984f37efa3
Deadlock as below is triggered by one CPU holds drvdata->spinlock and calls cti_enable_hw(). Smp_call_function_single() is called in cti_enable_hw() and tries to let another CPU write CTI registers. That CPU is trying to get drvdata->spinlock in cti_cpu_pm_notify() and doesn't response to IPI from smp_call_function_single(). [ 988.335937] CPU: 6 PID: 10258 Comm: sh Tainted: G W L 5.8.0-rc6-mainline-16783-gc38daa79b26b-dirty #1 [ 988.346364] Hardware name: Thundercomm Dragonboard 845c (DT) [ 988.352073] pstate: 20400005 (nzCv daif +PAN -UAO BTYPE=--) [ 988.357689] pc : smp_call_function_single+0x158/0x1b8 [ 988.362782] lr : smp_call_function_single+0x124/0x1b8 ... [ 988.451638] Call trace: [ 988.454119] smp_call_function_single+0x158/0x1b8 [ 988.458866] cti_enable+0xb4/0xf8 [coresight_cti] [ 988.463618] coresight_control_assoc_ectdev+0x6c/0x128 [coresight] [ 988.469855] coresight_enable+0x1f0/0x364 [coresight] [ 988.474957] enable_source_store+0x5c/0x9c [coresight] [ 988.480140] dev_attr_store+0x14/0x28 [ 988.483839] sysfs_kf_write+0x38/0x4c [ 988.487532] kernfs_fop_write+0x1c0/0x2b0 [ 988.491585] vfs_write+0xfc/0x300 [ 988.494931] ksys_write+0x78/0xe0 [ 988.498283] __arm64_sys_write+0x18/0x20 [ 988.502240] el0_svc_common+0x98/0x160 [ 988.506024] do_el0_svc+0x78/0x80 [ 988.509377] el0_sync_handler+0xd4/0x270 [ 988.513337] el0_sync+0x164/0x180 This change write CTI registers directly in cti_enable_hw(). Config->hw_powered has been checked to be true with spinlock holded. CTI is powered and can be programmed until spinlock is released. Fixes: 6a0953ce7de9 ("coresight: cti: Add CPU idle pm notifer to CTI devices") Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org> [Re-ordered variable declaration] Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Link: https://lore.kernel.org/r/20200916191737.4001561-10-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.