[PATCH 3.2 082/221] drm/radeon: fix DRM_IOCTL_RADEON_CS oops

Ben Hutchings
2015-05-05T01:41:59Z

From: Tommi Rantala <tt.rantala@gmail.com>

commit a28b2a47edcd0cb7c051b445f71a426000394606 upstream.

Passing zeroed drm_radeon_cs struct to DRM_IOCTL_RADEON_CS produces the
following oops.

Fix by always calling INIT_LIST_HEAD() to avoid the crash in list_sort().

----------------------------------

#include <stdint.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <drm/radeon_drm.h>

static const struct drm_radeon_cs cs;

int main(int argc, char **argv)
{
return ioctl(open(argv[1], O_RDWR), DRM_IOCTL_RADEON_CS, &cs);
}

----------------------------------

[ttrantal@test2 ~]$ ./main /dev/dri/card0
[ 46.904650] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 46.905022] IP: [<ffffffff814d6df2>] list_sort+0x42/0x240
[ 46.905022] PGD 68f29067 PUD 688b5067 PMD 0
[ 46.905022] Oops: 0002 [#1] SMP
[ 46.905022] CPU: 0 PID: 2413 Comm: main Not tainted 4.0.0-rc1+ #58
[ 46.905022] Hardware name: Hewlett-Packard HP Compaq dc5750 Small Form Factor/0A64h, BIOS 786E3 v02.10 01/25/2007
[ 46.905022] task: ffff880058e2bcc0 ti: ffff880058e64000 task.ti: ffff880058e64000
[ 46.905022] RIP: 0010:[<ffffffff814d6df2>] [<ffffffff814d6df2>] list_sort+0x42/0x240
[ 46.905022] RSP: 0018:ffff880058e67998 EFLAGS: 00010246
[ 46.905022] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 46.905022] RDX: ffffffff81644410 RSI: ffff880058e67b40 RDI: ffff880058e67a58
[ 46.905022] RBP: ffff880058e67a88 R08: 0000000000000000 R09: 0000000000000000
[ 46.905022] R10: ffff880058e2bcc0 R11: ffffffff828e6ca0 R12: ffffffff81644410
[ 46.905022] R13: ffff8800694b8018 R14: 0000000000000000 R15: ffff880058e679b0
[ 46.905022] FS: 00007fdc65a65700(0000) GS:ffff88006d600000(0000) knlGS:0000000000000000
[ 46.905022] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 46.905022] CR2: 0000000000000000 CR3: 0000000058dd9000 CR4: 00000000000006f0
[ 46.905022] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 46.905022] DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
[ 46.905022] Stack:
[ 46.905022] ffff880058e67b40 ffff880058e2bcc0 ffff880058e67a78 0000000000000000
[ 46.905022] 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 46.905022] 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 46.905022] Call Trace:
[ 46.905022] [<ffffffff81644a65>] radeon_cs_parser_fini+0x195/0x220
[ 46.905022] [<ffffffff81645069>] radeon_cs_ioctl+0xa9/0x960
[ 46.905022] [<ffffffff815e1f7c>] drm_ioctl+0x19c/0x640
[ 46.905022] [<ffffffff810f8fdd>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[ 46.905022] [<ffffffff810f90ad>] ? trace_hardirqs_on+0xd/0x10
[ 46.905022] [<ffffffff8160c066>] radeon_drm_ioctl+0x46/0x80
[ 46.905022] [<ffffffff81211868>] do_vfs_ioctl+0x318/0x570
[ 46.905022] [<ffffffff81462ef6>] ? selinux_file_ioctl+0x56/0x110
[ 46.905022] [<ffffffff81211b41>] SyS_ioctl+0x81/0xa0
[ 46.905022] [<ffffffff81dc6312>] system_call_fastpath+0x12/0x17
[ 46.905022] Code: 48 89 b5 10 ff ff ff 0f 84 03 01 00 00 4c 8d bd 28 ff ff
ff 31 c0 48 89 fb b9 15 00 00 00 49 89 d4 4c 89 ff f3 48 ab 48 8b 46 08 <48> c7
00 00 00 00 00 48 8b 0e 48 85 c9 0f 84 7d 00 00 00 c7 85
[ 46.905022] RIP [<ffffffff814d6df2>] list_sort+0x42/0x240
[ 46.905022] RSP <ffff880058e67998>
[ 46.905022] CR2: 0000000000000000
[ 47.149253] ---[ end trace 09576b4e8b2c20b8 ]---

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Tommi Rantala <tt.rantala@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/gpu/drm/radeon/radeon_cs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -95,11 +95,13 @@ int radeon_cs_parser_init(struct radeon_
uint64_t *chunk_array_ptr;
unsigned size, i, flags = 0;

+ INIT_LIST_HEAD(&p->validated);
+
if (!cs->num_chunks) {
return 0;
}
+
/* get chunks */
- INIT_LIST_HEAD(&p->validated);
p->idx = 0;
p->chunk_ib_idx = -1;
p->chunk_relocs_idx = -1;