The following commit has been merged into the timers/urgent branch of tip:
Commit-ID: 4e8c11b6b3f0b6a283e898344f154641eda94266
Gitweb: https://git.kernel.org/tip/4e8c11b6b3f0b6a283e898344f154641eda94266
Author: Yu Liao <liaoyu15(a)huawei.com>
AuthorDate: Mon, 13 Dec 2021 21:57:27 +08:00
Committer: Thomas Gleixner <tglx(a)linutronix.de>
CommitterDate: Fri, 17 Dec 2021 23:06:22 +01:00
timekeeping: Really make sure wall_to_monotonic isn't positive
Even after commit e1d7ba873555 ("time: Always make sure wall_to_monotonic
isn't positive") it is still possible to make wall_to_monotonic positive
by running the following code:
int main(void)
{
struct timespec time;
clock_gettime(CLOCK_MONOTONIC, &time);
time.tv_nsec = 0;
clock_settime(CLOCK_REALTIME, &time);
return 0;
}
The reason is that the second parameter of timespec64_compare(), ts_delta,
may be unnormalized because the delta is calculated with an open coded
substraction which causes the comparison of tv_sec to yield the wrong
result:
wall_to_monotonic = { .tv_sec = -10, .tv_nsec = 900000000 }
ts_delta = { .tv_sec = -9, .tv_nsec = -900000000 }
That makes timespec64_compare() claim that wall_to_monotonic < ts_delta,
but actually the result should be wall_to_monotonic > ts_delta.
After normalization, the result of timespec64_compare() is correct because
the tv_sec comparison is not longer misleading:
wall_to_monotonic = { .tv_sec = -10, .tv_nsec = 900000000 }
ts_delta = { .tv_sec = -10, .tv_nsec = 100000000 }
Use timespec64_sub() to ensure that ts_delta is normalized, which fixes the
issue.
Fixes: e1d7ba873555 ("time: Always make sure wall_to_monotonic isn't positive")
Signed-off-by: Yu Liao <liaoyu15(a)huawei.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: stable(a)vger.kernel.org
Link: https://lore.kernel.org/r/20211213135727.1656662-1-liaoyu15@huawei.com
---
kernel/time/timekeeping.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index b348749..dcdcb85 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1306,8 +1306,7 @@ int do_settimeofday64(const struct timespec64 *ts)
timekeeping_forward_now(tk);
xt = tk_xtime(tk);
- ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
- ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
+ ts_delta = timespec64_sub(*ts, xt);
if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
ret = -EINVAL;
We found an abnormally high latency when executing modprobe raid6_pq, the
latency is greater than 1.2s when CONFIG_PREEMPT_VOLUNTARY=y, greater than
67ms when CONFIG_PREEMPT=y, and greater than 16ms when CONFIG_PREEMPT_RT=y.
How to reproduce:
- Install cyclictest
sudo apt install rt-tests
- Run cyclictest example in one terminal
sudo cyclictest -S -p 95 -d 0 -i 1000 -D 24h -m
- Modprobe raid6_pq in another terminal
sudo modprobe raid6_pq
This is caused by ksoftirqd fail to scheduled due to disable preemption,
this time is too long and unreasonable.
Reduce high latency by using migrate_disabl()/emigrate_enable() instead of
preempt_disable()/preempt_enable(), the latency won't greater than 100us.
This patch beneficial for CONFIG_PREEMPT=y or CONFIG_PREEMPT_RT=y, but no
effect for CONFIG_PREEMPT_VOLUNTARY=y.
Cc: stable(a)vger.kernel.org
Fixes: fe5cbc6e06c7 ("md/raid6 algorithms: delta syndrome functions")
Fixes: cc4589ebfae6 ("Rename raid6 files now they're in a 'raid6' directory.")
Link: https://lore.kernel.org/linux-raid/b06c5e3ef3413f12a2c2b2a241005af9@linux.d… # v1
Signed-off-by: Yajun Deng <yajun.deng(a)linux.dev>
---
lib/raid6/algos.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c
index 6d5e5000fdd7..21611d05c34c 100644
--- a/lib/raid6/algos.c
+++ b/lib/raid6/algos.c
@@ -162,7 +162,7 @@ static inline const struct raid6_calls *raid6_choose_gen(
perf = 0;
- preempt_disable();
+ migrate_disable();
j0 = jiffies;
while ((j1 = jiffies) == j0)
cpu_relax();
@@ -171,7 +171,7 @@ static inline const struct raid6_calls *raid6_choose_gen(
(*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs);
perf++;
}
- preempt_enable();
+ migrate_enable();
if (perf > bestgenperf) {
bestgenperf = perf;
@@ -186,7 +186,7 @@ static inline const struct raid6_calls *raid6_choose_gen(
perf = 0;
- preempt_disable();
+ migrate_disable();
j0 = jiffies;
while ((j1 = jiffies) == j0)
cpu_relax();
@@ -196,7 +196,7 @@ static inline const struct raid6_calls *raid6_choose_gen(
PAGE_SIZE, *dptrs);
perf++;
}
- preempt_enable();
+ migrate_enable();
if (best == *algo)
bestxorperf = perf;
--
2.32.0
mount.cifs can pass a device with multiple delimiters in it. This will
cause rename(2) to fail with ENOENT.
V2:
- Make sanitize_path more readable.
- Fix multiple delimiters between UNC and prepath.
- Avoid a memory leak if a bad user starts putting a lot of delimiters
in the path on purpose.
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=2031200
Fixes: 24e0a1eff9e2 ("cifs: switch to new mount api")
Cc: stable(a)vger.kernel.org # 5.11+
Signed-off-by: Thiago Rafael Becker <trbecker(a)gmail.com>
---
fs/cifs/fs_context.c | 38 +++++++++++++++++++++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)
diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
index 6a179ae753c1..e3ed25dc6f3f 100644
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -434,6 +434,42 @@ int smb3_parse_opt(const char *options, const char *key, char **val)
return rc;
}
+/*
+ * Remove duplicate path delimiters. Windows is supposed to do that
+ * but there are some bugs that prevent rename from working if there are
+ * multiple delimiters.
+ *
+ * Returns a sanitized duplicate of @path. The caller is responsible for
+ * cleaning up the original.
+ */
+#define IS_DELIM(c) ((c) == '/' || (c) == '\\')
+static char *sanitize_path(char *path)
+{
+ char *cursor1 = path, *cursor2 = path;
+
+ /* skip all prepended delimiters */
+ while (IS_DELIM(*cursor1))
+ cursor1++;
+
+ /* copy the first letter */
+ *cursor2 = *cursor1;
+
+ /* copy the remainder... */
+ while (*(cursor1++)) {
+ /* ... skipping all duplicated delimiters */
+ if (IS_DELIM(*cursor1) && IS_DELIM(*cursor2))
+ continue;
+ *(++cursor2) = *cursor1;
+ }
+
+ /* if the last character is a delimiter, skip it */
+ if (IS_DELIM(*(cursor2 - 1)))
+ cursor2--;
+
+ *(cursor2) = '\0';
+ return kstrdup(path, GFP_KERNEL);
+}
+
/*
* Parse a devname into substrings and populate the ctx->UNC and ctx->prepath
* fields with the result. Returns 0 on success and an error otherwise
@@ -493,7 +529,7 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx)
if (!*pos)
return 0;
- ctx->prepath = kstrdup(pos, GFP_KERNEL);
+ ctx->prepath = sanitize_path(pos);
if (!ctx->prepath)
return -ENOMEM;
--
2.31.1