2024-01-16 22:34:52

by Daeho Jeong

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH v1] f2fs: fix NULL pointer dereference in f2fs_submit_page_write()

On Tue, Jan 16, 2024 at 6:13 AM Wenjie Qi <[email protected]> wrote:
>
> BUG: kernel NULL pointer dereference, address: 0000000000000014
> RIP: 0010:f2fs_submit_page_write+0x6cf/0x780 [f2fs]
> Call Trace:
> <TASK>
> ? show_regs+0x6e/0x80
> ? __die+0x29/0x70
> ? page_fault_oops+0x154/0x4a0
> ? prb_read_valid+0x20/0x30
> ? __irq_work_queue_local+0x39/0xd0
> ? irq_work_queue+0x36/0x70
> ? do_user_addr_fault+0x314/0x6c0
> ? exc_page_fault+0x7d/0x190
> ? asm_exc_page_fault+0x2b/0x30
> ? f2fs_submit_page_write+0x6cf/0x780 [f2fs]
> ? f2fs_submit_page_write+0x736/0x780 [f2fs]
> do_write_page+0x50/0x170 [f2fs]
> f2fs_outplace_write_data+0x61/0xb0 [f2fs]
> f2fs_do_write_data_page+0x3f8/0x660 [f2fs]
> f2fs_write_single_data_page+0x5bb/0x7a0 [f2fs]
> f2fs_write_cache_pages+0x3da/0xbe0 [f2fs]
> ...
> It is possible that other threads have added this fio to io->bio
> and submitted the io->bio before entering f2fs_submit_page_write().
> At this point io->bio = NULL.
> If is_end_zone_blkaddr(sbi, fio->new_blkaddr) of this fio is true,
> then an NULL pointer dereference error occurs at bio_get(io->bio).
> The original code for determining zone end was after "out:",
> which would have missed some fio who is zone end. I've moved
> this code before "skip:" to make sure it's done for each fio.
>
> Signed-off-by: Wenjie Qi <[email protected]>
> ---
> fs/f2fs/data.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index dce8defdf4c7..4f445906db8b 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1080,10 +1080,6 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> io->last_block_in_bio = fio->new_blkaddr;
>
> trace_f2fs_submit_page_write(fio->page, fio);
> -skip:
> - if (fio->in_list)
> - goto next;
> -out:
> #ifdef CONFIG_BLK_DEV_ZONED
> if (f2fs_sb_has_blkzoned(sbi) && btype < META &&
> is_end_zone_blkaddr(sbi, fio->new_blkaddr)) {
> @@ -1096,6 +1092,10 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> __submit_merged_bio(io);
> }
> #endif
> +skip:
> + if (fio->in_list)
> + goto next;
> +out:

How about moving only the "out" label instead of the whole block from
"skip" to "out"?

> if (is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN) ||
> !f2fs_is_checkpoint_ready(sbi))
> __submit_merged_bio(io);
> --
> 2.34.1
>
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel


2024-01-17 01:46:24

by Wenjie Qi

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH v1] f2fs: fix NULL pointer dereference in f2fs_submit_page_write()

Hello Daeho,
I don't think moving just the "out" label will work.
If a fio is zone end and in_list = 1, that fio is missed without being judged.

On Wed, Jan 17, 2024 at 5:58 AM Daeho Jeong <[email protected]> wrote:
>
> On Tue, Jan 16, 2024 at 6:13 AM Wenjie Qi <[email protected]> wrote:
> >
> > BUG: kernel NULL pointer dereference, address: 0000000000000014
> > RIP: 0010:f2fs_submit_page_write+0x6cf/0x780 [f2fs]
> > Call Trace:
> > <TASK>
> > ? show_regs+0x6e/0x80
> > ? __die+0x29/0x70
> > ? page_fault_oops+0x154/0x4a0
> > ? prb_read_valid+0x20/0x30
> > ? __irq_work_queue_local+0x39/0xd0
> > ? irq_work_queue+0x36/0x70
> > ? do_user_addr_fault+0x314/0x6c0
> > ? exc_page_fault+0x7d/0x190
> > ? asm_exc_page_fault+0x2b/0x30
> > ? f2fs_submit_page_write+0x6cf/0x780 [f2fs]
> > ? f2fs_submit_page_write+0x736/0x780 [f2fs]
> > do_write_page+0x50/0x170 [f2fs]
> > f2fs_outplace_write_data+0x61/0xb0 [f2fs]
> > f2fs_do_write_data_page+0x3f8/0x660 [f2fs]
> > f2fs_write_single_data_page+0x5bb/0x7a0 [f2fs]
> > f2fs_write_cache_pages+0x3da/0xbe0 [f2fs]
> > ...
> > It is possible that other threads have added this fio to io->bio
> > and submitted the io->bio before entering f2fs_submit_page_write().
> > At this point io->bio = NULL.
> > If is_end_zone_blkaddr(sbi, fio->new_blkaddr) of this fio is true,
> > then an NULL pointer dereference error occurs at bio_get(io->bio).
> > The original code for determining zone end was after "out:",
> > which would have missed some fio who is zone end. I've moved
> > this code before "skip:" to make sure it's done for each fio.
> >
> > Signed-off-by: Wenjie Qi <[email protected]>
> > ---
> > fs/f2fs/data.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index dce8defdf4c7..4f445906db8b 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -1080,10 +1080,6 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> > io->last_block_in_bio = fio->new_blkaddr;
> >
> > trace_f2fs_submit_page_write(fio->page, fio);
> > -skip:
> > - if (fio->in_list)
> > - goto next;
> > -out:
> > #ifdef CONFIG_BLK_DEV_ZONED
> > if (f2fs_sb_has_blkzoned(sbi) && btype < META &&
> > is_end_zone_blkaddr(sbi, fio->new_blkaddr)) {
> > @@ -1096,6 +1092,10 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> > __submit_merged_bio(io);
> > }
> > #endif
> > +skip:
> > + if (fio->in_list)
> > + goto next;
> > +out:
>
> How about moving only the "out" label instead of the whole block from
> "skip" to "out"?
>
> > if (is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN) ||
> > !f2fs_is_checkpoint_ready(sbi))
> > __submit_merged_bio(io);
> > --
> > 2.34.1
> >
> >
> >
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

2024-01-17 10:18:05

by Yongpeng Yang

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH v1] f2fs: fix NULL pointer dereference in f2fs_submit_page_write()

Hello Wenjie,
This patch does not prevent the simultaneous truth of
list_empty(&io->io_list), fio->in_list, and is_end_zone_blkaddr(sbi,
fio->new_blkaddr). NULL pointer dereference error still exists in
“bio_get(io->bio)”. Is that correct?

On 1/17/2024 9:39 AM, Wenjie Qi wrote:
> Hello Daeho,
> I don't think moving just the "out" label will work.
> If a fio is zone end and in_list = 1, that fio is missed without being judged.
>
> On Wed, Jan 17, 2024 at 5:58 AM Daeho Jeong <[email protected]> wrote:
>>
>> On Tue, Jan 16, 2024 at 6:13 AM Wenjie Qi <[email protected]> wrote:
>>>
>>> BUG: kernel NULL pointer dereference, address: 0000000000000014
>>> RIP: 0010:f2fs_submit_page_write+0x6cf/0x780 [f2fs]
>>> Call Trace:
>>> <TASK>
>>> ? show_regs+0x6e/0x80
>>> ? __die+0x29/0x70
>>> ? page_fault_oops+0x154/0x4a0
>>> ? prb_read_valid+0x20/0x30
>>> ? __irq_work_queue_local+0x39/0xd0
>>> ? irq_work_queue+0x36/0x70
>>> ? do_user_addr_fault+0x314/0x6c0
>>> ? exc_page_fault+0x7d/0x190
>>> ? asm_exc_page_fault+0x2b/0x30
>>> ? f2fs_submit_page_write+0x6cf/0x780 [f2fs]
>>> ? f2fs_submit_page_write+0x736/0x780 [f2fs]
>>> do_write_page+0x50/0x170 [f2fs]
>>> f2fs_outplace_write_data+0x61/0xb0 [f2fs]
>>> f2fs_do_write_data_page+0x3f8/0x660 [f2fs]
>>> f2fs_write_single_data_page+0x5bb/0x7a0 [f2fs]
>>> f2fs_write_cache_pages+0x3da/0xbe0 [f2fs]
>>> ...
>>> It is possible that other threads have added this fio to io->bio
>>> and submitted the io->bio before entering f2fs_submit_page_write().
>>> At this point io->bio = NULL.
>>> If is_end_zone_blkaddr(sbi, fio->new_blkaddr) of this fio is true,
>>> then an NULL pointer dereference error occurs at bio_get(io->bio).
>>> The original code for determining zone end was after "out:",
>>> which would have missed some fio who is zone end. I've moved
>>> this code before "skip:" to make sure it's done for each fio.
>>>
>>> Signed-off-by: Wenjie Qi <[email protected]>
>>> ---
>>> fs/f2fs/data.c | 8 ++++----
>>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index dce8defdf4c7..4f445906db8b 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -1080,10 +1080,6 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
>>> io->last_block_in_bio = fio->new_blkaddr;
>>>
>>> trace_f2fs_submit_page_write(fio->page, fio);
>>> -skip:
>>> - if (fio->in_list)
>>> - goto next;
>>> -out:
>>> #ifdef CONFIG_BLK_DEV_ZONED
>>> if (f2fs_sb_has_blkzoned(sbi) && btype < META &&
>>> is_end_zone_blkaddr(sbi, fio->new_blkaddr)) {
>>> @@ -1096,6 +1092,10 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
>>> __submit_merged_bio(io);
>>> }
>>> #endif
>>> +skip:
>>> + if (fio->in_list)
>>> + goto next;
>>> +out:
>>
>> How about moving only the "out" label instead of the whole block from
>> "skip" to "out"?
>>
>>> if (is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN) ||
>>> !f2fs_is_checkpoint_ready(sbi))
>>> __submit_merged_bio(io);
>>> --
>>> 2.34.1
>>>
>>>
>>>
>>> _______________________________________________
>>> Linux-f2fs-devel mailing list
>>> [email protected]
>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

2024-01-17 11:27:46

by Wenjie Qi

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH v1] f2fs: fix NULL pointer dereference in f2fs_submit_page_write()

Hello Yongpeng,
I don't think that's correct.
If list_empty(&io->io_list) and fio->in_list are true, it will jump to
the "out" label. This does not enter the judgment process.
In addition, __bio_alloc() will ensure that io->bio ! = NULL.

On Wed, Jan 17, 2024 at 6:17 PM Yongpeng Yang <[email protected]> wrote:
>
> Hello Wenjie,
> This patch does not prevent the simultaneous truth of
> list_empty(&io->io_list), fio->in_list, and is_end_zone_blkaddr(sbi,
> fio->new_blkaddr). NULL pointer dereference error still exists in
> “bio_get(io->bio)”. Is that correct?
>
> On 1/17/2024 9:39 AM, Wenjie Qi wrote:
> > Hello Daeho,
> > I don't think moving just the "out" label will work.
> > If a fio is zone end and in_list = 1, that fio is missed without being judged.
> >
> > On Wed, Jan 17, 2024 at 5:58 AM Daeho Jeong <[email protected]> wrote:
> >>
> >> On Tue, Jan 16, 2024 at 6:13 AM Wenjie Qi <[email protected]> wrote:
> >>>
> >>> BUG: kernel NULL pointer dereference, address: 0000000000000014
> >>> RIP: 0010:f2fs_submit_page_write+0x6cf/0x780 [f2fs]
> >>> Call Trace:
> >>> <TASK>
> >>> ? show_regs+0x6e/0x80
> >>> ? __die+0x29/0x70
> >>> ? page_fault_oops+0x154/0x4a0
> >>> ? prb_read_valid+0x20/0x30
> >>> ? __irq_work_queue_local+0x39/0xd0
> >>> ? irq_work_queue+0x36/0x70
> >>> ? do_user_addr_fault+0x314/0x6c0
> >>> ? exc_page_fault+0x7d/0x190
> >>> ? asm_exc_page_fault+0x2b/0x30
> >>> ? f2fs_submit_page_write+0x6cf/0x780 [f2fs]
> >>> ? f2fs_submit_page_write+0x736/0x780 [f2fs]
> >>> do_write_page+0x50/0x170 [f2fs]
> >>> f2fs_outplace_write_data+0x61/0xb0 [f2fs]
> >>> f2fs_do_write_data_page+0x3f8/0x660 [f2fs]
> >>> f2fs_write_single_data_page+0x5bb/0x7a0 [f2fs]
> >>> f2fs_write_cache_pages+0x3da/0xbe0 [f2fs]
> >>> ...
> >>> It is possible that other threads have added this fio to io->bio
> >>> and submitted the io->bio before entering f2fs_submit_page_write().
> >>> At this point io->bio = NULL.
> >>> If is_end_zone_blkaddr(sbi, fio->new_blkaddr) of this fio is true,
> >>> then an NULL pointer dereference error occurs at bio_get(io->bio).
> >>> The original code for determining zone end was after "out:",
> >>> which would have missed some fio who is zone end. I've moved
> >>> this code before "skip:" to make sure it's done for each fio.
> >>>
> >>> Signed-off-by: Wenjie Qi <[email protected]>
> >>> ---
> >>> fs/f2fs/data.c | 8 ++++----
> >>> 1 file changed, 4 insertions(+), 4 deletions(-)
> >>>
> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> >>> index dce8defdf4c7..4f445906db8b 100644
> >>> --- a/fs/f2fs/data.c
> >>> +++ b/fs/f2fs/data.c
> >>> @@ -1080,10 +1080,6 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> >>> io->last_block_in_bio = fio->new_blkaddr;
> >>>
> >>> trace_f2fs_submit_page_write(fio->page, fio);
> >>> -skip:
> >>> - if (fio->in_list)
> >>> - goto next;
> >>> -out:
> >>> #ifdef CONFIG_BLK_DEV_ZONED
> >>> if (f2fs_sb_has_blkzoned(sbi) && btype < META &&
> >>> is_end_zone_blkaddr(sbi, fio->new_blkaddr)) {
> >>> @@ -1096,6 +1092,10 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> >>> __submit_merged_bio(io);
> >>> }
> >>> #endif
> >>> +skip:
> >>> + if (fio->in_list)
> >>> + goto next;
> >>> +out:
> >>
> >> How about moving only the "out" label instead of the whole block from
> >> "skip" to "out"?
> >>
> >>> if (is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN) ||
> >>> !f2fs_is_checkpoint_ready(sbi))
> >>> __submit_merged_bio(io);
> >>> --
> >>> 2.34.1
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> Linux-f2fs-devel mailing list
> >>> [email protected]
> >>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> >
> >
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel