* [PATCH 0/3 v4 bpf-next] bpf: increment and use correct thread iterator
@ 2020-12-18 18:50 Jonathan Lemon
2020-12-18 18:50 ` [PATCH 1/3 v4 bpf-next] bpf: save correct stopping point in file seq iteration Jonathan Lemon
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Jonathan Lemon @ 2020-12-18 18:50 UTC (permalink / raw)
To: netdev, ast, daniel, yhs, bpf; +Cc: kernel-team
From: Jonathan Lemon <bsd@fb.com>
v3->v4:
Split commit into separate patches.
v2->v3:
Add splat to commitlog descriptions
v1->v2
Use Fixes: shas from correct tree
Jonathan Lemon (3):
bpf: save correct stopping point in file seq iteration.
bpf: Use thread_group_leader()
bpf: optimize task iteration
kernel/bpf/task_iter.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--
2.24.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 1/3 v4 bpf-next] bpf: save correct stopping point in file seq iteration.
2020-12-18 18:50 [PATCH 0/3 v4 bpf-next] bpf: increment and use correct thread iterator Jonathan Lemon
@ 2020-12-18 18:50 ` Jonathan Lemon
2020-12-18 21:01 ` Andrii Nakryiko
2020-12-18 18:50 ` [PATCH 2/3 v4 bpf-next] bpf: Use thread_group_leader() Jonathan Lemon
2020-12-18 18:50 ` [PATCH 3/3 v4 bpf-next] bpf: optimize task iteration Jonathan Lemon
2 siblings, 1 reply; 8+ messages in thread
From: Jonathan Lemon @ 2020-12-18 18:50 UTC (permalink / raw)
To: netdev, ast, daniel, yhs, bpf; +Cc: kernel-team
From: Jonathan Lemon <bsd@fb.com>
On some systems, some variant of the following splat is
repeatedly seen. The common factor in all traces seems
to be the entry point to task_file_seq_next(). With the
patch, all warnings go away.
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: \x0926-....: (20992 ticks this GP) idle=d7e/1/0x4000000000000002 softirq=81556231/81556231 fqs=4876
\x09(t=21033 jiffies g=159148529 q=223125)
NMI backtrace for cpu 26
CPU: 26 PID: 2015853 Comm: bpftool Kdump: loaded Not tainted 5.6.13-0_fbk4_3876_gd8d1f9bf80bb #1
Hardware name: Quanta Twin Lakes MP/Twin Lakes Passive MP, BIOS F09_3A12 10/08/2018
Call Trace:
<IRQ>
dump_stack+0x50/0x70
nmi_cpu_backtrace.cold.6+0x13/0x50
? lapic_can_unplug_cpu.cold.30+0x40/0x40
nmi_trigger_cpumask_backtrace+0xba/0xca
rcu_dump_cpu_stacks+0x99/0xc7
rcu_sched_clock_irq.cold.90+0x1b4/0x3aa
? tick_sched_do_timer+0x60/0x60
update_process_times+0x24/0x50
tick_sched_timer+0x37/0x70
__hrtimer_run_queues+0xfe/0x270
hrtimer_interrupt+0xf4/0x210
smp_apic_timer_interrupt+0x5e/0x120
apic_timer_interrupt+0xf/0x20
</IRQ>
RIP: 0010:get_pid_task+0x38/0x80
Code: 89 f6 48 8d 44 f7 08 48 8b 00 48 85 c0 74 2b 48 83 c6 55 48 c1 e6 04 48 29 f0 74 19 48 8d 78 20 ba 01 00 00 00 f0 0f c1 50 20 <85> d2 74 27 78 11 83 c2 01 78 0c 48 83 c4 08 c3 31 c0 48 83 c4 08
RSP: 0018:ffffc9000d293dc8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: ffff888637c05600 RBX: ffffc9000d293e0c RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000550 RDI: ffff888637c05620
RBP: ffffffff8284eb80 R08: ffff88831341d300 R09: ffff88822ffd8248
R10: ffff88822ffd82d0 R11: 00000000003a93c0 R12: 0000000000000001
R13: 00000000ffffffff R14: ffff88831341d300 R15: 0000000000000000
? find_ge_pid+0x1b/0x20
task_seq_get_next+0x52/0xc0
task_file_seq_get_next+0x159/0x220
task_file_seq_next+0x4f/0xa0
bpf_seq_read+0x159/0x390
vfs_read+0x8a/0x140
ksys_read+0x59/0xd0
do_syscall_64+0x42/0x110
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f95ae73e76e
Code: Bad RIP value.
RSP: 002b:00007ffc02c1dbf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000000000170faa0 RCX: 00007f95ae73e76e
RDX: 0000000000001000 RSI: 00007ffc02c1dc30 RDI: 0000000000000007
RBP: 00007ffc02c1ec70 R08: 0000000000000005 R09: 0000000000000006
R10: fffffffffffff20b R11: 0000000000000246 R12: 00000000019112a0
R13: 0000000000000000 R14: 0000000000000007 R15: 00000000004283c0
If unable to obtain the file structure for the current task,
proceed to the next task number after the one returned from
task_seq_get_next(), instead of the next task number from the
original iterator.
Also, save the stopping task number from task_seq_get_next()
on failure in case of restarts.
Fixes: a650da2ee52a ("bpf: Add task and task/file iterator targets")
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
---
kernel/bpf/task_iter.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 0458a40edf10..8033ab19138a 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -158,13 +158,14 @@ task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
if (!curr_task) {
info->task = NULL;
info->files = NULL;
+ info->tid = curr_tid;
return NULL;
}
curr_files = get_files_struct(curr_task);
if (!curr_files) {
put_task_struct(curr_task);
- curr_tid = ++(info->tid);
+ curr_tid = curr_tid + 1;
info->fd = 0;
goto again;
}
--
2.24.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 2/3 v4 bpf-next] bpf: Use thread_group_leader()
2020-12-18 18:50 [PATCH 0/3 v4 bpf-next] bpf: increment and use correct thread iterator Jonathan Lemon
2020-12-18 18:50 ` [PATCH 1/3 v4 bpf-next] bpf: save correct stopping point in file seq iteration Jonathan Lemon
@ 2020-12-18 18:50 ` Jonathan Lemon
2020-12-18 21:02 ` Andrii Nakryiko
2020-12-18 18:50 ` [PATCH 3/3 v4 bpf-next] bpf: optimize task iteration Jonathan Lemon
2 siblings, 1 reply; 8+ messages in thread
From: Jonathan Lemon @ 2020-12-18 18:50 UTC (permalink / raw)
To: netdev, ast, daniel, yhs, bpf; +Cc: kernel-team
From: Jonathan Lemon <bsd@fb.com>
Instead of directly comparing task->tgid and task->pid, use the
thread_group_leader() helper. This helps with readability, and
there should be no functional change.
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
---
kernel/bpf/task_iter.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 8033ab19138a..dc4007f1843b 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -37,7 +37,7 @@ static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
if (!task) {
++*tid;
goto retry;
- } else if (skip_if_dup_files && task->tgid != task->pid &&
+ } else if (skip_if_dup_files && !thread_group_leader(task) &&
task->files == task->group_leader->files) {
put_task_struct(task);
task = NULL;
--
2.24.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 3/3 v4 bpf-next] bpf: optimize task iteration
2020-12-18 18:50 [PATCH 0/3 v4 bpf-next] bpf: increment and use correct thread iterator Jonathan Lemon
2020-12-18 18:50 ` [PATCH 1/3 v4 bpf-next] bpf: save correct stopping point in file seq iteration Jonathan Lemon
2020-12-18 18:50 ` [PATCH 2/3 v4 bpf-next] bpf: Use thread_group_leader() Jonathan Lemon
@ 2020-12-18 18:50 ` Jonathan Lemon
2020-12-18 21:03 ` Andrii Nakryiko
2 siblings, 1 reply; 8+ messages in thread
From: Jonathan Lemon @ 2020-12-18 18:50 UTC (permalink / raw)
To: netdev, ast, daniel, yhs, bpf; +Cc: kernel-team
From: Jonathan Lemon <bsd@fb.com>
Only obtain the task reference count at the end of the RCU section
instead of repeatedly obtaining/releasing it when iterating though
a thread group.
Jump to the correct branch when it is known that the task is NULL.
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
---
kernel/bpf/task_iter.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index dc4007f1843b..598a8d7da5bf 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -33,7 +33,7 @@ static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
pid = find_ge_pid(*tid, ns);
if (pid) {
*tid = pid_nr_ns(pid, ns);
- task = get_pid_task(pid, PIDTYPE_PID);
+ task = pid_task(pid, PIDTYPE_PID);
if (!task) {
++*tid;
goto retry;
@@ -44,6 +44,7 @@ static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
++*tid;
goto retry;
}
+ get_task_struct(task);
}
rcu_read_unlock();
@@ -148,12 +149,12 @@ task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
* it held a reference to the task/files_struct/file.
* Otherwise, it does not hold any reference.
*/
-again:
if (info->task) {
curr_task = info->task;
curr_files = info->files;
curr_fd = info->fd;
} else {
+again:
curr_task = task_seq_get_next(ns, &curr_tid, true);
if (!curr_task) {
info->task = NULL;
--
2.24.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3 v4 bpf-next] bpf: save correct stopping point in file seq iteration.
2020-12-18 18:50 ` [PATCH 1/3 v4 bpf-next] bpf: save correct stopping point in file seq iteration Jonathan Lemon
@ 2020-12-18 21:01 ` Andrii Nakryiko
2020-12-24 1:08 ` Daniel Borkmann
0 siblings, 1 reply; 8+ messages in thread
From: Andrii Nakryiko @ 2020-12-18 21:01 UTC (permalink / raw)
To: Jonathan Lemon
Cc: Networking, Alexei Starovoitov, Daniel Borkmann, Yonghong Song,
bpf, Kernel Team
On Fri, Dec 18, 2020 at 12:47 PM Jonathan Lemon
<jonathan.lemon@gmail.com> wrote:
>
> From: Jonathan Lemon <bsd@fb.com>
>
> On some systems, some variant of the following splat is
> repeatedly seen. The common factor in all traces seems
> to be the entry point to task_file_seq_next(). With the
> patch, all warnings go away.
>
> rcu: INFO: rcu_sched self-detected stall on CPU
> rcu: \x0926-....: (20992 ticks this GP) idle=d7e/1/0x4000000000000002 softirq=81556231/81556231 fqs=4876
> \x09(t=21033 jiffies g=159148529 q=223125)
> NMI backtrace for cpu 26
> CPU: 26 PID: 2015853 Comm: bpftool Kdump: loaded Not tainted 5.6.13-0_fbk4_3876_gd8d1f9bf80bb #1
> Hardware name: Quanta Twin Lakes MP/Twin Lakes Passive MP, BIOS F09_3A12 10/08/2018
> Call Trace:
> <IRQ>
> dump_stack+0x50/0x70
> nmi_cpu_backtrace.cold.6+0x13/0x50
> ? lapic_can_unplug_cpu.cold.30+0x40/0x40
> nmi_trigger_cpumask_backtrace+0xba/0xca
> rcu_dump_cpu_stacks+0x99/0xc7
> rcu_sched_clock_irq.cold.90+0x1b4/0x3aa
> ? tick_sched_do_timer+0x60/0x60
> update_process_times+0x24/0x50
> tick_sched_timer+0x37/0x70
> __hrtimer_run_queues+0xfe/0x270
> hrtimer_interrupt+0xf4/0x210
> smp_apic_timer_interrupt+0x5e/0x120
> apic_timer_interrupt+0xf/0x20
> </IRQ>
> RIP: 0010:get_pid_task+0x38/0x80
> Code: 89 f6 48 8d 44 f7 08 48 8b 00 48 85 c0 74 2b 48 83 c6 55 48 c1 e6 04 48 29 f0 74 19 48 8d 78 20 ba 01 00 00 00 f0 0f c1 50 20 <85> d2 74 27 78 11 83 c2 01 78 0c 48 83 c4 08 c3 31 c0 48 83 c4 08
> RSP: 0018:ffffc9000d293dc8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
> RAX: ffff888637c05600 RBX: ffffc9000d293e0c RCX: 0000000000000000
> RDX: 0000000000000001 RSI: 0000000000000550 RDI: ffff888637c05620
> RBP: ffffffff8284eb80 R08: ffff88831341d300 R09: ffff88822ffd8248
> R10: ffff88822ffd82d0 R11: 00000000003a93c0 R12: 0000000000000001
> R13: 00000000ffffffff R14: ffff88831341d300 R15: 0000000000000000
> ? find_ge_pid+0x1b/0x20
> task_seq_get_next+0x52/0xc0
> task_file_seq_get_next+0x159/0x220
> task_file_seq_next+0x4f/0xa0
> bpf_seq_read+0x159/0x390
> vfs_read+0x8a/0x140
> ksys_read+0x59/0xd0
> do_syscall_64+0x42/0x110
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x7f95ae73e76e
> Code: Bad RIP value.
> RSP: 002b:00007ffc02c1dbf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> RAX: ffffffffffffffda RBX: 000000000170faa0 RCX: 00007f95ae73e76e
> RDX: 0000000000001000 RSI: 00007ffc02c1dc30 RDI: 0000000000000007
> RBP: 00007ffc02c1ec70 R08: 0000000000000005 R09: 0000000000000006
> R10: fffffffffffff20b R11: 0000000000000246 R12: 00000000019112a0
> R13: 0000000000000000 R14: 0000000000000007 R15: 00000000004283c0
>
> If unable to obtain the file structure for the current task,
> proceed to the next task number after the one returned from
> task_seq_get_next(), instead of the next task number from the
> original iterator.
>
> Also, save the stopping task number from task_seq_get_next()
> on failure in case of restarts.
>
> Fixes: a650da2ee52a ("bpf: Add task and task/file iterator targets")
> Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
> ---
LGTM, thanks!
Acked-by: Andrii Nakryiko <andrii@kernel.org>
> kernel/bpf/task_iter.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
> index 0458a40edf10..8033ab19138a 100644
> --- a/kernel/bpf/task_iter.c
> +++ b/kernel/bpf/task_iter.c
> @@ -158,13 +158,14 @@ task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
> if (!curr_task) {
> info->task = NULL;
> info->files = NULL;
> + info->tid = curr_tid;
> return NULL;
> }
>
> curr_files = get_files_struct(curr_task);
> if (!curr_files) {
> put_task_struct(curr_task);
> - curr_tid = ++(info->tid);
> + curr_tid = curr_tid + 1;
> info->fd = 0;
> goto again;
> }
> --
> 2.24.1
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 2/3 v4 bpf-next] bpf: Use thread_group_leader()
2020-12-18 18:50 ` [PATCH 2/3 v4 bpf-next] bpf: Use thread_group_leader() Jonathan Lemon
@ 2020-12-18 21:02 ` Andrii Nakryiko
0 siblings, 0 replies; 8+ messages in thread
From: Andrii Nakryiko @ 2020-12-18 21:02 UTC (permalink / raw)
To: Jonathan Lemon
Cc: Networking, Alexei Starovoitov, Daniel Borkmann, Yonghong Song,
bpf, Kernel Team
On Fri, Dec 18, 2020 at 12:47 PM Jonathan Lemon
<jonathan.lemon@gmail.com> wrote:
>
> From: Jonathan Lemon <bsd@fb.com>
>
> Instead of directly comparing task->tgid and task->pid, use the
> thread_group_leader() helper. This helps with readability, and
> there should be no functional change.
>
> Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
> ---
Acked-by: Andrii Nakryiko <andrii@kernel.org>
> kernel/bpf/task_iter.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
> index 8033ab19138a..dc4007f1843b 100644
> --- a/kernel/bpf/task_iter.c
> +++ b/kernel/bpf/task_iter.c
> @@ -37,7 +37,7 @@ static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
> if (!task) {
> ++*tid;
> goto retry;
> - } else if (skip_if_dup_files && task->tgid != task->pid &&
> + } else if (skip_if_dup_files && !thread_group_leader(task) &&
> task->files == task->group_leader->files) {
> put_task_struct(task);
> task = NULL;
> --
> 2.24.1
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 3/3 v4 bpf-next] bpf: optimize task iteration
2020-12-18 18:50 ` [PATCH 3/3 v4 bpf-next] bpf: optimize task iteration Jonathan Lemon
@ 2020-12-18 21:03 ` Andrii Nakryiko
0 siblings, 0 replies; 8+ messages in thread
From: Andrii Nakryiko @ 2020-12-18 21:03 UTC (permalink / raw)
To: Jonathan Lemon
Cc: Networking, Alexei Starovoitov, Daniel Borkmann, Yonghong Song,
bpf, Kernel Team
On Fri, Dec 18, 2020 at 12:47 PM Jonathan Lemon
<jonathan.lemon@gmail.com> wrote:
>
> From: Jonathan Lemon <bsd@fb.com>
>
> Only obtain the task reference count at the end of the RCU section
> instead of repeatedly obtaining/releasing it when iterating though
> a thread group.
>
> Jump to the correct branch when it is known that the task is NULL.
>
> Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
> ---
Acked-by: Andrii Nakryiko <andrii@kernel.org>
> kernel/bpf/task_iter.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
> index dc4007f1843b..598a8d7da5bf 100644
> --- a/kernel/bpf/task_iter.c
> +++ b/kernel/bpf/task_iter.c
> @@ -33,7 +33,7 @@ static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
> pid = find_ge_pid(*tid, ns);
> if (pid) {
> *tid = pid_nr_ns(pid, ns);
> - task = get_pid_task(pid, PIDTYPE_PID);
> + task = pid_task(pid, PIDTYPE_PID);
> if (!task) {
> ++*tid;
> goto retry;
> @@ -44,6 +44,7 @@ static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
> ++*tid;
> goto retry;
> }
> + get_task_struct(task);
> }
> rcu_read_unlock();
>
> @@ -148,12 +149,12 @@ task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
> * it held a reference to the task/files_struct/file.
> * Otherwise, it does not hold any reference.
> */
> -again:
> if (info->task) {
> curr_task = info->task;
> curr_files = info->files;
> curr_fd = info->fd;
> } else {
> +again:
> curr_task = task_seq_get_next(ns, &curr_tid, true);
> if (!curr_task) {
> info->task = NULL;
> --
> 2.24.1
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3 v4 bpf-next] bpf: save correct stopping point in file seq iteration.
2020-12-18 21:01 ` Andrii Nakryiko
@ 2020-12-24 1:08 ` Daniel Borkmann
0 siblings, 0 replies; 8+ messages in thread
From: Daniel Borkmann @ 2020-12-24 1:08 UTC (permalink / raw)
To: Andrii Nakryiko, Jonathan Lemon
Cc: Networking, Alexei Starovoitov, Yonghong Song, bpf, Kernel Team
On 12/18/20 10:01 PM, Andrii Nakryiko wrote:
> On Fri, Dec 18, 2020 at 12:47 PM Jonathan Lemon
> <jonathan.lemon@gmail.com> wrote:
>>
>> From: Jonathan Lemon <bsd@fb.com>
>>
>> On some systems, some variant of the following splat is
>> repeatedly seen. The common factor in all traces seems
>> to be the entry point to task_file_seq_next(). With the
>> patch, all warnings go away.
>>
>> rcu: INFO: rcu_sched self-detected stall on CPU
>> rcu: \x0926-....: (20992 ticks this GP) idle=d7e/1/0x4000000000000002 softirq=81556231/81556231 fqs=4876
>> \x09(t=21033 jiffies g=159148529 q=223125)
>> NMI backtrace for cpu 26
>> CPU: 26 PID: 2015853 Comm: bpftool Kdump: loaded Not tainted 5.6.13-0_fbk4_3876_gd8d1f9bf80bb #1
>> Hardware name: Quanta Twin Lakes MP/Twin Lakes Passive MP, BIOS F09_3A12 10/08/2018
>> Call Trace:
>> <IRQ>
>> dump_stack+0x50/0x70
>> nmi_cpu_backtrace.cold.6+0x13/0x50
>> ? lapic_can_unplug_cpu.cold.30+0x40/0x40
>> nmi_trigger_cpumask_backtrace+0xba/0xca
>> rcu_dump_cpu_stacks+0x99/0xc7
>> rcu_sched_clock_irq.cold.90+0x1b4/0x3aa
>> ? tick_sched_do_timer+0x60/0x60
>> update_process_times+0x24/0x50
>> tick_sched_timer+0x37/0x70
>> __hrtimer_run_queues+0xfe/0x270
>> hrtimer_interrupt+0xf4/0x210
>> smp_apic_timer_interrupt+0x5e/0x120
>> apic_timer_interrupt+0xf/0x20
>> </IRQ>
>> RIP: 0010:get_pid_task+0x38/0x80
>> Code: 89 f6 48 8d 44 f7 08 48 8b 00 48 85 c0 74 2b 48 83 c6 55 48 c1 e6 04 48 29 f0 74 19 48 8d 78 20 ba 01 00 00 00 f0 0f c1 50 20 <85> d2 74 27 78 11 83 c2 01 78 0c 48 83 c4 08 c3 31 c0 48 83 c4 08
>> RSP: 0018:ffffc9000d293dc8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
>> RAX: ffff888637c05600 RBX: ffffc9000d293e0c RCX: 0000000000000000
>> RDX: 0000000000000001 RSI: 0000000000000550 RDI: ffff888637c05620
>> RBP: ffffffff8284eb80 R08: ffff88831341d300 R09: ffff88822ffd8248
>> R10: ffff88822ffd82d0 R11: 00000000003a93c0 R12: 0000000000000001
>> R13: 00000000ffffffff R14: ffff88831341d300 R15: 0000000000000000
>> ? find_ge_pid+0x1b/0x20
>> task_seq_get_next+0x52/0xc0
>> task_file_seq_get_next+0x159/0x220
>> task_file_seq_next+0x4f/0xa0
>> bpf_seq_read+0x159/0x390
>> vfs_read+0x8a/0x140
>> ksys_read+0x59/0xd0
>> do_syscall_64+0x42/0x110
>> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> RIP: 0033:0x7f95ae73e76e
>> Code: Bad RIP value.
>> RSP: 002b:00007ffc02c1dbf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
>> RAX: ffffffffffffffda RBX: 000000000170faa0 RCX: 00007f95ae73e76e
>> RDX: 0000000000001000 RSI: 00007ffc02c1dc30 RDI: 0000000000000007
>> RBP: 00007ffc02c1ec70 R08: 0000000000000005 R09: 0000000000000006
>> R10: fffffffffffff20b R11: 0000000000000246 R12: 00000000019112a0
>> R13: 0000000000000000 R14: 0000000000000007 R15: 00000000004283c0
>>
>> If unable to obtain the file structure for the current task,
>> proceed to the next task number after the one returned from
>> task_seq_get_next(), instead of the next task number from the
>> original iterator.
>>
>> Also, save the stopping task number from task_seq_get_next()
>> on failure in case of restarts.
>>
>> Fixes: a650da2ee52a ("bpf: Add task and task/file iterator targets")
Commit sha is non-existent, I fixed it up. Took first 2 into bpf given first in
particular is a fix. Please submit 3/3 individually once we synced trees back.
>> Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
>> ---
>
> LGTM, thanks!
>
> Acked-by: Andrii Nakryiko <andrii@kernel.org>
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-12-24 1:09 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-18 18:50 [PATCH 0/3 v4 bpf-next] bpf: increment and use correct thread iterator Jonathan Lemon
2020-12-18 18:50 ` [PATCH 1/3 v4 bpf-next] bpf: save correct stopping point in file seq iteration Jonathan Lemon
2020-12-18 21:01 ` Andrii Nakryiko
2020-12-24 1:08 ` Daniel Borkmann
2020-12-18 18:50 ` [PATCH 2/3 v4 bpf-next] bpf: Use thread_group_leader() Jonathan Lemon
2020-12-18 21:02 ` Andrii Nakryiko
2020-12-18 18:50 ` [PATCH 3/3 v4 bpf-next] bpf: optimize task iteration Jonathan Lemon
2020-12-18 21:03 ` Andrii Nakryiko
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).