> But immediately you call "sched_job = amd_sched_entity_peek_job(entity)", keep in mind that this point the "entity" may > Already be a wild pointer, since above "sched_select_entity' unlock the RQ's spinlock No, that is unproblematic. The entity won't be freed until all its jobs are freed. > For gpu reset feature, it's more complicated, because in run_job() routine we need check entity's guilty pointer, but that time > The entity from sched_job->s_entity may also already a wild pointer Crap, that is indeed a problem. We should probably rather move that check into amd_sched_entity_pop_job(). Problem is that we can't check the entity then again during job recovery. Need to take a second look at this. Christian. Am 24.10.2017 um 12:17 schrieb Liu, Monk: > You get entity from "amd_sched_select_entity", and after that the spinlock of RQ backing this entity is also unlocked, > > But immediately you call "sched_job = amd_sched_entity_peek_job(entity)", keep in mind that this point the "entity" may > Already be a wild pointer, since above "sched_select_entity' unlock the RQ's spinlock > > For gpu reset feature, it's more complicated, because in run_job() routine we need check entity's guilty pointer, but that time > The entity from sched_job->s_entity may also already a wild pointer > > > Hah, headache > > BR Monk > > -----Original Message----- > From: Koenig, Christian > Sent: 2017å¹´10æ??24æ?¥ 18:13 > To: Liu, Monk <Monk.Liu at amd.com>; Zhou, David(ChunMing) <David1.Zhou at amd.com>; amd-gfx at lists.freedesktop.org > Subject: Re: [PATCH] drm/amd/scheduler: fix one used-after-free case for job->s_entity > > I thought we had fixed that one as well. > > The entity isn't accessed any more after amd_sched_entity_pop_job(). > > Regards, > Christian. > > Am 24.10.2017 um 12:06 schrieb Liu, Monk: >> Christian >> >> Actually there are more wild pointer issue for entity in scheduler's main routine .... >> >> >> See the message I replied to David >> >> BR Monk >> >> -----Original Message----- >> From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf >> Of Christian K?nig >> Sent: 2017å¹´10æ??24æ?¥ 18:01 >> To: Zhou, David(ChunMing) <David1.Zhou at amd.com>; >> amd-gfx at lists.freedesktop.org >> Subject: Re: [PATCH] drm/amd/scheduler: fix one used-after-free case >> for job->s_entity >> >> Andrey already submitted a fix for this a few days ago. >> >> Christian. >> >> Am 24.10.2017 um 11:55 schrieb Chunming Zhou: >>> The s_entity presented process could already be closed when calling amdgpu_job_free_cb. >>> the s_entity will be buggy pointer after it's freed. See below calltrace: >>> >>> [ 355.616964] >>> ================================================================== >>> [ 355.617191] BUG: KASAN: use-after-free in >>> amdgpu_job_free_cb+0x2f/0xc0 [amdgpu] [ 355.617197] Read of size 8 >>> at addr ffff88039d593c40 by task kworker/9:1/100 >>> >>> [ 355.617206] CPU: 9 PID: 100 Comm: kworker/9:1 Not tainted >>> 4.13.0-custom #1 [ 355.617208] Hardware name: Gigabyte Technology >>> Co., Ltd. Default string/X99P-SLI-CF, BIOS F23 07/22/2016 [ >>> 355.617342] Workqueue: events amd_sched_job_finish [amdgpu] [ 355.617344] Call Trace: >>> [ 355.617351] dump_stack+0x63/0x8d >>> [ 355.617356] print_address_description+0x70/0x290 >>> [ 355.617474] ? amdgpu_job_free_cb+0x2f/0xc0 [amdgpu] [ >>> 355.617477] >>> kasan_report+0x265/0x350 [ 355.617479] __asan_load8+0x54/0x90 [ >>> 355.617603] amdgpu_job_free_cb+0x2f/0xc0 [amdgpu] [ 355.617721] >>> amd_sched_job_finish+0x161/0x180 [amdgpu] [ 355.617725] >>> process_one_work+0x2ab/0x700 [ 355.617727] worker_thread+0x90/0x720 >>> [ 355.617731] kthread+0x18c/0x1e0 [ 355.617732] ? >>> process_one_work+0x700/0x700 [ 355.617735] ? >>> kthread_create_on_node+0xb0/0xb0 [ 355.617738] >>> ret_from_fork+0x25/0x30 >>> >>> [ 355.617742] Allocated by task 1347: >>> [ 355.617747] save_stack_trace+0x1b/0x20 [ 355.617749] >>> save_stack+0x46/0xd0 [ 355.617751] kasan_kmalloc+0xad/0xe0 [ >>> 355.617753] kmem_cache_alloc_trace+0xef/0x200 [ 355.617853] >>> amdgpu_driver_open_kms+0x98/0x290 [amdgpu] [ 355.617883] >>> drm_open+0x38c/0x6e0 [drm] [ 355.617908] drm_stub_open+0x144/0x1b0 >>> [drm] [ 355.617911] chrdev_open+0x180/0x320 [ 355.617913] >>> do_dentry_open+0x3a2/0x570 [ 355.617915] vfs_open+0x86/0xe0 [ >>> 355.617918] path_openat+0x49e/0x1db0 [ 355.617919] >>> do_filp_open+0x11c/0x1a0 [ 355.617921] do_sys_open+0x16f/0x2a0 [ >>> 355.617923] SyS_open+0x1e/0x20 [ 355.617926] >>> do_syscall_64+0xea/0x210 [ 355.617928] >>> return_from_SYSCALL_64+0x0/0x6a >>> >>> [ 355.617931] Freed by task 1347: >>> [ 355.617934] save_stack_trace+0x1b/0x20 [ 355.617936] >>> save_stack+0x46/0xd0 [ 355.617937] kasan_slab_free+0x70/0xc0 [ >>> 355.617939] kfree+0x9d/0x1c0 [ 355.618038] >>> amdgpu_driver_postclose_kms+0x1bc/0x3e0 [amdgpu] [ 355.618063] >>> drm_release+0x454/0x610 [drm] [ 355.618065] __fput+0x177/0x350 [ >>> 355.618066] ____fput+0xe/0x10 [ 355.618068] >>> task_work_run+0xa0/0xc0 [ 355.618070] do_exit+0x456/0x1320 [ >>> 355.618072] >>> do_group_exit+0x86/0x130 [ 355.618074] SyS_exit_group+0x1d/0x20 [ >>> 355.618076] do_syscall_64+0xea/0x210 [ 355.618078] >>> return_from_SYSCALL_64+0x0/0x6a >>> >>> [ 355.618081] The buggy address belongs to the object at ffff88039d593b80 >>> which belongs to the cache kmalloc-2048 of size >>> 2048 [ 355.618085] The buggy address is located 192 bytes inside of >>> 2048-byte region [ffff88039d593b80, >>> ffff88039d594380) [ 355.618087] The buggy address belongs to the page: >>> [ 355.618091] page:ffffea000e756400 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 >>> [ 355.618095] flags: 0x2ffff0000008100(slab|head) [ 355.618099] raw: >>> 02ffff0000008100 0000000000000000 0000000000000000 00000001000f000f [ >>> 355.618103] raw: ffffea000edb0600 0000000200000002 ffff8803bfc0ea00 >>> 0000000000000000 [ 355.618105] page dumped because: kasan: bad >>> access detected >>> >>> [ 355.618108] Memory state around the buggy address: >>> [ 355.618110] ffff88039d593b00: fc fc fc fc fc fc fc fc fc fc fc fc >>> fc fc fc fc [ 355.618113] ffff88039d593b80: fb fb fb fb fb fb fb fb >>> fb fb fb fb fb fb fb fb [ 355.618116] >ffff88039d593c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>> [ 355.618117] ^ >>> [ 355.618120] ffff88039d593c80: fb fb fb fb fb fb fb fb fb fb fb fb >>> fb fb fb fb [ 355.618122] ffff88039d593d00: fb fb fb fb fb fb fb fb >>> fb fb fb fb fb fb fb fb [ 355.618124] >>> ================================================================== >>> [ 355.618126] Disabling lock debugging due to kernel taint >>> >>> Change-Id: I8ff7122796b8cd16fc26e9c40e8d4c8153d67e0c >>> Signed-off-by: Chunming Zhou <david1.zhou at amd.com> >>> --- >>> drivers/gpu/drm/amd/scheduler/gpu_scheduler.c | 1 + >>> drivers/gpu/drm/amd/scheduler/gpu_scheduler.h | 27 ++++++++++++++------------- >>> 2 files changed, 15 insertions(+), 13 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c >>> b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c >>> index 007fdbd..8101ed7 100644 >>> --- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c >>> +++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c >>> @@ -535,6 +535,7 @@ int amd_sched_job_init(struct amd_sched_job *job, >>> if (!job->s_fence) >>> return -ENOMEM; >>> job->id = atomic64_inc_return(&sched->job_id_count); >>> + job->priority = job->s_entity->rq - job->sched->sched_rq; >>> >>> INIT_WORK(&job->finish_work, amd_sched_job_finish); >>> INIT_LIST_HEAD(&job->node); >>> diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h >>> b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h >>> index e21299c..8808eb1 100644 >>> --- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h >>> +++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h >>> @@ -77,6 +77,18 @@ struct amd_sched_fence { >>> void *owner; >>> }; >>> >>> +enum amd_sched_priority { >>> + AMD_SCHED_PRIORITY_MIN, >>> + AMD_SCHED_PRIORITY_LOW = AMD_SCHED_PRIORITY_MIN, >>> + AMD_SCHED_PRIORITY_NORMAL, >>> + AMD_SCHED_PRIORITY_HIGH_SW, >>> + AMD_SCHED_PRIORITY_HIGH_HW, >>> + AMD_SCHED_PRIORITY_KERNEL, >>> + AMD_SCHED_PRIORITY_MAX, >>> + AMD_SCHED_PRIORITY_INVALID = -1, >>> + AMD_SCHED_PRIORITY_UNSET = -2 >>> +}; >>> + >>> struct amd_sched_job { >>> struct amd_gpu_scheduler *sched; >>> struct amd_sched_entity *s_entity; >>> @@ -87,6 +99,7 @@ struct amd_sched_job { >>> struct delayed_work work_tdr; >>> uint64_t id; >>> atomic_t karma; >>> + enum amd_sched_priority priority; >>> }; >>> >>> extern const struct dma_fence_ops amd_sched_fence_ops_scheduled; >>> @@ >>> -118,18 +131,6 @@ struct amd_sched_backend_ops { >>> void (*free_job)(struct amd_sched_job *sched_job); >>> }; >>> >>> -enum amd_sched_priority { >>> - AMD_SCHED_PRIORITY_MIN, >>> - AMD_SCHED_PRIORITY_LOW = AMD_SCHED_PRIORITY_MIN, >>> - AMD_SCHED_PRIORITY_NORMAL, >>> - AMD_SCHED_PRIORITY_HIGH_SW, >>> - AMD_SCHED_PRIORITY_HIGH_HW, >>> - AMD_SCHED_PRIORITY_KERNEL, >>> - AMD_SCHED_PRIORITY_MAX, >>> - AMD_SCHED_PRIORITY_INVALID = -1, >>> - AMD_SCHED_PRIORITY_UNSET = -2 >>> -}; >>> - >>> /** >>> * One scheduler is implemented for each hardware ring >>> */ >>> @@ -183,7 +184,7 @@ void amd_sched_job_kickout(struct amd_sched_job *s_job); >>> static inline enum amd_sched_priority >>> amd_sched_get_job_priority(struct amd_sched_job *job) >>> { >>> - return (job->s_entity->rq - job->sched->sched_rq); >>> + return job->priority; >>> } >>> >>> #endif >> _______________________________________________ >> amd-gfx mailing list >> amd-gfx at lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/amd-gfx >
