From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, andreyknvl@google.com,
dvyukov@google.com, elver@google.com, glider@google.com,
linux-mm@kvack.org, mm-commits@vger.kernel.org,
penguin-kernel@i-love.sakura.ne.jp,
torvalds@linux-foundation.org
Subject: [patch 03/25] kcov: check kcov_softirq in kcov_remote_stop()
Date: Wed, 10 Jun 2020 18:41:28 -0700 [thread overview]
Message-ID: <20200611014128.5iEXzjAG-%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200610184053.3fa7368ab80e23bfd44de71f@linux-foundation.org>
From: Andrey Konovalov <andreyknvl@google.com>
Subject: kcov: check kcov_softirq in kcov_remote_stop()
kcov_remote_stop() should check that the corresponding kcov_remote_start()
actually found the specified remote handle and started collecting
coverage. This is done by checking the per thread kcov_softirq flag.
A particular failure scenario where this was observed involved a softirq
with a remote coverage collection section coming between check_kcov_mode()
and the access to t->kcov_area in __sanitizer_cov_trace_pc(). In that
softirq kcov_remote_start() bailed out after kcov_remote_find() check, but
the matching kcov_remote_stop() didn't check if kcov_remote_start()
succeeded, and overwrote per thread kcov parameters with invalid (zero)
values.
Link: http://lkml.kernel.org/r/fcd1cd16eac1d2c01a66befd8ea4afc6f8d09833.1591576806.git.andreyknvl@google.com
Fixes: 5ff3b30ab57d ("kcov: collect coverage from interrupts")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
kernel/kcov.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
--- a/kernel/kcov.c~kcov-check-kcov_softirq-in-kcov_remote_stop
+++ a/kernel/kcov.c
@@ -427,7 +427,8 @@ void kcov_task_exit(struct task_struct *
* WARN_ON(!kcov->remote && kcov->t != t);
*
* For KCOV_REMOTE_ENABLE devices, the exiting task is either:
- * 2. A remote task between kcov_remote_start() and kcov_remote_stop().
+ *
+ * 1. A remote task between kcov_remote_start() and kcov_remote_stop().
* In this case we should print a warning right away, since a task
* shouldn't be exiting when it's in a kcov coverage collection
* section. Here t points to the task that is collecting remote
@@ -437,7 +438,7 @@ void kcov_task_exit(struct task_struct *
* WARN_ON(kcov->remote && kcov->t != t);
*
* 2. The task that created kcov exiting without calling KCOV_DISABLE,
- * and then again we can make sure that t->kcov->t == t:
+ * and then again we make sure that t->kcov->t == t:
* WARN_ON(kcov->remote && kcov->t != t);
*
* By combining all three checks into one we get:
@@ -764,7 +765,7 @@ static const struct file_operations kcov
* Internally, kcov_remote_start() looks up the kcov device associated with the
* provided handle, allocates an area for coverage collection, and saves the
* pointers to kcov and area into the current task_struct to allow coverage to
- * be collected via __sanitizer_cov_trace_pc()
+ * be collected via __sanitizer_cov_trace_pc().
* In turns kcov_remote_stop() clears those pointers from task_struct to stop
* collecting coverage and copies all collected coverage into the kcov area.
*/
@@ -972,16 +973,25 @@ void kcov_remote_stop(void)
local_irq_restore(flags);
return;
}
- kcov = t->kcov;
- area = t->kcov_area;
- size = t->kcov_size;
- sequence = t->kcov_sequence;
next prev parent reply other threads:[~2020-06-11 1:41 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-11 1:40 incoming Andrew Morton
2020-06-11 1:41 ` [patch 01/25] khugepaged: selftests: fix timeout condition in wait_for_scan() Andrew Morton
2020-06-11 1:41 ` [patch 02/25] scripts/spelling: add a few more typos Andrew Morton
2020-06-11 1:41 ` Andrew Morton [this message]
2020-06-11 1:41 ` [patch 04/25] lib/lz4/lz4_decompress.c: document deliberate use of `&' Andrew Morton
2020-06-11 1:41 ` [patch 05/25] nilfs2: fix null pointer dereference at nilfs_segctor_do_construct() Andrew Morton
2020-06-11 1:41 ` [patch 06/25] checkpatch: correct check for kernel parameters doc Andrew Morton
2020-06-11 1:41 ` [patch 07/25] lib: fix bitmap_parse() on 64-bit big endian archs Andrew Morton
2020-06-11 1:41 ` [patch 08/25] mm/debug_vm_pgtable: fix kernel crash by checking for THP support Andrew Morton
2020-06-11 1:41 ` [patch 09/25] ocfs2: fix spelling mistake and grammar Andrew Morton
2020-06-11 1:41 ` [patch 10/25] mm: add comments on pglist_data zones Andrew Morton
2020-06-11 1:41 ` [patch 11/25] lib: test get_count_order/long in test_bitops.c Andrew Morton
2020-06-11 1:41 ` [patch 12/25] stacktrace: cleanup inconsistent variable type Andrew Morton
2020-06-11 1:41 ` [patch 13/25] kernel: move use_mm/unuse_mm to kthread.c Andrew Morton
2020-06-11 1:42 ` [patch 14/25] " Andrew Morton
2020-06-11 1:42 ` [patch 15/25] kernel: better document the use_mm/unuse_mm API contract Andrew Morton
2020-06-11 1:42 ` [patch 16/25] kernel: set USER_DS in kthread_use_mm Andrew Morton
2020-06-11 1:42 ` [patch 17/25] mm/madvise: pass task and mm to do_madvise Andrew Morton
2020-06-11 1:42 ` [patch 18/25] mm/madvise: introduce process_madvise() syscall: an external memory hinting API Andrew Morton
2020-06-11 1:42 ` [patch 19/25] mm/madvise: check fatal signal pending of target process Andrew Morton
2020-06-11 1:42 ` [patch 20/25] pid: move pidfd_get_pid() to pid.c Andrew Morton
2020-06-11 1:42 ` [patch 21/25] mm/madvise: support both pid and pidfd for process_madvise Andrew Morton
2020-06-11 1:42 ` [patch 22/25] mm/madvise: allow KSM hints for remote API Andrew Morton
2020-06-11 1:42 ` [patch 23/25] mm: support vector address ranges for process_madvise Andrew Morton
2020-06-11 1:42 ` [patch 24/25] mm: use only pidfd for process_madvise syscall Andrew Morton
2020-06-11 1:42 ` [patch 25/25] mm/madvise.c: remove duplicated include Andrew Morton
2020-06-11 5:25 ` [to-be-updated] mm-pass-task-and-mm-to-do_madvise.patch removed from -mm tree Andrew Morton
2020-06-11 5:26 ` [to-be-updated] mm-introduce-external-memory-hinting-api.patch " Andrew Morton
2020-06-11 5:26 ` [to-be-updated] mm-check-fatal-signal-pending-of-target-process.patch " Andrew Morton
2020-06-11 5:26 ` [to-be-updated] pid-move-pidfd_get_pid-function-to-pidc.patch " Andrew Morton
2020-06-11 5:26 ` [to-be-updated] mm-support-both-pid-and-pidfd-for-process_madvise.patch " Andrew Morton
2020-06-11 5:26 ` [to-be-updated] mm-madvise-allow-ksm-hints-for-remote-api.patch " Andrew Morton
2020-06-11 5:26 ` [to-be-updated] mm-support-vector-address-ranges-for-process_madvise.patch " Andrew Morton
2020-06-11 5:26 ` [to-be-updated] mm-use-only-pidfd-for-process_madvise-syscall.patch " Andrew Morton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200611014128.5iEXzjAG-%akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=andreyknvl@google.com \
--cc=dvyukov@google.com \
--cc=elver@google.com \
--cc=glider@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mm-commits@vger.kernel.org \
--cc=penguin-kernel@i-love.sakura.ne.jp \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).