menu "GCOV-based kernel profiling" config GCOV_KERNEL bool "Enable gcov-based kernel profiling" depends on DEBUG_FS select CONSTRUCTORS if !UML default n ---help--- This option enables gcov-based code profiling (e.g. for code coverage measurements). If unsure, say N. Additionally specify CONFIG_GCOV_PROFILE_ALL=y to get profiling data for the entire kernel. To enable profiling for specific files or directories, add a line similar to the following to the respective Makefile: For a single file (e.g. main.o): GCOV_PROFILE_main.o := y For all files in one directory: GCOV_PROFILE := y To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL is specified, use: GCOV_PROFILE_main.o := n and: GCOV_PROFILE := n Note that the debugfs filesystem has to be mounted to access profiling data. config ARCH_HAS_GCOV_PROFILE_ALL def_bool n config GCOV_PROFILE_ALL bool "Profile entire Kernel" depends on !COMPILE_TEST depends on GCOV_KERNEL depends on ARCH_HAS_GCOV_PROFILE_ALL default n ---help--- This options activates profiling for the entire kernel. If unsure, say N. Note that a kernel compiled with profiling flags will be significantly larger and run slower. Also be sure to exclude files from profiling which are not linked to the kernel image to prevent linker errors. choice prompt "Specify GCOV format" depends on GCOV_KERNEL default GCOV_FORMAT_AUTODETECT ---help--- The gcov format is usually determined by the GCC version, but there are exceptions where format changes are integrated in lower-version GCCs. In such a case use this option to adjust the format used in the kernel accordingly. If unsure, choose "Autodetect". config GCOV_FORMAT_AUTODETECT bool "Autodetect" ---help--- Select this option to use the format that corresponds to your GCC version. config GCOV_FORMAT_3_4 bool "GCC 3.4 format" ---help--- Select this option to use the format defined by GCC 3.4. config GCOV_FORMAT_4_7 bool "GCC 4.7 format" ---help--- Select this option to use the format defined by GCC 4.7. endchoice endmenu get' action='/cgit.cgi/linux/net-next.git/log/sound/soc'>
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authorLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800
commit39cb2c9a316e77f6dfba96c543e55b6672d5a37e (patch)
tree98fe974ee4e20121253de7f61fc8d01bdb3821c1 /sound/soc
parent2c5d9555d6d937966d79d4c6529a5f7b9206e405 (diff)
drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()
I've seen this trigger twice now, where the i915_gem_object_to_ggtt() call in intel_unpin_fb_obj() returns NULL, resulting in an oops immediately afterwards as the (inlined) call to i915_vma_unpin_fence() tries to dereference it. It seems to be some race condition where the object is going away at shutdown time, since both times happened when shutting down the X server. The call chains were different: - VT ioctl(KDSETMODE, KD_TEXT): intel_cleanup_plane_fb+0x5b/0xa0 [i915] drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper] intel_atomic_commit_tail+0x749/0xfe0 [i915] intel_atomic_commit+0x3cb/0x4f0 [i915] drm_atomic_commit+0x4b/0x50 [drm] restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper] drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper] intel_fbdev_set_par+0x18/0x70 [i915] fb_set_var+0x236/0x460 fbcon_blank+0x30f/0x350 do_unblank_screen+0xd2/0x1a0 vt_ioctl+0x507/0x12a0 tty_ioctl+0x355/0xc30 do_vfs_ioctl+0xa3/0x5e0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x13/0x94 - i915 unpin_work workqueue: intel_unpin_work_fn+0x58/0x140 [i915] process_one_work+0x1f1/0x480 worker_thread+0x48/0x4d0 kthread+0x101/0x140 and this patch purely papers over the issue by adding a NULL pointer check and a WARN_ON_ONCE() to avoid the oops that would then generally make the machine unresponsive. Other callers of i915_gem_object_to_ggtt() seem to also check for the returned pointer being NULL and warn about it, so this clearly has happened before in other places. [ Reported it originally to the i915 developers on Jan 8, applying the ugly workaround on my own now after triggering the problem for the second time with no feedback. This is likely to be the same bug reported as https://bugs.freedesktop.org/show_bug.cgi?id=98829 https://bugs.freedesktop.org/show_bug.cgi?id=99134 which has a patch for the underlying problem, but it hasn't gotten to me, so I'm applying the workaround. ] Cc: Daniel Vetter <daniel.vetter@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'sound/soc')