Hi, Petr
On 2020/6/4 16:29, Petr Mladek wrote:
It might cause double unlock (deadlock) on architectures that did not
use NMI to stop the CPUs.
I have created a conservative fix for this problem for SLES, see
https://github.com/openSUSE/kernel-source/blob/SLE15-SP2-UPDATE/patches.suse/printk-pa
Hi, Petr, Jessica and Miroslav
Thank you for your reply
On 2020/6/4 16:57, Petr Mladek wrote:
On Wed 2020-06-03 14:12:00, Cheng Jian wrote:
It is really handful that module symbols can be found already when
the module is MODULE_STATE_COMING state. It is used by livepatching,
ftrace, and maybe
On 2019/9/4 0:05, Valentin Schneider wrote:
On 03/09/2019 16:43, Radim Krčmář wrote:
The paper "The Linux Scheduler: a Decade of Wasted Cores" used several
custom data gathering points to better understand what was going on in
the scheduler.
Red Hat adapted one of them for the tracepoint frame
Hi, Steven
On 2019/5/6 3:34, Steven Rostedt wrote:
Thanks for the patch. There was some race condition that prevented me
from doing this in the first place, but unfortunately, I don't remember
what that was :-/
I'll have to think about this before applying this patch.
Maybe there isn't a rac
On 2019/4/16 11:40, Kees Cook wrote:
On Mon, Apr 15, 2019 at 11:20 AM Paul Moore wrote:
On Mon, Apr 15, 2019 at 11:05 AM Oleg Nesterov wrote:
On 04/15, Paul Moore wrote:
On Mon, Apr 15, 2019 at 9:43 AM Oleg Nesterov wrote:
Well, acct("/proc/self/attr/current") doesn't look like a good id
On 2019/4/15 23:25, Peter Zijlstra wrote:
On Mon, Apr 15, 2019 at 11:20:31PM +0800, chengjian (D) wrote:
Hi, Peter
On 2019/4/15 20:46, Peter Zijlstra wrote:
I write a demo about this, which I described it as overflow.
I'm not saying there's no overflow, I'm saying there
Hi, Peter
On 2019/4/15 20:46, Peter Zijlstra wrote:
I write a demo about this, which I described it as overflow.
#cat test.c
//test.c
#include
#include
#include
#include
int main(void)
{
long a = 1048576 * 9144968455305; /* shares = tg_shares * load */
unsigned long b = a;
//
Hi.
syzkaller reported the following BUG:
[ 73.146973] kernel BUG at kernel/cred.c:434!
[ 73.150231] invalid opcode: [#1] SMP KASAN PTI
[ 73.151928] CPU: 2 PID: 4058 Comm: syz-executor.6 Not tainted
5.1.0-rc4-00062-g2d06b235815e-dirty #2
[ 73.155174] Hardware name: QEMU Standard P
On 2019/3/13 22:49, luca abeni wrote:
Hi,
After looking at the patch a little bit more and running some tests,
I suspect this solution might be racy:
when the timer is already active, (and hrtimer_start() fails), it
relies on its handler to decrease the running bw (by setting
dl_non_contending
Hi.
When looking to test SCHED_DEADLINE syzkaller report an warn in
task_non_contending(). I tested the mainline kernel with the C program
and captured the same call trace.
[The previous message contains some strings in other formats,
making the mail less readable. So I resend it. SORRY.]
[
Hi Alexander,
I have tested the new version, and put it in
the syzkaller workspace, it works well now.
Tested-by: Cheng Jian
Thanks a lot for taking the time and providing all the details. Please
find an updated version below, which should not exhibit that warning.
Thanks.
Hi，Jiri
This patch should be merged into 4.4 stable,
which still use klp_write_module_reloc.
https://elixir.bootlin.com/linux/v4.4.174/source/arch/x86/kernel/livepatch.c
ZeFeng may have sent a stable(4.4-y) patch to the wrong mail-list(mainline).
Thanks.
On 2019/2/15 15:28, Jiri Kosina w
Hi, Milian
On 2018/1/16 22:33, Milian Wolff wrote:
perf script print the same wakeup_new event multiple times.
These events which trigger this issue all specify a target process.
commit e6dab5ffab59 ("perf/trace: Add ability to set a target task
for events") has designed a method to trace thes
On 2018/1/15 20:31, Peter Zijlstra wrote:
I'm sorry I gave an inappropriate example to make the phenomenon look
confusing.
These events are registered per_cpu and attach in the the
perf_event_ctxp of task too.
So the same event is placed in the process context CPU times.
perf record -e sch
Hi
The demo is like:
#include
#include
#include
#include
#include
static int data_size=0;
module_param(data_size, int, 0644);
static struct kretprobe rp;
static int ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
{
printk(KERN_DEBUG "ret_handler\n");
return 0;
}
On 2017/12/7 5:40, Peter Zijlstra wrote:
@@ -3262,6 +3262,8 @@ static int futex_wait_requeue_pi(u32 __user
*uaddr, unsigned int flags,
SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head,
size_t, len)
{
+ unsigned long address = (unsigned long)head
Hi, all.
On 2017/10/20 0:53, Will Deacon wrote:
I've not had any more feedback on this and the testing results are very
encouraging so I'd like to merge it for 4.15. However, it might make more
sense for the whole thing to go via -tip instead.
Ingo, Peter: what do you prefer?
Will
Will Deac
On 2017/10/25 10:23, Namhyung Kim wrote:
On Tue, Oct 24, 2017 at 10:46:44AM -0300, Arnaldo Carvalho de Melo wrote:
Em Tue, Oct 24, 2017 at 03:45:34PM +0800, Cheng Jian escreveu:
When running perf sched record, there is a bug.
It's system_wide when we specify a command line.
Humm, isn't this
On 2017/10/16 23:30, Will Deacon wrote:
Can you jump the PC once the child appears to be "stuck"?
IIRC, GDB has special heuristics to step through LDXR/STXR critical
sections.
The function can be returned, But the number of instructions looks too much
We use objdump to count the assembly code
Hi
I write demo use ptrace/SINGLESTEP to count the number of instructions
executed by the process
The parent process fork+exec a child process, and trace(SINGLESTEP) it,
It works fine under the x86_64 architecture but has an exception under
arm64.
```cpp
//demo.c
#include
#include
#include
On 2017/10/10 19:33, Peter Zijlstra wrote:
No, this _cannot_ be right. The whole point of the @task argument was to
deliver the event multiple times -- maybe not to the same event, but it
needs to be delivered multiple times in some cases. Therefore this is
broken.
But now you've got me looking
On 2017/9/6 16:36, Thomas Gleixner write:
Ok. Still that patch has issues.
1) It's white space damaged. Please use TAB not spaces for
indentation. checkpatch.pl would have told you.
2) Why are you using _cond_resched() instead of plain cond_resched().
cond_resched() is what you want to
diff --git a/kernel/futex.c b/kernel/futex.c
index 3d38eaf..0b2d17a 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1545,6 +1545,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval,
struct futex_pi_state *pi_
spin_unlock(&hb->lock);
wake_up_q(&wake_q);
+_cond_res
Hi Mark,
OK, I will do it now
On Tue, Sep 05, 2017 at 10:28:38AM +0800, chengjian c00427203 wrote:
Convert pr_warning to standard pr_warn in arch/arm64/kernel/smp.c
Signed-off-by: Cheng Jian
---
arch/arm64/kernel/smp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Is this a
A competition happend when some thread use pthread_mutex(futex in
kernel). I make a demo about this : two thread get a lock and then sleep
for a few time, finally unlock when waked up.
```cpp
pthread_mutex_lock(&mutex);
//printf("tid = %lu, count = %d\n", pthread_self( ), i);
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