• Luis Henriques's avatar
    ceph: fix buffer free while holding i_ceph_lock in __ceph_setxattr() · 60fd5a05
    Luis Henriques authored
    BugLink: https://bugs.launchpad.net/bugs/1845374
    
    [ Upstream commit 86968ef2 ]
    
    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: default avatarLuis Henriques <lhenriques@suse.com>
    Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
    Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
    Signed-off-by: default avatarConnor Kuehl <connor.kuehl@canonical.com>
    Signed-off-by: default avatarKhalid Elmously <khalid.elmously@canonical.com>
    60fd5a05
xattr.c 29.1 KB