target/linux/generic/pending-4.19/142-jffs2-Fix-use-of-uninitialized-delayed_work-lockdep-.patch

   1 From a788c5272769ddbcdbab297cf386413eeac04463 Mon Sep 17 00:00:00 2001
   2 From: Daniel Santos <daniel.santos@pobox.com>
   3 Date: Fri, 19 Oct 2018 03:30:20 -0500
   4 Subject: [PATCH] jffs2: Fix use of uninitialized delayed_work, lockdep
   5  breakage
   6
   7 jffs2_sync_fs makes the assumption that if CONFIG_JFFS2_FS_WRITEBUFFER
   8 is defined then a write buffer is available and has been initialized.
   9 However, this does is not the case when the mtd device has no
  10 out-of-band buffer:
  11
  12 int jffs2_nand_flash_setup(struct jffs2_sb_info *c)
  13 {
  14         if (!c->mtd->oobsize)
  15                 return 0;
  16 ...
  17
  18 The resulting call to cancel_delayed_work_sync passing a uninitialized
  19 (but zeroed) delayed_work struct forces lockdep to become disabled.
  20
  21 [   90.050639] overlayfs: upper fs does not support tmpfile.
  22 [   90.652264] INFO: trying to register non-static key.
  23 [   90.662171] the code is fine but needs lockdep annotation.
  24 [   90.673090] turning off the locking correctness validator.
  25 [   90.684021] CPU: 0 PID: 1762 Comm: mount_root Not tainted 4.14.63 #0
  26 [   90.696672] Stack : 00000000 00000000 80d8f6a2 00000038 805f0000 80444600 8fe364f4 805dfbe7
  27 [   90.713349]         80563a30 000006e2 8068370c 00000001 00000000 00000001 8e2fdc48 ffffffff
  28 [   90.730020]         00000000 00000000 80d90000 00000000 00000106 00000000 6465746e 312e3420
  29 [   90.746690]         6b636f6c 03bf0000 f8000000 20676e69 00000000 80000000 00000000 8e2c2a90
  30 [   90.763362]         80d90000 00000001 00000000 8e2c2a90 00000003 80260dc0 08052098 80680000
  31 [   90.780033]         ...
  32 [   90.784902] Call Trace:
  33 [   90.789793] [<8000f0d8>] show_stack+0xb8/0x148
  34 [   90.798659] [<8005a000>] register_lock_class+0x270/0x55c
  35 [   90.809247] [<8005cb64>] __lock_acquire+0x13c/0xf7c
  36 [   90.818964] [<8005e314>] lock_acquire+0x194/0x1dc
  37 [   90.828345] [<8003f27c>] flush_work+0x200/0x24c
  38 [   90.837374] [<80041dfc>] __cancel_work_timer+0x158/0x210
  39 [   90.847958] [<801a8770>] jffs2_sync_fs+0x20/0x54
  40 [   90.857173] [<80125cf4>] iterate_supers+0xf4/0x120
  41 [   90.866729] [<80158fc4>] sys_sync+0x44/0x9c
  42 [   90.875067] [<80014424>] syscall_common+0x34/0x58
  43
  44 Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
  45 Reviewed-by: Hou Tao <houtao1@huawei.com>
  46 Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
  47 ---
  48  fs/jffs2/super.c | 3 ++-
  49  1 file changed, 2 insertions(+), 1 deletion(-)
  50
  51 --- a/fs/jffs2/super.c
  52 +++ b/fs/jffs2/super.c
  53 @@ -101,7 +101,8 @@ static int jffs2_sync_fs(struct super_bl
  54         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  55
  56  #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
  57 -       cancel_delayed_work_sync(&c->wbuf_dwork);
  58 +       if (jffs2_is_writebuffered(c))
  59 +               cancel_delayed_work_sync(&c->wbuf_dwork);
  60  #endif
  61
  62         mutex_lock(&c->alloc_sem);