diff mbox series

[v2,03/14] elf: Fix comments and logic in _dl_add_to_slotinfo

Message ID 6b63f027658b2bbe41f2da374da0aff63a77647f.1618301209.git.szabolcs.nagy@arm.com
State Committed
Commit c489c35054c39d7f2437ca61b369e3ede448f022
Delegated to: Adhemerval Zanella Netto
Headers
Series Dynamic TLS related data race fixes |

Commit Message

Szabolcs Nagy April 13, 2021, 8:18 a.m. UTC 
  Since

  commit a509eb117fac1d764b15eba64993f4bdb63d7f3c
  Avoid late dlopen failure due to scope, TLS slotinfo updates [BZ #25112]

the generation counter update is not needed in the failure path.
That commit ensures allocation in _dl_add_to_slotinfo happens before
the demarcation point in dlopen (it is called twice, first time is for
allocation only where dlopen can still be reverted on failure, then
second time actual dtv updates are done which then cannot fail).

--
v2:
- expanded the commit message a bit.
---
 elf/dl-tls.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

Comments

Adhemerval Zanella Netto April 14, 2021, 6:12 p.m. UTC | #1 
On 13/04/2021 05:18, Szabolcs Nagy via Libc-alpha wrote:
> Since
> 
>   commit a509eb117fac1d764b15eba64993f4bdb63d7f3c
>   Avoid late dlopen failure due to scope, TLS slotinfo updates [BZ #25112]
> 
> the generation counter update is not needed in the failure path.
> That commit ensures allocation in _dl_add_to_slotinfo happens before
> the demarcation point in dlopen (it is called twice, first time is for
> allocation only where dlopen can still be reverted on failure, then
> second time actual dtv updates are done which then cannot fail).


LGTM, the commit is more clear now.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> 
> --
> v2:
> - expanded the commit message a bit.
> ---
>  elf/dl-tls.c | 11 +----------
>  1 file changed, 1 insertion(+), 10 deletions(-)
> 
> diff --git a/elf/dl-tls.c b/elf/dl-tls.c
> index 79b93ad91b..24d00c14ef 100644
> --- a/elf/dl-tls.c
> +++ b/elf/dl-tls.c
> @@ -998,16 +998,7 @@ _dl_add_to_slotinfo (struct link_map *l, bool do_add)
>  		+ TLS_SLOTINFO_SURPLUS * sizeof (struct dtv_slotinfo));
>        if (listp == NULL)
>  	{
> -	  /* We ran out of memory.  We will simply fail this
> -	     call but don't undo anything we did so far.  The
> -	     application will crash or be terminated anyway very
> -	     soon.  */
> -
> -	  /* We have to do this since some entries in the dtv
> -	     slotinfo array might already point to this
> -	     generation.  */
> -	  ++GL(dl_tls_generation);
> -
> +	  /* We ran out of memory while resizing the dtv slotinfo list.  */
>  	  _dl_signal_error (ENOMEM, "dlopen", NULL, N_("\
>  cannot create TLS data structures"));
>  	}
>
diff mbox series

Patch

diff --git a/elf/dl-tls.c b/elf/dl-tls.c
index 79b93ad91b..24d00c14ef 100644
--- a/elf/dl-tls.c
+++ b/elf/dl-tls.c
@@ -998,16 +998,7 @@  _dl_add_to_slotinfo (struct link_map *l, bool do_add)
 		+ TLS_SLOTINFO_SURPLUS * sizeof (struct dtv_slotinfo));
       if (listp == NULL)
 	{
-	  /* We ran out of memory.  We will simply fail this
-	     call but don't undo anything we did so far.  The
-	     application will crash or be terminated anyway very
-	     soon.  */
-
-	  /* We have to do this since some entries in the dtv
-	     slotinfo array might already point to this
-	     generation.  */
-	  ++GL(dl_tls_generation);
-
+	  /* We ran out of memory while resizing the dtv slotinfo list.  */
 	  _dl_signal_error (ENOMEM, "dlopen", NULL, N_("\
 cannot create TLS data structures"));
 	}