[PATCH 6.18 115/752] drm/amdgpu/ras: Move ras data alloc before bad page check

Sasha Levin
2026-02-28T17:49:45Z

From: Asad Kamal <asad.kamal@amd.com>

[ Upstream commit bd68a1404b6fa2e7e9957b38ba22616faba43e75 ]

In the rare event if eeprom has only invalid address entries,
allocation is skipped, this causes following NULL pointer issue
[ 547.103445] BUG: kernel NULL pointer dereference, address: 0000000000000010
[ 547.118897] #PF: supervisor read access in kernel mode
[ 547.130292] #PF: error_code(0x0000) - not-present page
[ 547.141689] PGD 124757067 P4D 0
[ 547.148842] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 547.158504] CPU: 49 PID: 8167 Comm: cat Tainted: G OE 6.8.0-38-generic #38-Ubuntu
[ 547.177998] Hardware name: Supermicro AS -8126GS-TNMR/H14DSG-OD, BIOS 1.7 09/12/2025
[ 547.195178] RIP: 0010:amdgpu_ras_sysfs_badpages_read+0x2f2/0x5d0 [amdgpu]
[ 547.210375] Code: e8 63 78 82 c0 45 31 d2 45 3b 75 08 48 8b 45 a0 73 44 44 89 f1 48 8b 7d 88 48 89 ca 48 c1 e2 05 48 29 ca 49 8b 4d 00 48 01 d1 <48> 83 79 10 00 74 17 49 63 f2 48 8b 49 08 41 83 c2 01 48 8d 34 76
[ 547.252045] RSP: 0018:ffa0000067287ac0 EFLAGS: 00010246
[ 547.263636] RAX: ff11000167c28130 RBX: ff11000127600000 RCX: 0000000000000000
[ 547.279467] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ff11000125b1c800
[ 547.295298] RBP: ffa0000067287b50 R08: 0000000000000000 R09: 0000000000000000
[ 547.311129] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 547.326959] R13: ff11000217b1de00 R14: 0000000000000000 R15: 0000000000000092
[ 547.342790] FS: 0000746e59d14740(0000) GS:ff11017dfda80000(0000) knlGS:0000000000000000
[ 547.360744] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 547.373489] CR2: 0000000000000010 CR3: 000000019585e001 CR4: 0000000000f71ef0
[ 547.389321] PKRU: 55555554
[ 547.395316] Call Trace:
[ 547.400737] <TASK>
[ 547.405386] ? show_regs+0x6d/0x80
[ 547.412929] ? __die+0x24/0x80
[ 547.419697] ? page_fault_oops+0x99/0x1b0
[ 547.428588] ? do_user_addr_fault+0x2ee/0x6b0
[ 547.438249] ? exc_page_fault+0x83/0x1b0
[ 547.446949] ? asm_exc_page_fault+0x27/0x30
[ 547.456225] ? amdgpu_ras_sysfs_badpages_read+0x2f2/0x5d0 [amdgpu]
[ 547.470040] ? mas_wr_modify+0xcd/0x140
[ 547.478548] sysfs_kf_bin_read+0x63/0xb0
[ 547.487248] kernfs_file_read_iter+0xa1/0x190
[ 547.496909] kernfs_fop_read_iter+0x25/0x40
[ 547.506182] vfs_read+0x255/0x390

This also result in space left assigned to negative values.
Moving data alloc call before bad page check resolves both the issue.

Signed-off-by: Asad Kamal <asad.kamal@amd.com>
Suggested-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
index ca5f99df1ac20..e9ed1a3b135cc 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
@@ -2892,6 +2892,11 @@ static int __amdgpu_ras_restore_bad_pages(struct amdgpu_device *adev,
struct ras_err_handler_data *data = con->eh_data;

for (j = 0; j < count; j++) {
+ if (!data->space_left &&
+ amdgpu_ras_realloc_eh_data_space(adev, data, 256)) {
+ return -ENOMEM;
+ }
+
if (amdgpu_ras_check_bad_page_unlock(con,
bps[j].retired_page << AMDGPU_GPU_PAGE_SHIFT)) {
data->count++;
@@ -2899,11 +2904,6 @@ static int __amdgpu_ras_restore_bad_pages(struct amdgpu_device *adev,
continue;
}

- if (!data->space_left &&
- amdgpu_ras_realloc_eh_data_space(adev, data, 256)) {
- return -ENOMEM;
- }
-
amdgpu_ras_reserve_page(adev, bps[j].retired_page);

memcpy(&data->bps[data->count], &(bps[j]),
--
2.51.0