From: Stefan Lippers-Hollmann Date: Tue, 6 Apr 2010 21:45:38 +0000 (+0200) Subject: drm/radeon/kms: Fix NULL pointer dereference if memory allocation failed in a simple way X-Git-Tag: v2.6.33.3~132 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=7cf84e3ccb91a9e5b2c4fe25ec6a3a79f0e24f98;p=karo-tx-linux.git drm/radeon/kms: Fix NULL pointer dereference if memory allocation failed in a simple way > From: Pauli Nieminen > Date: Fri, 19 Mar 2010 07:44:33 +0000 > Subject: drm/radeon/kms: Fix NULL pointer dereference if memory allocation failed. > > From: Pauli Nieminen > > commit fcbc451ba1948fba967198bd150ecbd10bbb7075 upstream. > > When there is allocation failure in radeon_cs_parser_relocs parser->nrelocs > is not cleaned. This causes NULL pointer defeference in radeon_cs_parser_fini > when clean up code is trying to loop over the relocation array and free the > objects. > > Fix adds a check for a possible NULL pointer in clean up code. [...] This patch breaks compiling kernel 2.6.33 + the current stable queue: CC [M] drivers/gpu/drm/radeon/radeon_cs.o /tmp/buildd/linux-sidux-2.6-2.6.33/debian/build/source_amd64_none/drivers/gpu/drm/radeon/radeon_cs.c: In function 'radeon_cs_parser_fini': /tmp/buildd/linux-sidux-2.6-2.6.33/debian/build/source_amd64_none/drivers/gpu/drm/radeon/radeon_cs.c:200: error: implicit declaration of function 'drm_gem_object_unreference_unlocked' make[6]: *** [drivers/gpu/drm/radeon/radeon_cs.o] Error 1 as it depends on the introduction of drm_gem_object_unreference_unlocked() in: Commit: c3ae90c099bb62387507e86da7cf799850444b08 Author: Luca Barbieri AuthorDate: Tue Feb 9 05:49:11 2010 +0000 drm: introduce drm_gem_object_[handle_]unreference_unlocked This patch introduces the drm_gem_object_unreference_unlocked and drm_gem_object_handle_unreference_unlocked functions that do not require holding struct_mutex. drm_gem_object_unreference_unlocked calls the new ->gem_free_object_unlocked entry point if available, and otherwise just takes struct_mutex and just calls ->gem_free_object which in turn suggests: Commit: bc9025bdc4e2b591734cca17697093845007b63d Author: Luca Barbieri AuthorDate: Tue Feb 9 05:49:12 2010 +0000 Use drm_gem_object_[handle_]unreference_unlocked where possible Mostly obvious simplifications. The i915 pread/pwrite ioctls, intel_overlay_put_image and nouveau_gem_new were incorrectly using the locked versions without locking: this is also fixed in this patch. which don't really look like candidates for 2.6.33-stable. > --- a/drivers/gpu/drm/radeon/radeon_cs.c > +++ b/drivers/gpu/drm/radeon/radeon_cs.c > @@ -193,11 +193,13 @@ static void radeon_cs_parser_fini(struct > radeon_bo_list_fence(&parser->validated, parser->ib->fence); > } > radeon_bo_list_unreserve(&parser->validated); > - for (i = 0; i < parser->nrelocs; i++) { > - if (parser->relocs[i].gobj) { > - mutex_lock(&parser->rdev->ddev->struct_mutex); > - drm_gem_object_unreference(parser->relocs[i].gobj); > - mutex_unlock(&parser->rdev->ddev->struct_mutex); > + if (parser->relocs != NULL) { ^ the only important part, the rest merely covers the new indentation level > + for (i = 0; i < parser->nrelocs; i++) { > + if (parser->relocs[i].gobj) { > + mutex_lock(&parser->rdev->ddev->struct_mutex); > + drm_gem_object_unreference_unlocked(parser->relocs[i].gobj); ^ drm_gem_object_unreference_unlocked() doesn't exist in 2.6.33, yet we can use drm_gem_object_unreference() instead. > + mutex_unlock(&parser->rdev->ddev->struct_mutex); > + } > } > } > kfree(parser->track); As a consequence, I'd suggest to merely backport the NULL pointer check, while ignoring the simplification of using the newly introduced drm_gem_object_unreference_unlocked() from 2.6.34: Signed-off-by: Stefan Lippers-Hollmann Cc: Pauli Nieminen Cc: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c index e9d085021c1f..8c56e95c73cb 100644 --- a/drivers/gpu/drm/radeon/radeon_cs.c +++ b/drivers/gpu/drm/radeon/radeon_cs.c @@ -193,11 +193,13 @@ static void radeon_cs_parser_fini(struct radeon_cs_parser *parser, int error) radeon_bo_list_fence(&parser->validated, parser->ib->fence); } radeon_bo_list_unreserve(&parser->validated); - for (i = 0; i < parser->nrelocs; i++) { - if (parser->relocs[i].gobj) { - mutex_lock(&parser->rdev->ddev->struct_mutex); - drm_gem_object_unreference(parser->relocs[i].gobj); - mutex_unlock(&parser->rdev->ddev->struct_mutex); + if (parser->relocs != NULL) { + for (i = 0; i < parser->nrelocs; i++) { + if (parser->relocs[i].gobj) { + mutex_lock(&parser->rdev->ddev->struct_mutex); + drm_gem_object_unreference(parser->relocs[i].gobj); + mutex_unlock(&parser->rdev->ddev->struct_mutex); + } } } kfree(parser->track);