zip | |
ceph: fix buffer free while holding i_ceph_lock in __ceph_setxattr()
[ Upstream commit 86968ef21596515958d5f0a40233d02be78ecec0 ]
Calling ceph_buffer_put() in __ceph_setxattr() may end up freeing the
i_xattrs.prealloc_blob buffer while holding the i_ceph_lock. This can be
fixed by postponing the call until later, when the lock is released.
The following backtrace was triggered by fstests generic/117.
BUG: sleeping function called from invalid context at mm/vmalloc.c:2283
in_atomic(): 1, irqs_disabled(): 0, pid: 650, name: fsstress
3 locks held by fsstress/650:
#0: 00000000870a0fe8 (sb_writers#8){.+.+}, at: mnt_want_write+0x20/0x50
#1: 00000000ba0c4c74 (&type->i_mutex_dir_key#6){++++}, at: vfs_setxattr+0x55/0xa0
#2: 000000008dfbb3f2 (&(&ci->i_ceph_lock)->rlock){+.+.}, at: __ceph_setxattr+0x297/0x810
CPU: 1 PID: 650 Comm: fsstress Not tainted 5.2.0+ #437
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-prebuilt.qemu.org 04/01/2014
Call Trace:
dump_stack+0x67/0x90
___might_sleep.cold+0x9f/0xb1
vfree+0x4b/0x60
ceph_buffer_release+0x1b/0x60
__ceph_setxattr+0x2b4/0x810
__vfs_setxattr+0x66/0x80
__vfs_setxattr_noperm+0x59/0xf0
vfs_setxattr+0x81/0xa0
setxattr+0x115/0x230
? filename_lookup+0xc9/0x140
? rcu_read_lock_sched_held+0x74/0x80
? rcu_sync_lockdep_assert+0x2e/0x60
? __sb_start_write+0x142/0x1a0
? mnt_want_write+0x20/0x50
path_setxattr+0xba/0xd0
__x64_sys_lsetxattr+0x24/0x30
do_syscall_64+0x50/0x1c0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7ff23514359a
Signed-off-by: Luis Henriques <lhenriques@suse.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/ceph/xattr.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c index 0376db8a74f8..932c6cdc22d6 100644 --- a/fs/ceph/xattr.c +++ b/fs/ceph/xattr.c @@ -955,6 +955,7 @@ int __ceph_setxattr(struct inode *inode, const char *name, struct ceph_inode_info *ci = ceph_inode(inode); struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc; struct ceph_cap_flush *prealloc_cf = NULL; + struct ceph_buffer *old_blob = NULL; int issued; int err; int dirty = 0; @@ -1023,13 +1024,15 @@ retry: struct ceph_buffer *blob; spin_unlock(&ci->i_ceph_lock); - dout(" preaallocating new blob size=%d\n", required_blob_size); + ceph_buffer_put(old_blob); /* Shouldn't be required */ + dout(" pre-allocating new blob size=%d\n", required_blob_size); blob = ceph_buffer_new(required_blob_size, GFP_NOFS); if (!blob) goto do_sync_unlocked; spin_lock(&ci->i_ceph_lock); + /* prealloc_blob can't be released while holding i_ceph_lock */ if (ci->i_xattrs.prealloc_blob) - ceph_buffer_put(ci->i_xattrs.prealloc_blob); + old_blob = ci->i_xattrs.prealloc_blob; ci->i_xattrs.prealloc_blob = blob; goto retry; } @@ -1045,6 +1048,7 @@ retry: } spin_unlock(&ci->i_ceph_lock); + ceph_buffer_put(old_blob); if (lock_snap_rwsem) up_read(&mdsc->snap_rwsem); if (dirty) |