From 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 4 Jun 2020 16:46:04 -0700 Subject: kcov: collect coverage from interrupts This change extends kcov remote coverage support to allow collecting coverage from soft interrupts in addition to kernel background threads. To collect coverage from code that is executed in softirq context, a part of that code has to be annotated with kcov_remote_start/stop() in a similar way as how it is done for global kernel background threads. Then the handle used for the annotations has to be passed to the KCOV_REMOTE_ENABLE ioctl. Internally this patch adjusts the __sanitizer_cov_trace_pc() compiler inserted callback to not bail out when called from softirq context. kcov_remote_start/stop() are updated to save/restore the current per task kcov state in a per-cpu area (in case the softirq came when the kernel was already collecting coverage in task context). Coverage from softirqs is collected into pre-allocated per-cpu areas, whose size is controlled by the new CONFIG_KCOV_IRQ_AREA_SIZE. [andreyknvl@google.com: turn current->kcov_softirq into unsigned int to fix objtool warning] Link: http://lkml.kernel.org/r/841c778aa3849c5cb8c3761f56b87ce653a88671.1585233617.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Signed-off-by: Andrew Morton Reviewed-by: Dmitry Vyukov Cc: Alan Stern Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Greg Kroah-Hartman Cc: Marco Elver Link: http://lkml.kernel.org/r/469bd385c431d050bc38a593296eff4baae50666.1584655448.git.andreyknvl@google.com Signed-off-by: Linus Torvalds --- include/linux/sched.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index 57a5ce9f33c5..c5d96e3e7fff 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1247,6 +1247,9 @@ struct task_struct { /* KCOV sequence number: */ int kcov_sequence; + + /* Collect coverage from softirq context: */ + unsigned int kcov_softirq; #endif #ifdef CONFIG_MEMCG -- cgit