drm/amdgpu: guard atom_context in devcoredump VBIOS dump

During GPU reset coredump generation, amdgpu_devcoredump_fw_info() unconditionally
dereferences adev->mode_info.atom_context to print VBIOS fields. On reset/teardown
paths this pointer can be NULL, causing a kernel page fault from the deferred
coredump workqueue.

Fix by checking ctx before printing VBIOS fields:

if ctx is valid, print full VBIOS information as before;
This prevents NULL-dereference crashes while preserving coredump output.

Observed page fault log:
[  667.933329] RIP: 0010:amdgpu_devcoredump_format+0x780/0xc00 [amdgpu]
[  667.941517] amdgpu 0002:01:00.0: Dumping IP State
[  667.949660] Code: 8d 57 74 48 c7 c6 01 65 9f c2 48 8d 7d 98 e8 97 96 7a ff 49 8d 97 b4 00 00 00 48 c7 c6 18 65 9f c2 48 8d 7d 98 e8 80 96 7a ff <41> 8b 97 f4 00 00 00 48 c7 c6 2f 65 9f c2 48 8d 7d 98 e8 69 96 7a
[  667.949666] RSP: 0018:ffffc9002302bd50 EFLAGS: 00010246
[  667.949673] RAX: 0000000000000000 RBX: ffff888110600000 RCX: 0000000000000000
[  667.949676] RDX: 000000000000a9b5 RSI: 0000000000000405 RDI: 000000000000a999
[  667.949680] RBP: ffffc9002302be00 R08: ffffffffc09c3084 R09: ffffffffc09c3085
[  667.949684] R10: 0000000000000000 R11: 0000000000000004 R12: 00000000000048e0
[  667.993908] amdgpu 0002:01:00.0: Dumping IP State Completed
[  667.994229] R13: 0000000000000025 R14: 000000000000000c R15: 0000000000000000
[  667.994233] FS:  0000000000000000(0000) GS:ffff88c44c2c9000(0000) knlGS:0000000000000000
[  668.000076] amdgpu 0002:01:00.0: [drm] AMDGPU device coredump file has been created
[  668.008025] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  668.008030] CR2: 00000000000000f4 CR3: 000000011195f001 CR4: 0000000000770ef0
[  668.008035] PKRU: 55555554
[  668.008040] Call Trace:
[  668.008045]  <TASK>
[  668.016010] amdgpu 0002:01:00.0: [drm] Check your /sys/class/drm/card16/device/devcoredump/data
[  668.023967]  ? srso_alias_return_thunk+0x5/0xfbef5
[  668.023988]  ? __pfx___drm_printfn_coredump+0x10/0x10 [drm]
[  668.031950] amdgpu 0003:01:00.0: Dumping IP State
[  668.038159]  ? __pfx___drm_puts_coredump+0x10/0x10 [drm]
[  668.083017] amdgpu 0003:01:00.0: Dumping IP State Completed
[  668.083824]  amdgpu_devcoredump_deferred_work+0x26/0xc0 [amdgpu]
[  668.086163] amdgpu 0003:01:00.0: [drm] AMDGPU device coredump file has been created
[  668.095863]  process_scheduled_works+0xa6/0x420
[  668.095880]  worker_thread+0x12a/0x270
[  668.101223] amdgpu 0003:01:00.0: [drm] Check your /sys/class/drm/card24/device/devcoredump/data
[  668.107441]  kthread+0x10d/0x230
[  668.107451]  ? __pfx_worker_thread+0x10/0x10
[  668.107458]  ? __pfx_kthread+0x10/0x10
[  668.112709] amdgpu 0000:01:00.0: ring vcn_unified_1 timeout, signaled seq=9, emitted seq=10
[  668.118630]  ret_from_fork+0x17c/0x1f0
[  668.118640]  ? __pfx_kthread+0x10/0x10
[  668.118647]  ret_from_fork_asm+0x1a/0x30

Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Suggested-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Jesse Zhang <jesse.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c
index 2b54a67437c26c6abf63d243fe7d30934ddb67d7..28198f3a6e0d0c10aed0acf2ce9fa2873fa9a021 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c
@@ -192,12 +192,16 @@ static void amdgpu_devcoredump_fw_info(struct amdgpu_device *adev,
        drm_printf(p, "VPE feature version: %u, fw version: 0x%08x\n",
                   adev->vpe.feature_version, adev->vpe.fw_version);
 
-       drm_printf(p, "\nVBIOS Information\n");
-       drm_printf(p, "vbios name       : %s\n", ctx->name);
-       drm_printf(p, "vbios pn         : %s\n", ctx->vbios_pn);
-       drm_printf(p, "vbios version    : %d\n", ctx->version);
-       drm_printf(p, "vbios ver_str    : %s\n", ctx->vbios_ver_str);
-       drm_printf(p, "vbios date       : %s\n", ctx->date);
+       if (adev->bios) {
+               drm_printf(p, "\nVBIOS Information\n");
+               drm_printf(p, "vbios name       : %s\n", ctx->name);
+               drm_printf(p, "vbios pn         : %s\n", ctx->vbios_pn);
+               drm_printf(p, "vbios version    : %d\n", ctx->version);
+               drm_printf(p, "vbios ver_str    : %s\n", ctx->vbios_ver_str);
+               drm_printf(p, "vbios date       : %s\n", ctx->date);
+       }else {
+               drm_printf(p, "\nVBIOS Information: NA\n");
+       }
 }
 
 static ssize_t