Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-25 05:32:00 +00:00
Code Issues Packages Projects Releases Wiki Activity

livepatch: Reorder to use before freeing a pointer

Browse Source 
Clang static analysis reports this issue
livepatch-shadow-fix1.c:113:2: warning: Use of
  memory after it is freed
  pr_info("%s: dummy @ %p, prevented leak @ %p\n",
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The pointer is freed in the previous statement.
Reorder the pr_info to report before the free.

Similar issue in livepatch-shadow-fix2.c

Note that it is a false positive. pr_info() just prints the address.
The freed memory is not accessed. Well, the static analyzer could not
know this easily.

Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: David Vernet <void@manifault.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
[pmladek@suse.com: Note about that it was false positive.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220320015143.2208591-1-trix@redhat.com
This commit is contained in:
Tom Rix 2022-03-19 18:51:43 -07:00 committed by Petr Mladek
parent 4327b9eaf8
commit 5e6ded2e7a
2 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
samples/livepatch/livepatch-shadow-fix1.c
View File

@ -109,9 +109,9 @@ static void livepatch_fix1_dummy_leak_dtor(void *obj, void *shadow_data)
void *d = obj; void *d = obj;
int **shadow_leak = shadow_data; int **shadow_leak = shadow_data;
kfree(*shadow_leak);
pr_info("%s: dummy @ %p, prevented leak @ %p\n", pr_info("%s: dummy @ %p, prevented leak @ %p\n",
__func__, d, *shadow_leak); __func__, d, *shadow_leak);
kfree(*shadow_leak);
} }
static void livepatch_fix1_dummy_free(struct dummy *d) static void livepatch_fix1_dummy_free(struct dummy *d)

2
samples/livepatch/livepatch-shadow-fix2.c
View File

@ -61,9 +61,9 @@ static void livepatch_fix2_dummy_leak_dtor(void *obj, void *shadow_data)
void *d = obj; void *d = obj;
int **shadow_leak = shadow_data; int **shadow_leak = shadow_data;
kfree(*shadow_leak);
pr_info("%s: dummy @ %p, prevented leak @ %p\n", pr_info("%s: dummy @ %p, prevented leak @ %p\n",
__func__, d, *shadow_leak); __func__, d, *shadow_leak);
kfree(*shadow_leak);
} }
static void livepatch_fix2_dummy_free(struct dummy *d) static void livepatch_fix2_dummy_free(struct dummy *d)