2018-10-19 08:31:42

by Daniel Santos

Subject: [PATCH] jffs2: Fix use of uninitialized delayed_work, lockdep breakage

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 <[email protected]>
---
fs/jffs2/super.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index 793ad30970ff..cae4ecda3c50 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -101,7 +101,8 @@ static int jffs2_sync_fs(struct super_block *sb, int wait)
struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);

#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
- cancel_delayed_work_sync(&c->wbuf_dwork);
+ if (jffs2_is_writebuffered(c))
+ cancel_delayed_work_sync(&c->wbuf_dwork);
#endif

mutex_lock(&c->alloc_sem);
--
2.16.4

2018-10-22 00:35:11

by Hou Tao

Subject: Re: [PATCH] jffs2: Fix use of uninitialized delayed_work, lockdep breakage

On 2018/10/19 16:30, 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 <[email protected]>
> ---
> fs/jffs2/super.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
> index 793ad30970ff..cae4ecda3c50 100644
> --- a/fs/jffs2/super.c
> +++ b/fs/jffs2/super.c
> @@ -101,7 +101,8 @@ static int jffs2_sync_fs(struct super_block *sb, int wait)
> struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
>
> #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
> - cancel_delayed_work_sync(&c->wbuf_dwork);
> + if (jffs2_is_writebuffered(c))
> + cancel_delayed_work_sync(&c->wbuf_dwork);
> #endif
>
> mutex_lock(&c->alloc_sem);
>

Reviewed-by: Hou Tao <[email protected]>

And I am curious that why is there NAND Flash without OOB area ? So for them
the ECC data must be saved in data area ?

Regards,

Tao

2018-10-22 04:59:47

by Daniel Santos

Subject: Re: [PATCH] jffs2: Fix use of uninitialized delayed_work, lockdep breakage

On 10/21/2018 07:32 PM, Hou Tao wrote:
>
> On 2018/10/19 16:30, 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 <[email protected]>
>> ---
>> fs/jffs2/super.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
>> index 793ad30970ff..cae4ecda3c50 100644
>> --- a/fs/jffs2/super.c
>> +++ b/fs/jffs2/super.c
>> @@ -101,7 +101,8 @@ static int jffs2_sync_fs(struct super_block *sb, int wait)
>> struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
>>
>> #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
>> - cancel_delayed_work_sync(&c->wbuf_dwork);
>> + if (jffs2_is_writebuffered(c))
>> + cancel_delayed_work_sync(&c->wbuf_dwork);
>> #endif
>>
>> mutex_lock(&c->alloc_sem);
>>
> Reviewed-by: Hou Tao <[email protected]>
>
> And I am curious that why is there NAND Flash without OOB area ? So for them
> the ECC data must be saved in data area ?
>
> Regards,
>
> Tao

Thank you.

I'm not intimately familiar with these, but it's an SPI NOR chip and I'm
pretty sure they that they don't have ECC.  Specifically a Winbond
w25q128fv using drivers/mtd/devices/m25p80.c.

Thanks,
Daniel

2018-11-05 21:42:11

by Daniel Santos

Subject: [PING][PATCH] jffs2: Fix use of uninitialized delayed_work, lockdep breakage

Ping.

Daniel

On 10/21/2018 07:32 PM, Hou Tao wrote:
>
> On 2018/10/19 16:30, 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 <[email protected]>
>> ---
>> fs/jffs2/super.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
>> index 793ad30970ff..cae4ecda3c50 100644
>> --- a/fs/jffs2/super.c
>> +++ b/fs/jffs2/super.c
>> @@ -101,7 +101,8 @@ static int jffs2_sync_fs(struct super_block *sb, int wait)
>> struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
>>
>> #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
>> - cancel_delayed_work_sync(&c->wbuf_dwork);
>> + if (jffs2_is_writebuffered(c))
>> + cancel_delayed_work_sync(&c->wbuf_dwork);
>> #endif
>>
>> mutex_lock(&c->alloc_sem);
>>
> Reviewed-by: Hou Tao <[email protected]>
>
> And I am curious that why is there NAND Flash without OOB area ? So for them
> the ECC data must be saved in data area ?
>
> Regards,
>
> Tao
>
>
>

2018-11-24 15:38:59

by Daniel Santos

Subject: [PING 2] [PATCH] jffs2: Fix use of uninitialized delayed_work, lockdep breakage

Ping 2!

On 11/05/2018 03:38 PM, Daniel Santos wrote:
> Ping.
>
> Daniel
>
> On 10/21/2018 07:32 PM, Hou Tao wrote:
>> On 2018/10/19 16:30, 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 <[email protected]>
>>> ---
>>> fs/jffs2/super.c | 3 ++-
>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
>>> index 793ad30970ff..cae4ecda3c50 100644
>>> --- a/fs/jffs2/super.c
>>> +++ b/fs/jffs2/super.c
>>> @@ -101,7 +101,8 @@ static int jffs2_sync_fs(struct super_block *sb, int wait)
>>> struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
>>>
>>> #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
>>> - cancel_delayed_work_sync(&c->wbuf_dwork);
>>> + if (jffs2_is_writebuffered(c))
>>> + cancel_delayed_work_sync(&c->wbuf_dwork);
>>> #endif
>>>
>>> mutex_lock(&c->alloc_sem);
>>>
>> Reviewed-by: Hou Tao <[email protected]>
>>
>> And I am curious that why is there NAND Flash without OOB area ? So for them
>> the ECC data must be saved in data area ?
>>
>> Regards,
>>
>> Tao
>>
>>
>>

2018-11-24 20:49:20

by Richard Weinberger

Subject: Re: [PING 2] [PATCH] jffs2: Fix use of uninitialized delayed_work, lockdep breakage

On Sat, Nov 24, 2018 at 4:32 PM Daniel Santos <[email protected]> wrote:
>
> Ping 2!
>
> On 11/05/2018 03:38 PM, Daniel Santos wrote:
> > Ping.
> >
> > Daniel
> >
> > On 10/21/2018 07:32 PM, Hou Tao wrote:
> >> On 2018/10/19 16:30, 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 <[email protected]>
> >>> ---
> >>> fs/jffs2/super.c | 3 ++-
> >>> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
> >>> index 793ad30970ff..cae4ecda3c50 100644
> >>> --- a/fs/jffs2/super.c
> >>> +++ b/fs/jffs2/super.c
> >>> @@ -101,7 +101,8 @@ static int jffs2_sync_fs(struct super_block *sb, int wait)
> >>> struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
> >>>
> >>> #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
> >>> - cancel_delayed_work_sync(&c->wbuf_dwork);
> >>> + if (jffs2_is_writebuffered(c))
> >>> + cancel_delayed_work_sync(&c->wbuf_dwork);
> >>> #endif
> >>>
> >>> mutex_lock(&c->alloc_sem);
> >>>
> >> Reviewed-by: Hou Tao <[email protected]>

Boris, can you please queue up this patch?

--
Thanks,
//richard

2018-12-03 07:54:47

by Boris Brezillon

Subject: Re: jffs2: Fix use of uninitialized delayed_work, lockdep breakage

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 <[email protected]>
> Reviewed-by: Hou Tao <[email protected]>

Applied to http://git.infradead.org/linux-mtd.git mtd/next, thanks.

Boris