* [PATCH] malloc: preserve errno on mcheck hooks [BZ #17924]
@ 2020-12-29 20:24 Adhemerval Zanella
2020-12-29 21:11 ` H.J. Lu
2020-12-29 21:12 ` Paul Eggert
0 siblings, 2 replies; 3+ messages in thread
From: Adhemerval Zanella @ 2020-12-29 20:24 UTC (permalink / raw)
To: libc-alpha, Paul Eggert
Similar to the fix 69fda43b8d, save and restore errno for the hook
functions used for MALLOC_CHECK_=3.
It fixes the malloc/tst-free-errno-mcheck regression.
Checked on x86_64-linux-gnu.
---
malloc/hooks.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/malloc/hooks.c b/malloc/hooks.c
index 6474ba8b38..fc285f15c6 100644
--- a/malloc/hooks.c
+++ b/malloc/hooks.c
@@ -260,6 +260,8 @@ free_check (void *mem, const void *caller)
if (!mem)
return;
+ int err = errno;
+
#ifdef USE_MTAG
/* Quickly check that the freed pointer matches the tag for the memory.
This gives a useful double-free detection. */
@@ -274,12 +276,16 @@ free_check (void *mem, const void *caller)
{
__libc_lock_unlock (main_arena.mutex);
munmap_chunk (p);
- return;
}
- /* Mark the chunk as belonging to the library again. */
- (void)TAG_REGION (chunk2rawmem (p), CHUNK_AVAILABLE_SIZE (p) - CHUNK_HDR_SZ);
- _int_free (&main_arena, p, 1);
- __libc_lock_unlock (main_arena.mutex);
+ else
+ {
+ /* Mark the chunk as belonging to the library again. */
+ (void)TAG_REGION (chunk2rawmem (p), CHUNK_AVAILABLE_SIZE (p)
+ - CHUNK_HDR_SZ);
+ _int_free (&main_arena, p, 1);
+ __libc_lock_unlock (main_arena.mutex);
+ }
+ __set_errno (err);
}
static void *
--
2.25.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] malloc: preserve errno on mcheck hooks [BZ #17924]
2020-12-29 20:24 [PATCH] malloc: preserve errno on mcheck hooks [BZ #17924] Adhemerval Zanella
@ 2020-12-29 21:11 ` H.J. Lu
2020-12-29 21:12 ` Paul Eggert
1 sibling, 0 replies; 3+ messages in thread
From: H.J. Lu @ 2020-12-29 21:11 UTC (permalink / raw)
To: Adhemerval Zanella; +Cc: GNU C Library, Paul Eggert
On Tue, Dec 29, 2020 at 12:24 PM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
> Similar to the fix 69fda43b8d, save and restore errno for the hook
> functions used for MALLOC_CHECK_=3.
>
> It fixes the malloc/tst-free-errno-mcheck regression.
>
> Checked on x86_64-linux-gnu.
> ---
> malloc/hooks.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/malloc/hooks.c b/malloc/hooks.c
> index 6474ba8b38..fc285f15c6 100644
> --- a/malloc/hooks.c
> +++ b/malloc/hooks.c
> @@ -260,6 +260,8 @@ free_check (void *mem, const void *caller)
> if (!mem)
> return;
>
> + int err = errno;
> +
> #ifdef USE_MTAG
> /* Quickly check that the freed pointer matches the tag for the memory.
> This gives a useful double-free detection. */
> @@ -274,12 +276,16 @@ free_check (void *mem, const void *caller)
> {
> __libc_lock_unlock (main_arena.mutex);
> munmap_chunk (p);
> - return;
> }
> - /* Mark the chunk as belonging to the library again. */
> - (void)TAG_REGION (chunk2rawmem (p), CHUNK_AVAILABLE_SIZE (p) - CHUNK_HDR_SZ);
> - _int_free (&main_arena, p, 1);
> - __libc_lock_unlock (main_arena.mutex);
> + else
> + {
> + /* Mark the chunk as belonging to the library again. */
> + (void)TAG_REGION (chunk2rawmem (p), CHUNK_AVAILABLE_SIZE (p)
> + - CHUNK_HDR_SZ);
> + _int_free (&main_arena, p, 1);
> + __libc_lock_unlock (main_arena.mutex);
> + }
> + __set_errno (err);
> }
>
> static void *
> --
> 2.25.1
>
LGTM.
Thanks.
--
H.J.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] malloc: preserve errno on mcheck hooks [BZ #17924]
2020-12-29 20:24 [PATCH] malloc: preserve errno on mcheck hooks [BZ #17924] Adhemerval Zanella
2020-12-29 21:11 ` H.J. Lu
@ 2020-12-29 21:12 ` Paul Eggert
1 sibling, 0 replies; 3+ messages in thread
From: Paul Eggert @ 2020-12-29 21:12 UTC (permalink / raw)
To: Adhemerval Zanella, libc-alpha
On 12/29/20 12:24 PM, Adhemerval Zanella wrote:
> Similar to the fix 69fda43b8d, save and restore errno for the hook
> functions used for MALLOC_CHECK_=3.
>
> It fixes the malloc/tst-free-errno-mcheck regression.
Thanks, this patch looks good to me.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-12-29 20:24 [PATCH] malloc: preserve errno on mcheck hooks [BZ #17924] Adhemerval Zanella
2020-12-29 21:11 ` H.J. Lu
2020-12-29 21:12 ` Paul Eggert
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