From: Luis Henriques lhenriques@suse.com
[ Upstream commit af8a85a41734f37b67ba8ce69d56b685bee4ac48 ]
Calling ceph_buffer_put() in fill_inode() may result in freeing the i_xattrs.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/070.
BUG: sleeping function called from invalid context at mm/vmalloc.c:2283 in_atomic(): 1, irqs_disabled(): 0, pid: 3852, name: kworker/0:4 6 locks held by kworker/0:4/3852: #0: 000000004270f6bb ((wq_completion)ceph-msgr){+.+.}, at: process_one_work+0x1b8/0x5f0 #1: 00000000eb420803 ((work_completion)(&(&con->work)->work)){+.+.}, at: process_one_work+0x1b8/0x5f0 #2: 00000000be1c53a4 (&s->s_mutex){+.+.}, at: dispatch+0x288/0x1476 #3: 00000000559cb958 (&mdsc->snap_rwsem){++++}, at: dispatch+0x2eb/0x1476 #4: 000000000d5ebbae (&req->r_fill_mutex){+.+.}, at: dispatch+0x2fc/0x1476 #5: 00000000a83d0514 (&(&ci->i_ceph_lock)->rlock){+.+.}, at: fill_inode.isra.0+0xf8/0xf70 CPU: 0 PID: 3852 Comm: kworker/0:4 Not tainted 5.2.0+ #441 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-prebuilt.qemu.org 04/01/2014 Workqueue: ceph-msgr ceph_con_workfn Call Trace: dump_stack+0x67/0x90 ___might_sleep.cold+0x9f/0xb1 vfree+0x4b/0x60 ceph_buffer_release+0x1b/0x60 fill_inode.isra.0+0xa9b/0xf70 ceph_fill_trace+0x13b/0xc70 ? dispatch+0x2eb/0x1476 dispatch+0x320/0x1476 ? __mutex_unlock_slowpath+0x4d/0x2a0 ceph_con_workfn+0xc97/0x2ec0 ? process_one_work+0x1b8/0x5f0 process_one_work+0x244/0x5f0 worker_thread+0x4d/0x3e0 kthread+0x105/0x140 ? process_one_work+0x5f0/0x5f0 ? kthread_park+0x90/0x90 ret_from_fork+0x3a/0x50
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 --- fs/ceph/inode.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index f2b722f0df5d0..9bda8c7a80a05 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -730,6 +730,7 @@ static int fill_inode(struct inode *inode, struct page *locked_page, int issued = 0, implemented, new_issued; struct timespec mtime, atime, ctime; struct ceph_buffer *xattr_blob = NULL; + struct ceph_buffer *old_blob = NULL; struct ceph_string *pool_ns = NULL; struct ceph_cap *new_cap = NULL; int err = 0; @@ -847,7 +848,7 @@ static int fill_inode(struct inode *inode, struct page *locked_page, if ((ci->i_xattrs.version == 0 || !(issued & CEPH_CAP_XATTR_EXCL)) && le64_to_cpu(info->xattr_version) > ci->i_xattrs.version) { if (ci->i_xattrs.blob) - ceph_buffer_put(ci->i_xattrs.blob); + old_blob = ci->i_xattrs.blob; ci->i_xattrs.blob = xattr_blob; if (xattr_blob) memcpy(ci->i_xattrs.blob->vec.iov_base, @@ -993,8 +994,8 @@ static int fill_inode(struct inode *inode, struct page *locked_page, out: if (new_cap) ceph_put_cap(mdsc, new_cap); - if (xattr_blob) - ceph_buffer_put(xattr_blob); + ceph_buffer_put(old_blob); + ceph_buffer_put(xattr_blob); ceph_put_string(pool_ns); return err; }