0c32b8ec02
Interrupt routine must wake process waiting for given interrupt AFTER updating driver's internal structures and contexts. Doing it in-between is a serious bug. This patch moves all calls to the wake() function to the end of the interrupt processing block to avoid potential and real races, especially on multi-core platforms. This also fixes following issue reported from clock core (clocks were disabled in interrupt after being unprepared from the other place in the driver, the stack trace however points to the different place than s5p_mfc driver because of the race): WARNING: CPU: 1 PID: 18 at drivers/clk/clk.c:544 clk_core_unprepare+0xc8/0x108 Modules linked in: CPU: 1 PID: 18 Comm: kworker/1:0 Not tainted 4.10.0-next-20170223-00070-g04e18bc99ab9-dirty #2154 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) Workqueue: pm pm_runtime_work [<c010d8b0>] (unwind_backtrace) from [<c010a534>] (show_stack+0x10/0x14) [<c010a534>] (show_stack) from [<c033292c>] (dump_stack+0x74/0x94) [<c033292c>] (dump_stack) from [<c011cef4>] (__warn+0xd4/0x100) [<c011cef4>] (__warn) from [<c011cf40>] (warn_slowpath_null+0x20/0x28) [<c011cf40>] (warn_slowpath_null) from [<c0387a84>] (clk_core_unprepare+0xc8/0x108) [<c0387a84>] (clk_core_unprepare) from [<c0389d84>] (clk_unprepare+0x24/0x2c) [<c0389d84>] (clk_unprepare) from [<c03d4660>] (exynos_sysmmu_suspend+0x48/0x60) [<c03d4660>] (exynos_sysmmu_suspend) from [<c042b9b0>] (pm_generic_runtime_suspend+0x2c/0x38) [<c042b9b0>] (pm_generic_runtime_suspend) from [<c0437580>] (genpd_runtime_suspend+0x94/0x220) [<c0437580>] (genpd_runtime_suspend) from [<c042e240>] (__rpm_callback+0x134/0x208) [<c042e240>] (__rpm_callback) from [<c042e334>] (rpm_callback+0x20/0x80) [<c042e334>] (rpm_callback) from [<c042d3b8>] (rpm_suspend+0xdc/0x458) [<c042d3b8>] (rpm_suspend) from [<c042ea24>] (pm_runtime_work+0x80/0x90) [<c042ea24>] (pm_runtime_work) from [<c01322c4>] (process_one_work+0x120/0x318) [<c01322c4>] (process_one_work) from [<c0132520>] (worker_thread+0x2c/0x4ac) [<c0132520>] (worker_thread) from [<c0137ab0>] (kthread+0xfc/0x134) [<c0137ab0>] (kthread) from [<c0107978>] (ret_from_fork+0x14/0x3c) ---[ end trace 1ead49a7bb83f0d8 ]--- Fixes: af93574678108 ("[media] MFC: Add MFC 5.1 V4L2 driver") Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> CC: stable@vger.kernel.org # v4.5+ Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.