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

[Chao Yu]

On 2024/1/29 18:27, Chao Yu wrote:
> On 2024/1/16 22:11, Wenjie Qi 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.

Fixes: e067dc3c6b9c ("f2fs: maintain six open zones for zoned devices")

> > Signed-off-by: Wenjie Qi <qwjhust@xxxxxxxxx>
>
> Reviewed-by: Chao Yu <chao@xxxxxxxxxx>
>
> Thanks,
>
>
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