diff mbox series

[v2,9/9] bsd-user/mmap.c: assert that target_mprotect cannot fail

Message ID 20210922045636.25206-10-imp@bsdimp.com
State New
Headers show
Series bsd-user mmap fixes | expand

Commit Message

Warner Losh Sept. 22, 2021, 4:56 a.m. UTC 
Similar to the equivalent linux-user change 86abac06c14. 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: Mikaël Urankar <mikael.urankar@gmail.com>
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
 bsd-user/mmap.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

Comments

Richard Henderson Sept. 23, 2021, 5:53 p.m. UTC | #1 
On 9/21/21 9:56 PM, Warner Losh wrote:
> Similar to the equivalent linux-user change 86abac06c14. 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: Mikaël Urankar<mikael.urankar@gmail.com>
> Signed-off-by: Warner Losh<imp@bsdimp.com>
> ---
>   bsd-user/mmap.c | 5 +----
>   1 file changed, 1 insertion(+), 4 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~
Philippe Mathieu-Daudé Sept. 25, 2021, 10:58 a.m. UTC | #2 
On 9/22/21 06:56, Warner Losh wrote:
> Similar to the equivalent linux-user change 86abac06c14. 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: Mikaël Urankar <mikael.urankar@gmail.com>
> Signed-off-by: Warner Losh <imp@bsdimp.com>
> ---
>   bsd-user/mmap.c | 5 +----
>   1 file changed, 1 insertion(+), 4 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
diff mbox series

Patch

diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index 792ff00548..4ddbd50b62 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -591,10 +591,7 @@  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;
         }