summaryrefslogtreecommitdiffstats
path: root/kernel
diff options
context:
space:
mode:
authorAleksandr Nogikh <nogikh@google.com>2022-04-21 16:36:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-04-21 20:01:10 -0700
commitecc04463d1a36f88baa750d45dfb02c364e1fdb1 (patch)
tree2c3ae0ead64f307fa249dae05c7c57fa3296100c /kernel
parent415fccf85920925d23e5358dfb6a64bcf8a6fdd4 (diff)
downloadlinux-ecc04463d1a36f88baa750d45dfb02c364e1fdb1.tar.bz2
kcov: don't generate a warning on vm_insert_page()'s failure
vm_insert_page()'s failure is not an unexpected condition, so don't do WARN_ONCE() in such a case. Instead, print a kernel message and just return an error code. This flaw has been reported under an OOM condition by sysbot [1]. The message is mainly for the benefit of the test log, in this case the fuzzer's log so that humans inspecting the log can figure out what was going on. KCOV is a testing tool, so I think being a little more chatty when KCOV unexpectedly is about to fail will save someone debugging time. We don't want the WARN, because it's not a kernel bug that syzbot should report, and failure can happen if the fuzzer tries hard enough (as above). Link: https://lkml.kernel.org/r/Ylkr2xrVbhQYwNLf@elver.google.com [1] Link: https://lkml.kernel.org/r/20220401182512.249282-1-nogikh@google.com Fixes: b3d7fe86fbd0 ("kcov: properly handle subsequent mmap calls"), Signed-off-by: Aleksandr Nogikh <nogikh@google.com> Acked-by: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Taras Madan <tarasmadan@google.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kcov.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/kcov.c b/kernel/kcov.c
index 475524bd900a..b3732b210593 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -475,8 +475,11 @@ static int kcov_mmap(struct file *filep, struct vm_area_struct *vma)
vma->vm_flags |= VM_DONTEXPAND;
for (off = 0; off < size; off += PAGE_SIZE) {
page = vmalloc_to_page(kcov->area + off);
- if (vm_insert_page(vma, vma->vm_start + off, page))
- WARN_ONCE(1, "vm_insert_page() failed");
+ res = vm_insert_page(vma, vma->vm_start + off, page);
+ if (res) {
+ pr_warn_once("kcov: vm_insert_page() failed\n");
+ return res;
+ }
}
return 0;
exit: