[PATCH] libxcmd: add return value check for dynamic memory function

[PATCH] libxcmd: add return value check for dynamic memory function

[Weifeng Su]

The result check was missed and It cause the coredump like:
0x00005589f3e358dd in add_command (ci=0x5589f3e3f020 <health_cmd>) at command.c:37
0x00005589f3e337d8 in init_commands () at init.c:37
init (argc=<optimized out>, argv=0x7ffecfb0cd28) at init.c:102
0x00005589f3e33399 in main (argc=<optimized out>, argv=<optimized out>) at init.c:112

Add check for realloc function to ignore this coredump and exit with
error output

Signed-off-by: Weifeng Su <suweifeng1@huawei.com>
---
 libxcmd/command.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libxcmd/command.c b/libxcmd/command.c
index a76d1515..47d050c3 100644
--- a/libxcmd/command.c
+++ b/libxcmd/command.c
@@ -34,6 +34,10 @@ add_command(
 	const cmdinfo_t	*ci)
 {
 	cmdtab = realloc((void *)cmdtab, ++ncmds * sizeof(*cmdtab));
+	if (!cmdtab) {
+		perror("realloc");
+		exit(1);
+	}
 	cmdtab[ncmds - 1] = *ci;
 	qsort(cmdtab, ncmds, sizeof(*cmdtab), compare);
 }
-- 
2.18.0.windows.1

Re: [PATCH] libxcmd: add return value check for dynamic memory function

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH] libxcmd: add return value check for dynamic memory function

[Darrick J. Wong]

On Wed, Jun 07, 2023 at 05:30:18PM +0800, Weifeng Su wrote:
> The result check was missed and It cause the coredump like:
> 0x00005589f3e358dd in add_command (ci=0x5589f3e3f020 <health_cmd>) at command.c:37
> 0x00005589f3e337d8 in init_commands () at init.c:37
> init (argc=<optimized out>, argv=0x7ffecfb0cd28) at init.c:102
> 0x00005589f3e33399 in main (argc=<optimized out>, argv=<optimized out>) at init.c:112
> 
> Add check for realloc function to ignore this coredump and exit with
> error output
> 
> Signed-off-by: Weifeng Su <suweifeng1@huawei.com>
> ---
>  libxcmd/command.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/libxcmd/command.c b/libxcmd/command.c
> index a76d1515..47d050c3 100644
> --- a/libxcmd/command.c
> +++ b/libxcmd/command.c
> @@ -34,6 +34,10 @@ add_command(
>  	const cmdinfo_t	*ci)
>  {
>  	cmdtab = realloc((void *)cmdtab, ++ncmds * sizeof(*cmdtab));
> +	if (!cmdtab) {
> +		perror("realloc");

The string argument should be more descriptive of /where/ we failed.

	"realloc: Out of memory"

Tells us what failed, but not where; and we could probably figure that
out from strace data.

	if (!cmdtab)
		perror("add_command");

	"add_command: Out of memory"

is better at implying that the triager should look for a function named
add_command and start there.  You could even go as far as:

	if (!cmdtab)
		perror(_("adding libxcmd command"));

	"adding libxcmd command: Out of memory"

which gives us a nice long string to grep.

--D

> +		exit(1);
> +	}
>  	cmdtab[ncmds - 1] = *ci;
>  	qsort(cmdtab, ncmds, sizeof(*cmdtab), compare);
>  }
> -- 
> 2.18.0.windows.1
>