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* [Qemu-devel] [PATCH] linux-user: assert that target_mprotect cannot fail
@ 2015-09-14 10:31 Paolo Bonzini
  2015-10-01  8:46 ` Riku Voipio
  0 siblings, 1 reply; 2+ messages in thread
From: Paolo Bonzini @ 2015-09-14 10:31 UTC (permalink / raw)
  To: qemu-devel; +Cc: riku.voipio

All error conditions that target_mprotect checks are also checked
by target_mmap.  EACCESS cannot happen because we are just removing
PROT_WRITE.  ENOMEM should not happen because we are modifying a
whole VMA (and we have bigger problems anyway if it happens).

Fixes a Coverity false positive, where Coverity complains about
target_mprotect's return value being passed to tb_invalidate_phys_range.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 linux-user/mmap.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index b2126c7..5606bcd 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -514,10 +514,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
                 goto fail;
             if (!(prot & PROT_WRITE)) {
                 ret = target_mprotect(start, len, prot);
-                if (ret != 0) {
-                    start = ret;
-                    goto the_end;
-                }
+                assert(ret == 0);
             }
             goto the_end;
         }
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [Qemu-devel] [PATCH] linux-user: assert that target_mprotect cannot fail
  2015-09-14 10:31 [Qemu-devel] [PATCH] linux-user: assert that target_mprotect cannot fail Paolo Bonzini
@ 2015-10-01  8:46 ` Riku Voipio
  0 siblings, 0 replies; 2+ messages in thread
From: Riku Voipio @ 2015-10-01  8:46 UTC (permalink / raw)
  To: Paolo Bonzini; +Cc: qemu-devel

On Mon, Sep 14, 2015 at 12:31:44PM +0200, Paolo Bonzini wrote:
> All error conditions that target_mprotect checks are also checked
> by target_mmap.  EACCESS cannot happen because we are just removing
> PROT_WRITE.  ENOMEM should not happen because we are modifying a
> whole VMA (and we have bigger problems anyway if it happens).
> 
> Fixes a Coverity false positive, where Coverity complains about
> target_mprotect's return value being passed to tb_invalidate_phys_range.

Applied to linux-user, thanks

> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  linux-user/mmap.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/linux-user/mmap.c b/linux-user/mmap.c
> index b2126c7..5606bcd 100644
> --- a/linux-user/mmap.c
> +++ b/linux-user/mmap.c
> @@ -514,10 +514,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
>                  goto fail;
>              if (!(prot & PROT_WRITE)) {
>                  ret = target_mprotect(start, len, prot);
> -                if (ret != 0) {
> -                    start = ret;
> -                    goto the_end;
> -                }
> +                assert(ret == 0);
>              }
>              goto the_end;
>          }
> -- 
> 2.5.0
> 
> 

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2015-09-14 10:31 [Qemu-devel] [PATCH] linux-user: assert that target_mprotect cannot fail Paolo Bonzini
2015-10-01  8:46 ` Riku Voipio

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