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From: Zhiguo Niu <niuzhiguo84@gmail.com>
Date: Tue, 6 Feb 2024 13:58:04 +0800
Message-ID: <CAHJ8P3KVJvNfPhUa07j87irmbjgV8nsuCby2oASTM=QHboWc2A@mail.gmail.com>
Subject: Re: [PATCH 0/3] f2fs: fix panic issue in small capacity device
To: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Zhiguo Niu <zhiguo.niu@unisoc.com>, chao@kernel.org, 
	linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, 
	ke.wang@unisoc.com, hongyu.jin@unisoc.com
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On Tue, Feb 6, 2024 at 11:15=E2=80=AFAM Jaegeuk Kim <jaegeuk@kernel.org> wr=
ote:
>
> On 01/29, Zhiguo Niu wrote:
> > A panic issue happened in a reboot test in small capacity device
> > as following:
> > 1.The device size is 64MB, and main area has 24 segments, and
> > CONFIG_F2FS_CHECK_FS is not enabled.
> > 2.There is no any free segments left shown in free_segmap_info,
> > then another write request cause get_new_segment get a out-of-bound
> > segment with segno 24.
> > 3.panic happen in update_sit_entry because access invalid bitmap
> > pointer.
>
> The goal here is to stop f2fs when it hits no space to write anymore?
Do not let the system crash now , and add some sanity check to avoid
accessing  illegal memory
> And, we need f2fs_stop_checkpoint() at the end?
I think it need indeed.
thanks!
>
> >
> > More detail shown in following three patches.
> > The three patches are splited here because the modifications are
> > relatively independent and more readable.
> >
> > Zhiguo Niu (3):
> >   f2fs: correct counting methods of free_segments in __set_inuse
> >   f2fs: fix panic issue in update_sit_entry
> >   f2fs: enhance judgment conditions of GET_SEGNO
> >
> >  fs/f2fs/file.c    | 7 ++++++-
> >  fs/f2fs/segment.c | 9 ++++++---
> >  fs/f2fs/segment.h | 7 ++++---
> >  3 files changed, 16 insertions(+), 7 deletions(-)
> >
> > --
> > 1.9.1