From 1da80cfa8727abf404fcee44d04743febea54069 Mon Sep 17 00:00:00 2001 From: Ilija Hadzic Date: Wed, 23 Jan 2013 13:59:05 -0500 Subject: [PATCH] drm/radeon: fix a rare case of double kfree If one (but not both) allocations of p->chunks[].kpage[] in radeon_cs_parser_init fail, the error path will free the successfully allocated page, but leave a stale pointer value in the kpage[] field. This will later cause a double-free when radeon_cs_parser_fini is called. This patch fixes the issue by forcing both pointers to NULL after kfree in the error path. The circumstances under which the problem happens are very rare. The card must be AGP and the system must run out of kmalloc area just at the right time so that one allocation succeeds, while the other fails. Signed-off-by: Ilija Hadzic Cc: Herton Ronaldo Krzesinski Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org --- drivers/gpu/drm/radeon/radeon_cs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c index 469661f..5407459 100644 --- a/drivers/gpu/drm/radeon/radeon_cs.c +++ b/drivers/gpu/drm/radeon/radeon_cs.c @@ -286,6 +286,8 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data) p->chunks[p->chunk_ib_idx].kpage[1] == NULL) { kfree(p->chunks[p->chunk_ib_idx].kpage[0]); kfree(p->chunks[p->chunk_ib_idx].kpage[1]); + p->chunks[p->chunk_ib_idx].kpage[0] = NULL; + p->chunks[p->chunk_ib_idx].kpage[1] = NULL; return -ENOMEM; } } -- 2.7.4