[PATCH xserver] loader: Handle mod->VersionInfo == NULL

[Peter Hutterer]

On Thu, Jan 26, 2017 at 04:24:03PM +0900, Michel Dänzer wrote:
> From: Michel Dänzer <michel.daenzer at amd.com>
> 
> This can happen when a module fails to load:
> 
> Program received signal SIGSEGV, Segmentation fault.
> UnloadModule (_mod=0x5555559d9280) at ../../../../hw/xfree86/loader/loadmod.c:848
> 848	    name = mod->VersionInfo->modname;
> (gdb) bt
> #0  UnloadModule (_mod=0x5555559d9280) at ../../../../hw/xfree86/loader/loadmod.c:848
> #1  0x00005555555ddd1b in LoadModule (module=module at entry=0x5555559c7ce0 "fbdev", options=0x0, modreq=modreq at entry=0x0, errmaj=errmaj at entry=0x7fffffffe8ec) at ../../../../hw/xfree86/loader/loadmod.c:824
> #2  0x00005555555edfe9 in xf86LoadModules (list=list at entry=0x5555559dcf50, optlist=optlist at entry=0x0) at ../../../../hw/xfree86/common/xf86Init.c:1506
> #3  0x00005555555ee7bc in InitOutput (pScreenInfo=pScreenInfo at entry=0x5555559abf80 <screenInfo>, argc=argc at entry=4, argv=argv at entry=0x7fffffffeb18) at ../../../../hw/xfree86/common/xf86Init.c:484
> #4  0x00005555555a885c in dix_main (argc=4, argv=0x7fffffffeb18, envp=<optimized out>) at ../../dix/main.c:197
> #5  0x00007ffff5d582b1 in __libc_start_main (main=0x555555593130 <main>, argc=4, argv=0x7fffffffeb18, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffeb08) at ../csu/libc-start.c:291
> #6  0x000055555559316a in _start ()
> 
> Fixes: 8e83eacb9e2d ("loader: Remove unused path and name from ModuleDescPtr")
> Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>

Thanks, ran into this one today too :)

remote: Updating patchwork state for https://patchwork.freedesktop.org/project/Xorg/list/
remote: I: patch #135413 updated using rev 45e0eb4b156f2155687cce268b07f10540fc507b.
remote: I: 1 patch(es) updated to state Accepted.
To git+ssh://git.freedesktop.org/git/xorg/xserver
   7617a0a..45e0eb4  master -> master

Cheers,
   Peter

> ---
>  hw/xfree86/loader/loadmod.c | 21 +++++++++++----------
>  1 file changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/xfree86/loader/loadmod.c b/hw/xfree86/loader/loadmod.c
> index ca77c7a9d..09aae0ea2 100644
> --- a/hw/xfree86/loader/loadmod.c
> +++ b/hw/xfree86/loader/loadmod.c
> @@ -837,7 +837,6 @@ void
>  UnloadModule(void *_mod)
>  {
>      ModuleDescPtr mod = _mod;
> -    const char *name;
>  
>      if (mod == (ModuleDescPtr) 1)
>          return;
> @@ -845,17 +844,19 @@ UnloadModule(void *_mod)
>      if (mod == NULL)
>          return;
>  
> -    name = mod->VersionInfo->modname;
> +    if (mod->VersionInfo) {
> +        const char *name = mod->VersionInfo->modname;
>  
> -    if (mod->parent)
> -        LogMessageVerbSigSafe(X_INFO, 3, "UnloadSubModule: \"%s\"\n", name);
> -    else
> -        LogMessageVerbSigSafe(X_INFO, 3, "UnloadModule: \"%s\"\n", name);
> +        if (mod->parent)
> +            LogMessageVerbSigSafe(X_INFO, 3, "UnloadSubModule: \"%s\"\n", name);
> +        else
> +            LogMessageVerbSigSafe(X_INFO, 3, "UnloadModule: \"%s\"\n", name);
>  
> -    if (mod->TearDownData != ModuleDuplicated) {
> -        if ((mod->TearDownProc) && (mod->TearDownData))
> -            mod->TearDownProc(mod->TearDownData);
> -        LoaderUnload(name, mod->handle);
> +        if (mod->TearDownData != ModuleDuplicated) {
> +            if ((mod->TearDownProc) && (mod->TearDownData))
> +                mod->TearDownProc(mod->TearDownData);
> +            LoaderUnload(name, mod->handle);
> +        }
>      }
>  
>      if (mod->child)
> -- 
> 2.11.0
> 
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