[PATCH] jffs2: fix use of uninitialized variable

[PATCH] jffs2: fix use of uninitialized variable

[Qingfang Deng]

From: Qingfang Deng <qingfang.deng@siflower.com.cn>

When building the kernel with -Wmaybe-uninitialized, the compiler
reports this warning:

In function 'jffs2_mark_erased_block',
    inlined from 'jffs2_erase_pending_blocks' at fs/jffs2/erase.c:116:4:
fs/jffs2/erase.c:474:9: warning: 'bad_offset' may be used uninitialized [-Wmaybe-uninitialized]
  474 |         jffs2_erase_failed(c, jeb, bad_offset);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/jffs2/erase.c: In function 'jffs2_erase_pending_blocks':
fs/jffs2/erase.c:402:18: note: 'bad_offset' was declared here
  402 |         uint32_t bad_offset;
      |                  ^~~~~~~~~~

When mtd->point() is used, jffs2_erase_pending_blocks can return -EIO
without initializing bad_offset, which is later used at the filebad
label in jffs2_mark_erased_block.
Fix it by initializing this variable.

Fixes: 8a0f572397ca ("[JFFS2] Return values of jffs2_block_check_erase error paths")
Signed-off-by: Qingfang Deng <qingfang.deng@siflower.com.cn>
---
 fs/jffs2/erase.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/jffs2/erase.c b/fs/jffs2/erase.c
index acd32f05b519..ef3a1e1b6cb0 100644
--- a/fs/jffs2/erase.c
+++ b/fs/jffs2/erase.c
@@ -338,10 +338,9 @@ static int jffs2_block_check_erase(struct jffs2_sb_info *c, struct jffs2_erasebl
 		} while(--retlen);
 		mtd_unpoint(c->mtd, jeb->offset, c->sector_size);
 		if (retlen) {
-			pr_warn("Newly-erased block contained word 0x%lx at offset 0x%08tx\n",
-				*wordebuf,
-				jeb->offset +
-				c->sector_size-retlen * sizeof(*wordebuf));
+			*bad_offset = jeb->offset + c->sector_size - retlen * sizeof(*wordebuf);
+			pr_warn("Newly-erased block contained word 0x%lx at offset 0x%08x\n",
+				*wordebuf, *bad_offset);
 			return -EIO;
 		}
 		return 0;
-- 
2.34.1

Re: [PATCH] jffs2: fix use of uninitialized variable

[Zhihao Cheng]

在 2024/7/1 12:52, Qingfang Deng 写道:
> From: Qingfang Deng <qingfang.deng@siflower.com.cn>
> 
> When building the kernel with -Wmaybe-uninitialized, the compiler
> reports this warning:
> 
> In function 'jffs2_mark_erased_block',
>      inlined from 'jffs2_erase_pending_blocks' at fs/jffs2/erase.c:116:4:
> fs/jffs2/erase.c:474:9: warning: 'bad_offset' may be used uninitialized [-Wmaybe-uninitialized]
>    474 |         jffs2_erase_failed(c, jeb, bad_offset);
>        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> fs/jffs2/erase.c: In function 'jffs2_erase_pending_blocks':
> fs/jffs2/erase.c:402:18: note: 'bad_offset' was declared here
>    402 |         uint32_t bad_offset;
>        |                  ^~~~~~~~~~
> 
> When mtd->point() is used, jffs2_erase_pending_blocks can return -EIO
> without initializing bad_offset, which is later used at the filebad
> label in jffs2_mark_erased_block.
> Fix it by initializing this variable.
> 
> Fixes: 8a0f572397ca ("[JFFS2] Return values of jffs2_block_check_erase error paths")
> Signed-off-by: Qingfang Deng <qingfang.deng@siflower.com.cn>
> ---
>   fs/jffs2/erase.c | 7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
> 
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
> diff --git a/fs/jffs2/erase.c b/fs/jffs2/erase.c
> index acd32f05b519..ef3a1e1b6cb0 100644
> --- a/fs/jffs2/erase.c
> +++ b/fs/jffs2/erase.c
> @@ -338,10 +338,9 @@ static int jffs2_block_check_erase(struct jffs2_sb_info *c, struct jffs2_erasebl
>   		} while(--retlen);
>   		mtd_unpoint(c->mtd, jeb->offset, c->sector_size);
>   		if (retlen) {
> -			pr_warn("Newly-erased block contained word 0x%lx at offset 0x%08tx\n",
> -				*wordebuf,
> -				jeb->offset +
> -				c->sector_size-retlen * sizeof(*wordebuf));
> +			*bad_offset = jeb->offset + c->sector_size - retlen * sizeof(*wordebuf);
> +			pr_warn("Newly-erased block contained word 0x%lx at offset 0x%08x\n",
> +				*wordebuf, *bad_offset);
>   			return -EIO;
>   		}
>   		return 0;
> 

Re: [PATCH] jffs2: fix use of uninitialized variable

[Qingfang Deng]

Any update on this?

Re: [PATCH] jffs2: fix use of uninitialized variable

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "Qingfang Deng" <dqfext@gmail.com>
> An: "David Woodhouse" <dwmw2@infradead.org>, "richard" <richard@nod.at>, "Qingfang Deng"
> <qingfang.deng@siflower.com.cn>, "linux-mtd" <linux-mtd@lists.infradead.org>, "linux-kernel"
> <linux-kernel@vger.kernel.org>
> Gesendet: Dienstag, 12. November 2024 06:46:51
> Betreff: Re: [PATCH] jffs2: fix use of uninitialized variable

> Any update on this?

It's planned for the upcomming merge window.

Thanks,
//richard