[PATCH v2] drm/amd/pm: Vangogh: Fix kernel memory out of bounds write

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>

KASAN reports that the GPU metrics table allocated in
vangogh_tables_init() is not large enough for the memset done in
smu_cmn_init_soft_gpu_metrics(). Condensed report follows:

[   33.861314] BUG: KASAN: slab-out-of-bounds in smu_cmn_init_soft_gpu_metrics+0x73/0x200 [amdgpu]
[   33.861799] Write of size 168 at addr ffff888129f59500 by task mangoapp/1067
...
[   33.861808] CPU: 6 UID: 1000 PID: 1067 Comm: mangoapp Tainted: G        W          6.12.0-rc4 #356 1a56f59a8b5182eeaf67eb7cb8b13594dd23b544
[   33.861816] Tainted: [W]=WARN
[   33.861818] Hardware name: Valve Galileo/Galileo, BIOS F7G0107 12/01/2023
[   33.861822] Call Trace:
[   33.861826]  <TASK>
[   33.861829]  dump_stack_lvl+0x66/0x90
[   33.861838]  print_report+0xce/0x620
[   33.861853]  kasan_report+0xda/0x110
[   33.862794]  kasan_check_range+0xfd/0x1a0
[   33.862799]  __asan_memset+0x23/0x40
[   33.862803]  smu_cmn_init_soft_gpu_metrics+0x73/0x200 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779]
[   33.863306]  vangogh_get_gpu_metrics_v2_4+0x123/0xad0 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779]
[   33.864257]  vangogh_common_get_gpu_metrics+0xb0c/0xbc0 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779]
[   33.865682]  amdgpu_dpm_get_gpu_metrics+0xcc/0x110 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779]
[   33.866160]  amdgpu_get_gpu_metrics+0x154/0x2d0 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779]
[   33.867135]  dev_attr_show+0x43/0xc0
[   33.867147]  sysfs_kf_seq_show+0x1f1/0x3b0
[   33.867155]  seq_read_iter+0x3f8/0x1140
[   33.867173]  vfs_read+0x76c/0xc50
[   33.867198]  ksys_read+0xfb/0x1d0
[   33.867214]  do_syscall_64+0x90/0x160
...
[   33.867353] Allocated by task 378 on cpu 7 at 22.794876s:
[   33.867358]  kasan_save_stack+0x33/0x50
[   33.867364]  kasan_save_track+0x17/0x60
[   33.867367]  __kasan_kmalloc+0x87/0x90
[   33.867371]  vangogh_init_smc_tables+0x3f9/0x840 [amdgpu]
[   33.867835]  smu_sw_init+0xa32/0x1850 [amdgpu]
[   33.868299]  amdgpu_device_init+0x467b/0x8d90 [amdgpu]
[   33.868733]  amdgpu_driver_load_kms+0x19/0xf0 [amdgpu]
[   33.869167]  amdgpu_pci_probe+0x2d6/0xcd0 [amdgpu]
[   33.869608]  local_pci_probe+0xda/0x180
[   33.869614]  pci_device_probe+0x43f/0x6b0

Empirically we can confirm that the former allocates 152 bytes for the
table, while the latter memsets the 168 large block.

Root cause appears that when GPU metrics tables for v2_4 parts were added
it was not considered to enlarge the table to fit.

The fix in this patch is rather "brute force" and perhaps later should be
done in a smarter way, by extracting and consolidating the part version to
size logic to a common helper, instead of brute forcing the largest
possible allocation. Nevertheless, for now this works and fixes the out of
bounds write.

v2:
 * Drop impossible v3_0 case. (Mario)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
Fixes: 41cec40bc9ba ("drm/amd/pm: Vangogh: Add new gpu_metrics_v2_4 to acquire gpu_metrics")
Cc: Mario Limonciello <mario.limonciello at amd.com>
Cc: Evan Quan <evan.quan at amd.com>
Cc: Wenyou Yang <WenYou.Yang at amd.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: <stable at vger.kernel.org> # v6.6+
---
 drivers/gpu/drm/amd/pm/swsmu/smu11/vangogh_ppt.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/vangogh_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu11/vangogh_ppt.c
index 22737b11b1bf..1fe020f1f4db 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/smu11/vangogh_ppt.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/vangogh_ppt.c
@@ -242,7 +242,9 @@ static int vangogh_tables_init(struct smu_context *smu)
 		goto err0_out;
 	smu_table->metrics_time = 0;
 
-	smu_table->gpu_metrics_table_size = max(sizeof(struct gpu_metrics_v2_3), sizeof(struct gpu_metrics_v2_2));
+	smu_table->gpu_metrics_table_size = sizeof(struct gpu_metrics_v2_2);
+	smu_table->gpu_metrics_table_size = max(smu_table->gpu_metrics_table_size, sizeof(struct gpu_metrics_v2_3));
+	smu_table->gpu_metrics_table_size = max(smu_table->gpu_metrics_table_size, sizeof(struct gpu_metrics_v2_4));
 	smu_table->gpu_metrics_table = kzalloc(smu_table->gpu_metrics_table_size, GFP_KERNEL);
 	if (!smu_table->gpu_metrics_table)
 		goto err1_out;
-- 
2.46.0