[PATCH AUTOSEL 5.4 275/330] coresight: etm4x: Fix use-after-free of per-cpu etm drvdata

Sasha Levin
2020-09-18T02:56:47Z

From: Suzuki K Poulose <suzuki.poulose@arm.com>

[ Upstream commit 3f4943d422c5febbb3c764670011a00eb2a86238 ]

etm probe could be deferred due to the dependency in the trace
path chain and may be retried. We need to clear the per-cpu
etmdrvdata entry for the etm in case of a failure to avoid
use-after-free cases as reported below:

KASAN use-after-free bug in etm4_cpu_pm_notify():

[ 8.574566] coresight etm0: CPU0: ETM v4.2 initialized
[ 8.581920] BUG: KASAN: use-after-free in etm4_cpu_pm_notify+0x580/0x2024
[ 8.581925] Read of size 8 at addr ffffff813304f8c8 by task swapper/3/0
[ 8.581927]
[ 8.581934] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G S W 5.4.28 #314
[ 8.587775] coresight etm1: CPU1: ETM v4.2 initialized
[ 8.594195] Call trace:
[ 8.594205] dump_backtrace+0x0/0x188
[ 8.594209] show_stack+0x20/0x2c
[ 8.594216] dump_stack+0xdc/0x144
[ 8.594227] print_address_description+0x3c/0x494
[ 8.594232] __kasan_report+0x144/0x168
[ 8.601598] coresight etm2: CPU2: ETM v4.2 initialized
[ 8.602563] kasan_report+0x10/0x18
[ 8.602568] check_memory_region+0x1a4/0x1b4
[ 8.602572] __kasan_check_read+0x18/0x24
[ 8.602577] etm4_cpu_pm_notify+0x580/0x2024
[ 8.665945] notifier_call_chain+0x5c/0x90
[ 8.670166] __atomic_notifier_call_chain+0x90/0xf8
[ 8.675182] cpu_pm_notify+0x40/0x6c
[ 8.678858] cpu_pm_enter+0x38/0x80
[ 8.682451] psci_enter_idle_state+0x34/0x70
[ 8.686844] cpuidle_enter_state+0xb8/0x20c
[ 8.691143] cpuidle_enter+0x38/0x4c
[ 8.694820] call_cpuidle+0x3c/0x68
[ 8.698408] do_idle+0x1a0/0x280
[ 8.701729] cpu_startup_entry+0x24/0x28
[ 8.705768] secondary_start_kernel+0x15c/0x170
[ 8.710423]
[ 8.711972] Allocated by task 242:
[ 8.715473] __kasan_kmalloc+0xf0/0x1ac
[ 8.719426] kasan_slab_alloc+0x14/0x1c
[ 8.723375] __kmalloc_track_caller+0x23c/0x388
[ 8.728040] devm_kmalloc+0x38/0x94
[ 8.731632] etm4_probe+0x48/0x3c8
[ 8.735140] amba_probe+0xbc/0x158
[ 8.738645] really_probe+0x144/0x408
[ 8.742412] driver_probe_device+0x70/0x140
[ 8.746716] __device_attach_driver+0x9c/0x110
[ 8.751287] bus_for_each_drv+0x90/0xd8
[ 8.755236] __device_attach+0xb4/0x164
[ 8.759188] device_initial_probe+0x20/0x2c
[ 8.763490] bus_probe_device+0x34/0x94
[ 8.767436] device_add+0x34c/0x3e0
[ 8.771029] amba_device_try_add+0x68/0x440
[ 8.775332] amba_deferred_retry_func+0x48/0xc8
[ 8.779997] process_one_work+0x344/0x648
[ 8.784127] worker_thread+0x2ac/0x47c
[ 8.787987] kthread+0x128/0x138
[ 8.791313] ret_from_fork+0x10/0x18
[ 8.794993]
[ 8.796532] Freed by task 242:
[ 8.799684] __kasan_slab_free+0x15c/0x22c
[ 8.803897] kasan_slab_free+0x10/0x1c
[ 8.807761] kfree+0x25c/0x4bc
[ 8.810913] release_nodes+0x240/0x2b0
[ 8.814767] devres_release_all+0x3c/0x54
[ 8.818887] really_probe+0x178/0x408
[ 8.822661] driver_probe_device+0x70/0x140
[ 8.826963] __device_attach_driver+0x9c/0x110
[ 8.831539] bus_for_each_drv+0x90/0xd8
[ 8.835487] __device_attach+0xb4/0x164
[ 8.839431] device_initial_probe+0x20/0x2c
[ 8.843732] bus_probe_device+0x34/0x94
[ 8.847678] device_add+0x34c/0x3e0
[ 8.851274] amba_device_try_add+0x68/0x440
[ 8.855576] amba_deferred_retry_func+0x48/0xc8
[ 8.860240] process_one_work+0x344/0x648
[ 8.864366] worker_thread+0x2ac/0x47c
[ 8.868228] kthread+0x128/0x138
[ 8.871557] ret_from_fork+0x10/0x18
[ 8.875231]
[ 8.876782] The buggy address belongs to the object at ffffff813304f800
[ 8.876782] which belongs to the cache kmalloc-1k of size 1024
[ 8.889632] The buggy address is located 200 bytes inside of
[ 8.889632] 1024-byte region [ffffff813304f800, ffffff813304fc00)
[ 8.901761] The buggy address belongs to the page:
[ 8.906695] page:ffffffff04ac1200 refcount:1 mapcount:0 mapping:ffffff8146c03800 index:0x0 compound_mapcount: 0
[ 8.917047] flags: 0x4000000000010200(slab|head)
[ 8.921799] raw: 4000000000010200 dead000000000100 dead000000000122 ffffff8146c03800
[ 8.929753] raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
[ 8.937703] page dumped because: kasan: bad access detected
[ 8.943433]
[ 8.944974] Memory state around the buggy address:
[ 8.949903] ffffff813304f780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 8.957320] ffffff813304f800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 8.964742] >ffffff813304f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 8.972157] ^
[ 8.977886] ffffff813304f900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 8.985298] ffffff813304f980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 8.992713] ==================================================================

Fixes: f188b5e76aae ("coresight: etm4x: Save/restore state across CPU low power states")
Reported-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-22-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwtracing/coresight/coresight-etm4x.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index a128b5063f46c..83dccdeef9069 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -1184,6 +1184,7 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
return 0;

err_arch_supported:
+ etmdrvdata[drvdata->cpu] = NULL;
if (--etm4_count == 0) {
cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);
if (hp_online)
--
2.25.1