Am 13.03.24 um 22:20 schrieb vitaly.prosyak@xxxxxxx:
From: Vitaly Prosyak <vitaly.prosyak@xxxxxxx>
The bug can be triggered by sending an amdgpu_cs_wait_ioctl
to the AMDGPU DRM driver on any ASICs with valid context.
The bug was reported by Joonkyo Jung <joonkyoj@xxxxxxxxxxxx>.
For example the following code:
static void Syzkaller2(int fd)
{
union drm_amdgpu_ctx arg1;
union drm_amdgpu_wait_cs arg2;
arg1.in.op = AMDGPU_CTX_OP_ALLOC_CTX;
ret = drmIoctl(fd, 0x140106442 /* amdgpu_ctx_ioctl */, &arg1);
arg2.in.handle = 0x0;
arg2.in.timeout = 0x2000000000000;
arg2.in.ip_type = AMD_IP_VPE /* 0x9 */;
arg2->in.ip_instance = 0x0;
arg2.in.ring = 0x0;
arg2.in.ctx_id = arg1.out.alloc.ctx_id;
drmIoctl(fd, 0xc0206449 /* AMDGPU_WAIT_CS * /, &arg2);
}
The ioctl AMDGPU_WAIT_CS without previously submitted job could be assumed that
the error should be returned, but the following commit 1decbf6bb0b4dc56c9da6c5e57b994ebfc2be3aa
modified the logic and allowed to have sched_rq equal to NULL.
As a result when there is no job the ioctl AMDGPU_WAIT_CS returns success.
The change fixes null-ptr-deref in init entity and the stack below demonstrates
the error condition:
[ +0.000007] BUG: kernel NULL pointer dereference, address: 0000000000000028
[ +0.007086] #PF: supervisor read access in kernel mode
[ +0.005234] #PF: error_code(0x0000) - not-present page
[ +0.005232] PGD 0 P4D 0
[ +0.002501] Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
[ +0.005034] CPU: 10 PID: 9229 Comm: amd_basic Tainted: G B W L 6.7.0+ #4
[ +0.007797] Hardware name: ASUS System Product Name/ROG STRIX B550-F GAMING (WI-FI), BIOS 1401 12/03/2020
[ +0.009798] RIP: 0010:drm_sched_entity_init+0x2d3/0x420 [gpu_sched]
[ +0.006426] Code: 80 00 00 00 00 00 00 00 e8 1a 81 82 e0 49 89 9c 24 c0 00 00 00 4c 89 ef e8 4a 80 82 e0 49 8b 5d 00 48 8d 7b 28 e8 3d 80 82 e0 <48> 83 7b 28 00 0f 84 28 01 00 00 4d 8d ac 24 98 00 00 00 49 8d 5c
[ +0.019094] RSP: 0018:ffffc90014c1fa40 EFLAGS: 00010282
[ +0.005237] RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8113f3fa
[ +0.007326] RDX: fffffbfff0a7889d RSI: 0000000000000008 RDI: ffffffff853c44e0
[ +0.007264] RBP: ffffc90014c1fa80 R08: 0000000000000001 R09: fffffbfff0a7889c
[ +0.007266] R10: ffffffff853c44e7 R11: 0000000000000001 R12: ffff8881a719b010
[ +0.007263] R13: ffff88810d412748 R14: 0000000000000002 R15: 0000000000000000
[ +0.007264] FS: 00007ffff7045540(0000) GS:ffff8883cc900000(0000) knlGS:0000000000000000
[ +0.008236] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ +0.005851] CR2: 0000000000000028 CR3: 000000011912e000 CR4: 0000000000350ef0
[ +0.007175] Call Trace:
[ +0.002561] <TASK>
[ +0.002141] ? show_regs+0x6a/0x80
[ +0.003473] ? __die+0x25/0x70
[ +0.003124] ? page_fault_oops+0x214/0x720
[ +0.004179] ? preempt_count_sub+0x18/0xc0
[ +0.004093] ? __pfx_page_fault_oops+0x10/0x10
[ +0.004590] ? srso_return_thunk+0x5/0x5f
[ +0.004000] ? vprintk_default+0x1d/0x30
[ +0.004063] ? srso_return_thunk+0x5/0x5f
[ +0.004087] ? vprintk+0x5c/0x90
[ +0.003296] ? drm_sched_entity_init+0x2d3/0x420 [gpu_sched]
[ +0.005807] ? srso_return_thunk+0x5/0x5f
[ +0.004090] ? _printk+0xb3/0xe0
[ +0.003293] ? __pfx__printk+0x10/0x10
[ +0.003735] ? asm_sysvec_apic_timer_interrupt+0x1b/0x20
[ +0.005482] ? do_user_addr_fault+0x345/0x770
[ +0.004361] ? exc_page_fault+0x64/0xf0
[ +0.003972] ? asm_exc_page_fault+0x27/0x30
[ +0.004271] ? add_taint+0x2a/0xa0
[ +0.003476] ? drm_sched_entity_init+0x2d3/0x420 [gpu_sched]
[ +0.005812] amdgpu_ctx_get_entity+0x3f9/0x770 [amdgpu]
[ +0.009530] ? finish_task_switch.isra.0+0x129/0x470
[ +0.005068] ? __pfx_amdgpu_ctx_get_entity+0x10/0x10 [amdgpu]
[ +0.010063] ? __kasan_check_write+0x14/0x20
[ +0.004356] ? srso_return_thunk+0x5/0x5f
[ +0.004001] ? mutex_unlock+0x81/0xd0
[ +0.003802] ? srso_return_thunk+0x5/0x5f
[ +0.004096] amdgpu_cs_wait_ioctl+0xf6/0x270 [amdgpu]
[ +0.009355] ? __pfx_amdgpu_cs_wait_ioctl+0x10/0x10 [amdgpu]
[ +0.009981] ? srso_return_thunk+0x5/0x5f
[ +0.004089] ? srso_return_thunk+0x5/0x5f
[ +0.004090] ? __srcu_read_lock+0x20/0x50
[ +0.004096] drm_ioctl_kernel+0x140/0x1f0 [drm]
[ +0.005080] ? __pfx_amdgpu_cs_wait_ioctl+0x10/0x10 [amdgpu]
[ +0.009974] ? __pfx_drm_ioctl_kernel+0x10/0x10 [drm]
[ +0.005618] ? srso_return_thunk+0x5/0x5f
[ +0.004088] ? __kasan_check_write+0x14/0x20
[ +0.004357] drm_ioctl+0x3da/0x730 [drm]
[ +0.004461] ? __pfx_amdgpu_cs_wait_ioctl+0x10/0x10 [amdgpu]
[ +0.009979] ? __pfx_drm_ioctl+0x10/0x10 [drm]
[ +0.004993] ? srso_return_thunk+0x5/0x5f
[ +0.004090] ? __kasan_check_write+0x14/0x20
[ +0.004356] ? srso_return_thunk+0x5/0x5f
[ +0.004090] ? _raw_spin_lock_irqsave+0x99/0x100
[ +0.004712] ? __pfx__raw_spin_lock_irqsave+0x10/0x10
[ +0.005063] ? __pfx_arch_do_signal_or_restart+0x10/0x10
[ +0.005477] ? srso_return_thunk+0x5/0x5f
[ +0.004000] ? preempt_count_sub+0x18/0xc0
[ +0.004237] ? srso_return_thunk+0x5/0x5f
[ +0.004090] ? _raw_spin_unlock_irqrestore+0x27/0x50
[ +0.005069] amdgpu_drm_ioctl+0x7e/0xe0 [amdgpu]
[ +0.008912] __x64_sys_ioctl+0xcd/0x110
[ +0.003918] do_syscall_64+0x5f/0xe0
[ +0.003649] ? noist_exc_debug+0xe6/0x120
[ +0.004095] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ +0.005150] RIP: 0033:0x7ffff7b1a94f
[ +0.003647] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <41> 89 c0 3d 00 f0 ff ff 77 1f 48 8b 44 24 18 64 48 2b 04 25 28 00
[ +0.019097] RSP: 002b:00007fffffffe0a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ +0.007708] RAX: ffffffffffffffda RBX: 000055555558b360 RCX: 00007ffff7b1a94f
[ +0.007176] RDX: 000055555558b360 RSI: 00000000c0206449 RDI: 0000000000000003
[ +0.007326] RBP: 00000000c0206449 R08: 000055555556ded0 R09: 000000007fffffff
[ +0.007176] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffffffe5d8
[ +0.007238] R13: 0000000000000003 R14: 000055555555cba8 R15: 00007ffff7ffd040
[ +0.007250] </TASK>
Cc: Christian Koenig <christian.koenig@xxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: Luben Tuikov <ltuikov89@xxxxxxxxx>
Cc: Bas Nieuwenhuizen <bas@xxxxxxxxxxxxxxxxxxx>
Cc: Joonkyo Jung <joonkyoj@xxxxxxxxxxxx>
Cc: Dokyung Song <dokyungs@xxxxxxxxxxxx>
Cc: <jisoo.jang@xxxxxxxxxxxx>
Cc: <yw9865@xxxxxxxxxxxx>
Signed-off-by: Vitaly Prosyak <vitaly.prosyak@xxxxxxx>
---
drivers/gpu/drm/scheduler/sched_entity.c | 34 +++++++++++++-----------
1 file changed, 18 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 3c4f5a392b06..b5f79feb300a 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -75,23 +75,25 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
RCU_INIT_POINTER(entity->last_scheduled, NULL);
RB_CLEAR_NODE(&entity->rb_tree_node);
- if (!sched_list[0]->sched_rq) {
- /* Warn drivers not to do this and to fix their DRM
- * calling order.
- */
- pr_warn("%s: called with uninitialized scheduler\n", __func__);
- } else if (num_sched_list) {
- /* The "priority" of an entity cannot exceed the number of run-queues of a
- * scheduler. Protect against num_rqs being 0, by converting to signed. Choose
- * the lowest priority available.
- */
- if (entity->priority >= sched_list[0]->num_rqs) {
- drm_err(sched_list[0], "entity with out-of-bounds priority:%u num_rqs:%u\n",
- entity->priority, sched_list[0]->num_rqs);
- entity->priority = max_t(s32, (s32) sched_list[0]->num_rqs - 1,
- (s32) DRM_SCHED_PRIORITY_KERNEL);
+ if (sched_list[0]) {
That check is actually illegal since every entry covered by num_sched
should be non-NULL.
+ if (!sched_list[0]->sched_rq) {
That check here is broken. This needs to be num_sched_list &&
!sched_list[0]->sched_rq.
It's perfectly valid to initialize an entity without having a valid
scheduler attached. It's just not valid to use the scheduler before it
is initialized itself.
Regards,
Christian.
+ /* Warn drivers not to do this and to fix their DRM
+ * calling order.
+ */
+ pr_warn("%s: called with uninitialized scheduler\n", __func__);
+ } else if (num_sched_list) {
+ /* The "priority" of an entity cannot exceed the number of run-queues of a
+ * scheduler. Protect against num_rqs being 0, by converting to signed. Choose
+ * the lowest priority available.
+ */
+ if (entity->priority >= sched_list[0]->num_rqs) {
+ drm_err(sched_list[0], "entity with out-of-bounds priority:%u num_rqs:%u\n",
+ entity->priority, sched_list[0]->num_rqs);
+ entity->priority = max_t(s32, (s32) sched_list[0]->num_rqs - 1,
+ (s32) DRM_SCHED_PRIORITY_KERNEL);
+ }
+ entity->rq = sched_list[0]->sched_rq[entity->priority];
}
- entity->rq = sched_list[0]->sched_rq[entity->priority];
}
init_completion(&entity->entity_idle);
