[PATCH] kcov: don't instrument lib/find_bit.c
6 views
Skip to first unread message
andrey.k...@linux.dev
Jul 22, 2024, 6:37:32 PM (5 days ago) Jul 22
to Dmitry Vyukov, Andrew Morton, Andrey Konovalov, Aleksandr Nogikh, Marco Elver, Alexander Potapenko, kasa...@googlegroups.com, linu...@kvack.org, Yury Norov, Rasmus Villemoes, linux-...@vger.kernel.org
From: Andrey Konovalov <andre...@gmail.com>
This file produces large amounts of flaky coverage not useful for the
KCOV's intended use case (guiding the fuzzing process).
Signed-off-by: Andrey Konovalov <andre...@gmail.com>
---
I noticed this while running one of the syzkaller's programs.
In one run of the program, the number of KCOV entries amounts to ~300k,
with the top ones:
117285 /home/user/src/lib/find_bit.c:137 (discriminator 10)
116752 /home/user/src/lib/find_bit.c:137 (discriminator 3)
2455 /home/user/src/lib/vsprintf.c:2559
2033 /home/user/src/fs/kernfs/dir.c:317
1662 /home/user/src/fs/kernfs/kernfs-internal.h:72
...
In another run (that triggers exactly the same behavior in the kernel),
the amount of entries drops to ~110k:
7141 /home/user/src/lib/find_bit.c:137 (discriminator 10)
7110 /home/user/src/lib/find_bit.c:137 (discriminator 3)
2455 /home/user/src/lib/vsprintf.c:2559
2033 /home/user/src/fs/kernfs/dir.c:317
1662 /home/user/src/fs/kernfs/kernfs-internal.h:72
...
With this patch applied, the amount of KCOV entries for the same program
remains somewhat stable at ~100k.
---
lib/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/lib/Makefile b/lib/Makefile
index 322bb127b4dc..0fde1c360f32 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -14,6 +14,7 @@ KCOV_INSTRUMENT_list_debug.o := n
KCOV_INSTRUMENT_debugobjects.o := n
KCOV_INSTRUMENT_dynamic_debug.o := n
KCOV_INSTRUMENT_fault-inject.o := n
+KCOV_INSTRUMENT_find_bit.o := n
# string.o implements standard library functions like memset/memcpy etc.
# Use -ffreestanding to ensure that the compiler does not try to "optimize"
--
2.25.1
This file produces large amounts of flaky coverage not useful for the
KCOV's intended use case (guiding the fuzzing process).
Signed-off-by: Andrey Konovalov <andre...@gmail.com>
---
I noticed this while running one of the syzkaller's programs.
In one run of the program, the number of KCOV entries amounts to ~300k,
with the top ones:
117285 /home/user/src/lib/find_bit.c:137 (discriminator 10)
116752 /home/user/src/lib/find_bit.c:137 (discriminator 3)
2455 /home/user/src/lib/vsprintf.c:2559
2033 /home/user/src/fs/kernfs/dir.c:317
1662 /home/user/src/fs/kernfs/kernfs-internal.h:72
...
In another run (that triggers exactly the same behavior in the kernel),
the amount of entries drops to ~110k:
7141 /home/user/src/lib/find_bit.c:137 (discriminator 10)
7110 /home/user/src/lib/find_bit.c:137 (discriminator 3)
2455 /home/user/src/lib/vsprintf.c:2559
2033 /home/user/src/fs/kernfs/dir.c:317
1662 /home/user/src/fs/kernfs/kernfs-internal.h:72
...
With this patch applied, the amount of KCOV entries for the same program
remains somewhat stable at ~100k.
---
lib/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/lib/Makefile b/lib/Makefile
index 322bb127b4dc..0fde1c360f32 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -14,6 +14,7 @@ KCOV_INSTRUMENT_list_debug.o := n
KCOV_INSTRUMENT_debugobjects.o := n
KCOV_INSTRUMENT_dynamic_debug.o := n
KCOV_INSTRUMENT_fault-inject.o := n
+KCOV_INSTRUMENT_find_bit.o := n
# string.o implements standard library functions like memset/memcpy etc.
# Use -ffreestanding to ensure that the compiler does not try to "optimize"
--
2.25.1
Dmitry Vyukov
Jul 23, 2024, 3:56:54 AM (4 days ago) Jul 23
to andrey.k...@linux.dev, Andrew Morton, Andrey Konovalov, Aleksandr Nogikh, Marco Elver, Alexander Potapenko, kasa...@googlegroups.com, linu...@kvack.org, Yury Norov, Rasmus Villemoes, linux-...@vger.kernel.org
On Tue, 23 Jul 2024 at 00:37, <andrey.k...@linux.dev> wrote:
>
> From: Andrey Konovalov <andre...@gmail.com>
>
> This file produces large amounts of flaky coverage not useful for the
> KCOV's intended use case (guiding the fuzzing process).
>
> Signed-off-by: Andrey Konovalov <andre...@gmail.com>
Reviewed-by: Dmitry Vyukov <dvy...@google.com>
>
> From: Andrey Konovalov <andre...@gmail.com>
>
> This file produces large amounts of flaky coverage not useful for the
> KCOV's intended use case (guiding the fuzzing process).
>
> Signed-off-by: Andrey Konovalov <andre...@gmail.com>
> You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+...@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20240722223726.194658-1-andrey.konovalov%40linux.dev.
Reply all
Reply to author
Forward
0 new messages