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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Yintian Tao" <yttao@amd.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"Sasha Levin" <sashal@kernel.org>,
	dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org,
	linaro-mm-sig@lists.linaro.org
Subject: [PATCH AUTOSEL 5.5 31/35] drm/scheduler: fix rare NULL ptr race
Date: Mon,  6 Apr 2020 20:00:53 -0400	[thread overview]
Message-ID: <20200407000058.16423-31-sashal@kernel.org> (raw)
In-Reply-To: <20200407000058.16423-1-sashal@kernel.org>

From: Yintian Tao <yttao@amd.com>

[ Upstream commit 3c0fdf3302cb4f186c871684eac5c407a107e480 ]

There is one one corner case at dma_fence_signal_locked
which will raise the NULL pointer problem just like below.
->dma_fence_signal
    ->dma_fence_signal_locked
	->test_and_set_bit
here trigger dma_fence_release happen due to the zero of fence refcount.

->dma_fence_put
    ->dma_fence_release
	->drm_sched_fence_release_scheduled
	    ->call_rcu
here make the union fled “cb_list” at finished fence
to NULL because struct rcu_head contains two pointer
which is same as struct list_head cb_list

Therefore, to hold the reference of finished fence at drm_sched_process_job
to prevent the null pointer during finished fence dma_fence_signal

[  732.912867] BUG: kernel NULL pointer dereference, address: 0000000000000008
[  732.914815] #PF: supervisor write access in kernel mode
[  732.915731] #PF: error_code(0x0002) - not-present page
[  732.916621] PGD 0 P4D 0
[  732.917072] Oops: 0002 [#1] SMP PTI
[  732.917682] CPU: 7 PID: 0 Comm: swapper/7 Tainted: G           OE     5.4.0-rc7 #1
[  732.918980] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014
[  732.920906] RIP: 0010:dma_fence_signal_locked+0x3e/0x100
[  732.938569] Call Trace:
[  732.939003]  <IRQ>
[  732.939364]  dma_fence_signal+0x29/0x50
[  732.940036]  drm_sched_fence_finished+0x12/0x20 [gpu_sched]
[  732.940996]  drm_sched_process_job+0x34/0xa0 [gpu_sched]
[  732.941910]  dma_fence_signal_locked+0x85/0x100
[  732.942692]  dma_fence_signal+0x29/0x50
[  732.943457]  amdgpu_fence_process+0x99/0x120 [amdgpu]
[  732.944393]  sdma_v4_0_process_trap_irq+0x81/0xa0 [amdgpu]

v2: hold the finished fence at drm_sched_process_job instead of
    amdgpu_fence_process
v3: resume the blank line

Signed-off-by: Yintian Tao <yttao@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/scheduler/sched_main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 3c57e84222ca9..5bb9feddbfd6b 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -632,7 +632,9 @@ static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb)
 
 	trace_drm_sched_process_job(s_fence);
 
+	dma_fence_get(&s_fence->finished);
 	drm_sched_fence_finished(s_fence);
+	dma_fence_put(&s_fence->finished);
 	wake_up_interruptible(&sched->wake_up_worker);
 }
 
-- 
2.20.1


  parent reply	other threads:[~2020-04-07  0:07 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-07  0:00 [PATCH AUTOSEL 5.5 01/35] ARM: dts: sun8i-a83t-tbs-a711: HM5065 doesn't like such a high voltage Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 02/35] bus: sunxi-rsb: Return correct data when mixing 16-bit and 8-bit reads Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 03/35] ARM: dts: Fix dm814x Ethernet by changing to use rgmii-id mode Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 04/35] bpf: Fix deadlock with rq_lock in bpf_send_signal() Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 05/35] net/mlx5e: kTLS, Fix wrong value in record tracker enum Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 06/35] iwlwifi: mvm: take the required lock when clearing time event data Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 07/35] iwlwifi: consider HE capability when setting LDPC Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 08/35] iwlwifi: yoyo: don't add TLV offset when reading FIFOs Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 09/35] iwlwifi: dbg: don't abort if sending DBGC_SUSPEND_RESUME fails Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 10/35] iwlwifi: mvm: Fix rate scale NSS configuration Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 11/35] Input: tm2-touchkey - add support for Coreriver TC360 variant Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 12/35] soc: fsl: dpio: register dpio irq handlers after dpio create Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 13/35] rxrpc: Abstract out the calculation of whether there's Tx space Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 14/35] rxrpc: Fix call interruptibility handling Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 15/35] rxrpc: Fix sendmsg(MSG_WAITALL) handling Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 16/35] net: stmmac: platform: Fix misleading interrupt error msg Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 17/35] net: vxge: fix wrong __VA_ARGS__ usage Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 18/35] ARM: dts: omap4-droid4: Fix lost touchscreen interrupts Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 19/35] riscv: uaccess should be used in nommu mode Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 20/35] hinic: fix a bug of waitting for IO stopped Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 21/35] hinic: fix the bug of clearing event queue Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 22/35] hinic: fix out-of-order excution in arm cpu Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 23/35] hinic: fix wrong para of wait_for_completion_timeout Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 24/35] hinic: fix wrong value of MIN_SKB_LEN Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 25/35] selftests/net: add definition for SOL_DCCP to fix compilation errors for old libc Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 26/35] IB/hfi1: Ensure pq is not left on waitlist Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 27/35] netfilter: nf_tables: Allow set back-ends to report partial overlaps on insertion Sasha Levin
2020-04-07  0:18   ` Stefano Brivio
2020-04-13 16:39     ` Sasha Levin
2020-04-13 20:38       ` Stefano Brivio
2020-04-14 15:08         ` Sasha Levin
2020-04-21 11:32           ` Pablo Neira Ayuso
2020-04-21 13:14             ` Greg KH
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 28/35] netfilter: nft_set_rbtree: Introduce and use nft_rbtree_interval_start() Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 29/35] netfilter: nft_set_rbtree: Detect partial overlaps on insertion Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 30/35] cxgb4/ptp: pass the sign of offset delta in FW CMD Sasha Levin
2020-04-07  0:00 ` Sasha Levin [this message]
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 32/35] cfg80211: Do not warn on same channel at the end of CSA Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 33/35] qlcnic: Fix bad kzalloc null test Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 34/35] i2c: st: fix missing struct parameter description Sasha Levin
2020-04-07  0:00 ` [PATCH AUTOSEL 5.5 35/35] i2c: pca-platform: Use platform_irq_get_optional Sasha Levin

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