| Message ID | 20250121150617.608118-1-eugen.hristev@linaro.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | pstore/zone: fix return value for psz_init_zones | expand |
On 1/21/25 17:06, Eugen Hristev wrote: > psz_init_zones is not supposed to return NULL. It returns an errno, > and its caller always checks for an errno to look for a problem. > If the caller receives a NULL as a return, this code will go further > without any errors: > > cxt->kpszs = psz_init_zones(PSTORE_TYPE_DMESG, &off, > info->total_size - off_size, > info->kmsg_size, &cxt->kmsg_max_cnt); > if (IS_ERR(cxt->kpszs)) { > err = PTR_ERR(cxt->kpszs); > cxt->kpszs = NULL; > goto free_out; > } > > Later, when dereferencing kpszs, a panic would occur. > > Thus, to avoid this possible crash, it's better to avoid returning NULL > in psz_init_zones, and just return -EINVAL if the parameters received > are wrong (in this case, a zero size request). Please disregard this patch. I found a case when NULL is being used meaningfully so I have to find a better way to handle this. Sorry for the noise.
diff --git a/fs/pstore/zone.c b/fs/pstore/zone.c index 5fa2fa2e7aa7..dbafc72a2f68 100644 --- a/fs/pstore/zone.c +++ b/fs/pstore/zone.c @@ -1204,7 +1204,7 @@ static struct pstore_zone **psz_init_zones(enum pstore_type_id type, *cnt = 0; if (!total_size || !record_size) - return NULL; + return ERR_PTR(-EINVAL); if (*off + total_size > info->total_size) { pr_err("no room for zones %s (0x%zx@0x%llx over 0x%lx)\n",
psz_init_zones is not supposed to return NULL. It returns an errno, and its caller always checks for an errno to look for a problem. If the caller receives a NULL as a return, this code will go further without any errors: cxt->kpszs = psz_init_zones(PSTORE_TYPE_DMESG, &off, info->total_size - off_size, info->kmsg_size, &cxt->kmsg_max_cnt); if (IS_ERR(cxt->kpszs)) { err = PTR_ERR(cxt->kpszs); cxt->kpszs = NULL; goto free_out; } Later, when dereferencing kpszs, a panic would occur. Thus, to avoid this possible crash, it's better to avoid returning NULL in psz_init_zones, and just return -EINVAL if the parameters received are wrong (in this case, a zero size request). Fixes: d26c3321fe18 ("pstore/zone: Introduce common layer to manage storage zones") Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org> --- fs/pstore/zone.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)