James Clark 287e82cf69 coresight: Fix crash when Perf and sysfs modes are used concurrently ... Partially revert the change in commit 6148652807 ("coresight: Enable and disable helper devices adjacent to the path") which changed the bare call from source_ops(csdev)->enable() to coresight_enable_source() for Perf sessions. It was missed that coresight_enable_source() is specifically for the sysfs interface, rather than being a generic call. This interferes with the sysfs reference counting to cause the following crash: $ perf record -e cs_etm/@tmc_etr0/ -C 0 & $ echo 1 > /sys/bus/coresight/devices/tmc_etr0/enable_sink $ echo 1 > /sys/bus/coresight/devices/etm0/enable_source $ echo 0 > /sys/bus/coresight/devices/etm0/enable_source Unable to handle kernel NULL pointer dereference at virtual address 00000000000001d0 Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP ... Call trace: etm4_disable+0x54/0x150 [coresight_etm4x] coresight_disable_source+0x6c/0x98 [coresight] coresight_disable+0x74/0x1c0 [coresight] enable_source_store+0x88/0xa0 [coresight] dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 kernfs_fop_write_iter+0x120/0x1b8 vfs_write+0x2dc/0x3b0 ksys_write+0x70/0x108 __arm64_sys_write+0x24/0x38 invoke_syscall+0x50/0x128 el0_svc_common.constprop.0+0x104/0x130 do_el0_svc+0x40/0xb8 el0_svc+0x2c/0xb8 el0t_64_sync_handler+0xc0/0xc8 el0t_64_sync+0x1a4/0x1a8 Code: d53cd042 91002000 b9402a81 b8626800 (f940ead5) ---[ end trace 0000000000000000 ]--- This commit linked below also fixes the issue, but has unlocked updates to the mode which could potentially race. So until we come up with a more complete solution that takes all locking and interaction between both modes into account, just revert back to the old behavior for Perf. Reported-by: Junhao He <hejunhao3@huawei.com> Closes: https://lore.kernel.org/linux-arm-kernel/20230921132904.60996-1-hejunhao3@huawei.com/ Fixes: 6148652807 ("coresight: Enable and disable helper devices adjacent to the path") Tested-by: Junhao He <hejunhao3@huawei.com> Signed-off-by: James Clark <james.clark@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20231006131452.646721-1-james.clark@arm.com		2023-11-13 09:40:28 +00:00
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coresight	coresight: Fix crash when Perf and sysfs modes are used concurrently	2023-11-13 09:40:28 +00:00
intel_th	Driver core changes for 6.3-rc1	2023-02-24 12:58:55 -08:00
ptt	hwtracing: hisi_ptt: Use pci_dev_id() to simplify the code	2023-08-15 00:45:56 +01:00
stm	- Daniel Verkamp has contributed a memfd series ("mm/memfd: add	2023-02-23 17:09:35 -08:00
Kconfig	hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe Tune and Trace device	2022-09-08 16:26:17 -06:00