Re: jffs2: Fix use of uninitialized delayed_work, lockdep breakage
From: Boris Brezillon
Date: Mon Dec 03 2018 - 02:52:22 EST
On Fri, 2018-10-19 at 08:30:20 UTC, Daniel Santos wrote:
> jffs2_sync_fs makes the assumption that if CONFIG_JFFS2_FS_WRITEBUFFER
> is defined then a write buffer is available and has been initialized.
> However, this does is not the case when the mtd device has no
> out-of-band buffer:
>
> int jffs2_nand_flash_setup(struct jffs2_sb_info *c)
> {
> if (!c->mtd->oobsize)
> return 0;
> ...
>
> The resulting call to cancel_delayed_work_sync passing a uninitialized
> (but zeroed) delayed_work struct forces lockdep to become disabled.
>
> [ 90.050639] overlayfs: upper fs does not support tmpfile.
> [ 90.652264] INFO: trying to register non-static key.
> [ 90.662171] the code is fine but needs lockdep annotation.
> [ 90.673090] turning off the locking correctness validator.
> [ 90.684021] CPU: 0 PID: 1762 Comm: mount_root Not tainted 4.14.63 #0
> [ 90.696672] Stack : 00000000 00000000 80d8f6a2 00000038 805f0000 80444600 8fe364f4 805dfbe7
> [ 90.713349] 80563a30 000006e2 8068370c 00000001 00000000 00000001 8e2fdc48 ffffffff
> [ 90.730020] 00000000 00000000 80d90000 00000000 00000106 00000000 6465746e 312e3420
> [ 90.746690] 6b636f6c 03bf0000 f8000000 20676e69 00000000 80000000 00000000 8e2c2a90
> [ 90.763362] 80d90000 00000001 00000000 8e2c2a90 00000003 80260dc0 08052098 80680000
> [ 90.780033] ...
> [ 90.784902] Call Trace:
> [ 90.789793] [<8000f0d8>] show_stack+0xb8/0x148
> [ 90.798659] [<8005a000>] register_lock_class+0x270/0x55c
> [ 90.809247] [<8005cb64>] __lock_acquire+0x13c/0xf7c
> [ 90.818964] [<8005e314>] lock_acquire+0x194/0x1dc
> [ 90.828345] [<8003f27c>] flush_work+0x200/0x24c
> [ 90.837374] [<80041dfc>] __cancel_work_timer+0x158/0x210
> [ 90.847958] [<801a8770>] jffs2_sync_fs+0x20/0x54
> [ 90.857173] [<80125cf4>] iterate_supers+0xf4/0x120
> [ 90.866729] [<80158fc4>] sys_sync+0x44/0x9c
> [ 90.875067] [<80014424>] syscall_common+0x34/0x58
>
> Signed-off-by: Daniel Santos <daniel.santos@xxxxxxxxx>
> Reviewed-by: Hou Tao <houtao1@xxxxxxxxxx>
Applied to http://git.infradead.org/linux-mtd.git mtd/next, thanks.
Boris