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[PATCH 4.4 10/25] reiserfs: Unlock superblock before calling reiserfs_quota_on_mount()

From Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups linux.kernel
Subject [PATCH 4.4 10/25] reiserfs: Unlock superblock before calling reiserfs_quota_on_mount()
Date 2016-10-21 11:50 +0200
Message-ID <suECB-3Ib-15@gated-at.bofh.it> (permalink)
References <suE9A-3xe-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mike Galbraith <efault@gmx.de>

commit 420902c9d086848a7548c83e0a49021514bd71b7 upstream.

If we hold the superblock lock while calling reiserfs_quota_on_mount(), we can
deadlock our own worker - mount blocks kworker/3:2, sleeps forever more.

crash> ps|grep UN
    715      2   3  ffff880220734d30  UN   0.0       0      0  [kworker/3:2]
   9369   9341   2  ffff88021ffb7560  UN   1.3  493404 123184  Xorg
   9665   9664   3  ffff880225b92ab0  UN   0.0   47368    812  udisks-daemon
  10635  10403   3  ffff880222f22c70  UN   0.0   14904    936  mount
crash> bt ffff880220734d30
PID: 715    TASK: ffff880220734d30  CPU: 3   COMMAND: "kworker/3:2"
 #0 [ffff8802244c3c20] schedule at ffffffff8144584b
 #1 [ffff8802244c3cc8] __rt_mutex_slowlock at ffffffff814472b3
 #2 [ffff8802244c3d28] rt_mutex_slowlock at ffffffff814473f5
 #3 [ffff8802244c3dc8] reiserfs_write_lock at ffffffffa05f28fd [reiserfs]
 #4 [ffff8802244c3de8] flush_async_commits at ffffffffa05ec91d [reiserfs]
 #5 [ffff8802244c3e08] process_one_work at ffffffff81073726
 #6 [ffff8802244c3e68] worker_thread at ffffffff81073eba
 #7 [ffff8802244c3ec8] kthread at ffffffff810782e0
 #8 [ffff8802244c3f48] kernel_thread_helper at ffffffff81450064
crash> rd ffff8802244c3cc8 10
ffff8802244c3cc8:  ffffffff814472b3 ffff880222f23250   .rD.....P2."....
ffff8802244c3cd8:  0000000000000000 0000000000000286   ................
ffff8802244c3ce8:  ffff8802244c3d30 ffff880220734d80   0=L$.....Ms ....
ffff8802244c3cf8:  ffff880222e8f628 0000000000000000   (.."............
ffff8802244c3d08:  0000000000000000 0000000000000002   ................
crash> struct rt_mutex ffff880222e8f628
struct rt_mutex {
  wait_lock = {
    raw_lock = {
      slock = 65537
    }
  },
  wait_list = {
    node_list = {
      next = 0xffff8802244c3d48,
      prev = 0xffff8802244c3d48
    }
  },
  owner = 0xffff880222f22c71,
  save_state = 0
}
crash> bt 0xffff880222f22c70
PID: 10635  TASK: ffff880222f22c70  CPU: 3   COMMAND: "mount"
 #0 [ffff8802216a9868] schedule at ffffffff8144584b
 #1 [ffff8802216a9910] schedule_timeout at ffffffff81446865
 #2 [ffff8802216a99a0] wait_for_common at ffffffff81445f74
 #3 [ffff8802216a9a30] flush_work at ffffffff810712d3
 #4 [ffff8802216a9ab0] schedule_on_each_cpu at ffffffff81074463
 #5 [ffff8802216a9ae0] invalidate_bdev at ffffffff81178aba
 #6 [ffff8802216a9af0] vfs_load_quota_inode at ffffffff811a3632
 #7 [ffff8802216a9b50] dquot_quota_on_mount at ffffffff811a375c
 #8 [ffff8802216a9b80] finish_unfinished at ffffffffa05dd8b0 [reiserfs]
 #9 [ffff8802216a9cc0] reiserfs_fill_super at ffffffffa05de825 [reiserfs]
    RIP: 00007f7b9303997a  RSP: 00007ffff443c7a8  RFLAGS: 00010202
    RAX: 00000000000000a5  RBX: ffffffff8144ef12  RCX: 00007f7b932e9ee0
    RDX: 00007f7b93d9a400  RSI: 00007f7b93d9a3e0  RDI: 00007f7b93d9a3c0
    RBP: 00007f7b93d9a2c0   R8: 00007f7b93d9a550   R9: 0000000000000001
    R10: ffffffffc0ed040e  R11: 0000000000000202  R12: 000000000000040e
    R13: 0000000000000000  R14: 00000000c0ed040e  R15: 00007ffff443ca20
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Mike Galbraith <mgalbraith@suse.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/reiserfs/super.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -190,7 +190,15 @@ static int remove_save_link_only(struct
 static int reiserfs_quota_on_mount(struct super_block *, int);
 #endif
 
-/* look for uncompleted unlinks and truncates and complete them */
+/*
+ * Look for uncompleted unlinks and truncates and complete them
+ *
+ * Called with superblock write locked.  If quotas are enabled, we have to
+ * release/retake lest we call dquot_quota_on_mount(), proceed to
+ * schedule_on_each_cpu() in invalidate_bdev() and deadlock waiting for the per
+ * cpu worklets to complete flush_async_commits() that in turn wait for the
+ * superblock write lock.
+ */
 static int finish_unfinished(struct super_block *s)
 {
 	INITIALIZE_PATH(path);
@@ -237,7 +245,9 @@ static int finish_unfinished(struct supe
 				quota_enabled[i] = 0;
 				continue;
 			}
+			reiserfs_write_unlock(s);
 			ret = reiserfs_quota_on_mount(s, i);
+			reiserfs_write_lock(s);
 			if (ret < 0)
 				reiserfs_warning(s, "reiserfs-2500",
 						 "cannot turn on journaled "

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[PATCH 4.4 00/25] 4.4.27-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 06/25] fuse: fix killing s[ug]id in setattr Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 09/25] ASoC: Intel: Atom: add a missing star in a memcpy call Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 14/25] scsi: arcmsr: Simplify user_len checking Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 01/25] serial: 8250_dw: Check the data->pclk when get apb_pclk Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 11/25] reiserfs: switch to generic_{get,set,remove}xattr() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 25/25] cfq: fix starvation of asynchronous writes Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 18/25] ext4: fix memory leak in ext4_insert_range() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 12/25] async_pq_val: fix DMA memory leak Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 13/25] scsi: arcmsr: Buffer overflow in arcmsr_iop_message_xfer() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 16/25] ext4: enforce online defrag restriction for encrypted files Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 03/25] drivers: base: dma-mapping: page align the size when unmap_kernel_range Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 02/25] btrfs: assign error values to the correct bio structs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:20 +0200
  [PATCH 4.4 04/25] fuse: listxattr: verify xattr list Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.4 24/25] vfs: move permission checking into notify_change() for utimes(NULL) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.4 17/25] ext4: reinforce check of i_dtime when clearing high fields of uid and gid Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.4 10/25] reiserfs: Unlock superblock before calling reiserfs_quota_on_mount() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.4 15/25] scsi: ibmvfc: Fix I/O hang when port is not mapped Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.4 20/25] ext4: release bh in make_indexed_dir Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.4 19/25] ext4: allow DAX writeback for hole punch Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.4 22/25] crypto: vmx - Fix memory corruption caused by p8_ghash Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  Re: [PATCH 4.4 00/25] 4.4.27-stable review Shuah Khan <shuah.kh@samsung.com> - 2016-10-21 17:50 +0200
  Re: [PATCH 4.4 00/25] 4.4.27-stable review Guenter Roeck <linux@roeck-us.net> - 2016-10-21 21:20 +0200

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