July 2024 - Linux-kselftest-mirror

[PATCH v2] kselftests: dmabuf-heaps: Ensure the driver name is null-terminated

by Zenghui Yu

Even if a vgem device is configured in, we will skip the import_vgem_fd() test almost every time. TAP version 13 1..11 # Testing heap: system # ======================================= # Testing allocation and importing: ok 1 # SKIP Could not open vgem -1 The problem is that we use the DRM_IOCTL_VERSION ioctl to query the driver version information but leave the name field a non-null-terminated string. Terminate it properly to actually test against the vgem device. While at it, let's check the length of the driver name is exactly 4 bytes and return early otherwise (in case there is a name like "vgemfoo" that gets converted to "vgem\0" unexpectedly). Signed-off-by: Zenghui Yu <yuzenghui(a)huawei.com> --- * From v1 [1]: - Check version.name_len is exactly 4 bytes and return early otherwise [1] https://lore.kernel.org/r/20240708134654.1725-1-yuzenghui@huawei.com P.S., Maybe worth including the kselftests file into "DMA-BUF HEAPS FRAMEWORK" MAINTAINERS entry? tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c index 5f541522364f..5d0a809dc2df 100644 --- a/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c +++ b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c @@ -29,9 +29,11 @@ static int check_vgem(int fd) version.name = name; ret = ioctl(fd, DRM_IOCTL_VERSION, &version); - if (ret) + if (ret || version.name_len != 4) return 0; + name[4] = '\0'; + return !strcmp(name, "vgem"); } -- 2.33.0

8 months, 3 weeks

2
2
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[PATCH v8 4/5] KVM: riscv: selftests: Fix compile error

by Yong-Xuan Wang

Fix compile error introduced by commit d27c34a73514 ("KVM: riscv: selftests: Add some Zc* extensions to get-reg-list test"). These 4 lines should be end with ";". Fixes: d27c34a73514 ("KVM: riscv: selftests: Add some Zc* extensions to get-reg-list test") Signed-off-by: Yong-Xuan Wang <yongxuan.wang(a)sifive.com> --- tools/testing/selftests/kvm/riscv/get-reg-list.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/kvm/riscv/get-reg-list.c b/tools/testing/selftests/kvm/riscv/get-reg-list.c index f92c2fb23fcd..8e34f7fa44e9 100644 --- a/tools/testing/selftests/kvm/riscv/get-reg-list.c +++ b/tools/testing/selftests/kvm/riscv/get-reg-list.c @@ -961,10 +961,10 @@ KVM_ISA_EXT_SIMPLE_CONFIG(zbkb, ZBKB); KVM_ISA_EXT_SIMPLE_CONFIG(zbkc, ZBKC); KVM_ISA_EXT_SIMPLE_CONFIG(zbkx, ZBKX); KVM_ISA_EXT_SIMPLE_CONFIG(zbs, ZBS); -KVM_ISA_EXT_SIMPLE_CONFIG(zca, ZCA), -KVM_ISA_EXT_SIMPLE_CONFIG(zcb, ZCB), -KVM_ISA_EXT_SIMPLE_CONFIG(zcd, ZCD), -KVM_ISA_EXT_SIMPLE_CONFIG(zcf, ZCF), +KVM_ISA_EXT_SIMPLE_CONFIG(zca, ZCA); +KVM_ISA_EXT_SIMPLE_CONFIG(zcb, ZCB); +KVM_ISA_EXT_SIMPLE_CONFIG(zcd, ZCD); +KVM_ISA_EXT_SIMPLE_CONFIG(zcf, ZCF); KVM_ISA_EXT_SIMPLE_CONFIG(zcmop, ZCMOP); KVM_ISA_EXT_SIMPLE_CONFIG(zfa, ZFA); KVM_ISA_EXT_SIMPLE_CONFIG(zfh, ZFH); -- 2.17.1

8 months, 3 weeks

3
2
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[PATCH 0/1] Add KUnit tests for llist

by Artur Alves

Hi all, This is part of a hackathon organized by LKCAMP[1], focused on writing tests using KUnit. We reached out a while ago asking for advice on what would be a useful contribution[2] and ended up choosing data structures that did not yet have tests. This patch adds tests for the llist data structure, defined in include/linux/llist.h, and is inspired by the KUnit tests for the doubly linked list in lib/list-test.c[3]. [1] https://lkcamp.dev/about/ [2] https://lore.kernel.org/all/Zktnt7rjKryTh9-N@arch/ [3] https://elixir.bootlin.com/linux/latest/source/lib/list-test.c Artur Alves (1): lib/llist_kunit.c: add KUnit tests for llist lib/Kconfig.debug | 11 ++ lib/Makefile | 1 + lib/llist_kunit.c | 360 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 372 insertions(+) create mode 100644 lib/llist_kunit.c -- 2.45.2

8 months, 3 weeks

2
3
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[PATCH 0/4] Introduce userspace-driven ALSA timers

by Ivan Orlov

There are multiple possible timer sources which could be useful for the sound stream synchronization: hrtimers, hardware clocks (e.g. PTP), timer wheels (jiffies). Currently, using one of them to synchronize the audio stream of snd-aloop module would require writing a kernel-space driver which exports an ALSA timer through the snd_timer interface. However, it is not really convenient for application developers, who may want to define their custom timer sources for audio synchronization. For instance, we could have a network application which receives frames and sends them to snd-aloop pcm device, and another application listening on the other end of snd-aloop. It makes sense to transfer a new period of data only when certain amount of frames is received through the network, but definitely not when a certain amount of jiffies on a local system elapses. Since all of the devices are purely virtual it won't introduce any glitches and will help the application developers to avoid using sample-rate conversion. This patch series introduces userspace-driven ALSA timers: virtual timers which are created and controlled from userspace. The timer can be created from the userspace using the new ioctl SNDRV_TIMER_IOCTL_CREATE. After creating a timer, it becomes available for use system-wide, so it can be passed to snd-aloop as a timer source (timer_source parameter would be "-1.SNDRV_TIMER_GLOBAL_UDRIVEN.{timer_id}"). When the userspace app decides to trigger a timer, it calls another ioctl SNDRV_TIMER_IOCTL_TRIGGER on the file descriptor of a timer. It initiates a transfer of a new period of data. Userspace-driven timers are associated with file descriptors. If the application wishes to destroy the timer, it can simply release the file descriptor of a virtual timer. I believe introducing new ioctl calls is quite inconvenient (as we have a limited amount of them), but other possible ways of app <-> kernel communication (like virtual FS) seem completely inappropriate for this task (but I'd love to discuss alternative solutions). This patch series also updates the snd-aloop module so the global timers can be used as a timer_source for it (it allows using userspace-driven timers as timer source). Ivan Orlov (4): ALSA: aloop: Allow using global timers Docs/sound: Add documentation for userspace-driven ALSA timers ALSA: timer: Introduce virtual userspace-driven timers selftests: ALSA: Cover userspace-driven timers with test Documentation/sound/index.rst | 1 + Documentation/sound/utimers.rst | 120 +++++++++++ include/uapi/sound/asound.h | 17 ++ sound/core/Kconfig | 11 + sound/core/timer.c | 226 ++++++++++++++++++++ sound/drivers/aloop.c | 2 + tools/testing/selftests/alsa/Makefile | 2 +- tools/testing/selftests/alsa/global-timer.c | 87 ++++++++ tools/testing/selftests/alsa/utimer-test.c | 133 ++++++++++++ 9 files changed, 598 insertions(+), 1 deletion(-) create mode 100644 Documentation/sound/utimers.rst create mode 100644 tools/testing/selftests/alsa/global-timer.c create mode 100644 tools/testing/selftests/alsa/utimer-test.c -- 2.34.1

8 months, 3 weeks

3
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[PATCH AUTOSEL 5.4 2/6] selftests/bpf: Fix send_signal test with nested CONFIG_PARAVIRT

by Sasha Levin

From: Yonghong Song <yonghong.song(a)linux.dev> [ Upstream commit 7015843afcaf68c132784c89528dfddc0005e483 ] Alexei reported that send_signal test may fail with nested CONFIG_PARAVIRT configs. In this particular case, the base VM is AMD with 166 cpus, and I run selftests with regular qemu on top of that and indeed send_signal test failed. I also tried with an Intel box with 80 cpus and there is no issue. The main qemu command line includes: -enable-kvm -smp 16 -cpu host The failure log looks like: $ ./test_progs -t send_signal [ 48.501588] watchdog: BUG: soft lockup - CPU#9 stuck for 26s! [test_progs:2225] [ 48.503622] Modules linked in: bpf_testmod(O) [ 48.503622] CPU: 9 PID: 2225 Comm: test_progs Tainted: G O 6.9.0-08561-g2c1713a8f1c9-dirty #69 [ 48.507629] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 [ 48.511635] RIP: 0010:handle_softirqs+0x71/0x290 [ 48.511635] Code: [...] 10 0a 00 00 00 31 c0 65 66 89 05 d5 f4 fa 7e fb bb ff ff ff ff <49> c7 c2 cb [ 48.518527] RSP: 0018:ffffc90000310fa0 EFLAGS: 00000246 [ 48.519579] RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 00000000000006e0 [ 48.522526] RDX: 0000000000000006 RSI: ffff88810791ae80 RDI: 0000000000000000 [ 48.523587] RBP: ffffc90000fabc88 R08: 00000005a0af4f7f R09: 0000000000000000 [ 48.525525] R10: 0000000561d2f29c R11: 0000000000006534 R12: 0000000000000280 [ 48.528525] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 48.528525] FS: 00007f2f2885cd00(0000) GS:ffff888237c40000(0000) knlGS:0000000000000000 [ 48.531600] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 48.535520] CR2: 00007f2f287059f0 CR3: 0000000106a28002 CR4: 00000000003706f0 [ 48.537538] Call Trace: [ 48.537538] <IRQ> [ 48.537538] ? watchdog_timer_fn+0x1cd/0x250 [ 48.539590] ? lockup_detector_update_enable+0x50/0x50 [ 48.539590] ? __hrtimer_run_queues+0xff/0x280 [ 48.542520] ? hrtimer_interrupt+0x103/0x230 [ 48.544524] ? __sysvec_apic_timer_interrupt+0x4f/0x140 [ 48.545522] ? sysvec_apic_timer_interrupt+0x3a/0x90 [ 48.547612] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.547612] ? handle_softirqs+0x71/0x290 [ 48.547612] irq_exit_rcu+0x63/0x80 [ 48.551585] sysvec_apic_timer_interrupt+0x75/0x90 [ 48.552521] </IRQ> [ 48.553529] <TASK> [ 48.553529] asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.555609] RIP: 0010:finish_task_switch.isra.0+0x90/0x260 [ 48.556526] Code: [...] 9f 58 0a 00 00 48 85 db 0f 85 89 01 00 00 4c 89 ff e8 53 d9 bd 00 fb 66 90 <4d> 85 ed 74 [ 48.562524] RSP: 0018:ffffc90000fabd38 EFLAGS: 00000282 [ 48.563589] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83385620 [ 48.563589] RDX: ffff888237c73ae4 RSI: 0000000000000000 RDI: ffff888237c6fd00 [ 48.568521] RBP: ffffc90000fabd68 R08: 0000000000000000 R09: 0000000000000000 [ 48.569528] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8881009d0000 [ 48.573525] R13: ffff8881024e5400 R14: ffff88810791ae80 R15: ffff888237c6fd00 [ 48.575614] ? finish_task_switch.isra.0+0x8d/0x260 [ 48.576523] __schedule+0x364/0xac0 [ 48.577535] schedule+0x2e/0x110 [ 48.578555] pipe_read+0x301/0x400 [ 48.579589] ? destroy_sched_domains_rcu+0x30/0x30 [ 48.579589] vfs_read+0x2b3/0x2f0 [ 48.579589] ksys_read+0x8b/0xc0 [ 48.583590] do_syscall_64+0x3d/0xc0 [ 48.583590] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 48.586525] RIP: 0033:0x7f2f28703fa1 [ 48.587592] Code: [...] 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 80 3d c5 23 14 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 [ 48.593534] RSP: 002b:00007ffd90f8cf88 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 48.595589] RAX: ffffffffffffffda RBX: 00007ffd90f8d5e8 RCX: 00007f2f28703fa1 [ 48.595589] RDX: 0000000000000001 RSI: 00007ffd90f8cfb0 RDI: 0000000000000006 [ 48.599592] RBP: 00007ffd90f8d2f0 R08: 0000000000000064 R09: 0000000000000000 [ 48.602527] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 48.603589] R13: 00007ffd90f8d608 R14: 00007f2f288d8000 R15: 0000000000f6bdb0 [ 48.605527] </TASK> In the test, two processes are communicating through pipe. Further debugging with strace found that the above splat is triggered as read() syscall could not receive the data even if the corresponding write() syscall in another process successfully wrote data into the pipe. The failed subtest is "send_signal_perf". The corresponding perf event has sample_period 1 and config PERF_COUNT_SW_CPU_CLOCK. sample_period 1 means every overflow event will trigger a call to the BPF program. So I suspect this may overwhelm the system. So I increased the sample_period to 100,000 and the test passed. The sample_period 10,000 still has the test failed. In other parts of selftest, e.g., [1], sample_freq is used instead. So I decided to use sample_freq = 1,000 since the test can pass as well. [1] https://lore.kernel.org/bpf/20240604070700.3032142-1-song@kernel.org/ Reported-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Yonghong Song <yonghong.song(a)linux.dev> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> Link: https://lore.kernel.org/bpf/20240605201203.2603846-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/prog_tests/send_signal.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c index b607112c64e7a..281d097b4b76a 100644 --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c @@ -174,7 +174,8 @@ static void test_send_signal_tracepoint(void) static void test_send_signal_perf(void) { struct perf_event_attr attr = { - .sample_period = 1, + .freq = 1, + .sample_freq = 1000, .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_CLOCK, }; -- 2.43.0

8 months, 3 weeks

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[PATCH AUTOSEL 5.10 2/6] selftests/bpf: Fix send_signal test with nested CONFIG_PARAVIRT

by Sasha Levin

From: Yonghong Song <yonghong.song(a)linux.dev> [ Upstream commit 7015843afcaf68c132784c89528dfddc0005e483 ] Alexei reported that send_signal test may fail with nested CONFIG_PARAVIRT configs. In this particular case, the base VM is AMD with 166 cpus, and I run selftests with regular qemu on top of that and indeed send_signal test failed. I also tried with an Intel box with 80 cpus and there is no issue. The main qemu command line includes: -enable-kvm -smp 16 -cpu host The failure log looks like: $ ./test_progs -t send_signal [ 48.501588] watchdog: BUG: soft lockup - CPU#9 stuck for 26s! [test_progs:2225] [ 48.503622] Modules linked in: bpf_testmod(O) [ 48.503622] CPU: 9 PID: 2225 Comm: test_progs Tainted: G O 6.9.0-08561-g2c1713a8f1c9-dirty #69 [ 48.507629] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 [ 48.511635] RIP: 0010:handle_softirqs+0x71/0x290 [ 48.511635] Code: [...] 10 0a 00 00 00 31 c0 65 66 89 05 d5 f4 fa 7e fb bb ff ff ff ff <49> c7 c2 cb [ 48.518527] RSP: 0018:ffffc90000310fa0 EFLAGS: 00000246 [ 48.519579] RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 00000000000006e0 [ 48.522526] RDX: 0000000000000006 RSI: ffff88810791ae80 RDI: 0000000000000000 [ 48.523587] RBP: ffffc90000fabc88 R08: 00000005a0af4f7f R09: 0000000000000000 [ 48.525525] R10: 0000000561d2f29c R11: 0000000000006534 R12: 0000000000000280 [ 48.528525] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 48.528525] FS: 00007f2f2885cd00(0000) GS:ffff888237c40000(0000) knlGS:0000000000000000 [ 48.531600] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 48.535520] CR2: 00007f2f287059f0 CR3: 0000000106a28002 CR4: 00000000003706f0 [ 48.537538] Call Trace: [ 48.537538] <IRQ> [ 48.537538] ? watchdog_timer_fn+0x1cd/0x250 [ 48.539590] ? lockup_detector_update_enable+0x50/0x50 [ 48.539590] ? __hrtimer_run_queues+0xff/0x280 [ 48.542520] ? hrtimer_interrupt+0x103/0x230 [ 48.544524] ? __sysvec_apic_timer_interrupt+0x4f/0x140 [ 48.545522] ? sysvec_apic_timer_interrupt+0x3a/0x90 [ 48.547612] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.547612] ? handle_softirqs+0x71/0x290 [ 48.547612] irq_exit_rcu+0x63/0x80 [ 48.551585] sysvec_apic_timer_interrupt+0x75/0x90 [ 48.552521] </IRQ> [ 48.553529] <TASK> [ 48.553529] asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.555609] RIP: 0010:finish_task_switch.isra.0+0x90/0x260 [ 48.556526] Code: [...] 9f 58 0a 00 00 48 85 db 0f 85 89 01 00 00 4c 89 ff e8 53 d9 bd 00 fb 66 90 <4d> 85 ed 74 [ 48.562524] RSP: 0018:ffffc90000fabd38 EFLAGS: 00000282 [ 48.563589] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83385620 [ 48.563589] RDX: ffff888237c73ae4 RSI: 0000000000000000 RDI: ffff888237c6fd00 [ 48.568521] RBP: ffffc90000fabd68 R08: 0000000000000000 R09: 0000000000000000 [ 48.569528] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8881009d0000 [ 48.573525] R13: ffff8881024e5400 R14: ffff88810791ae80 R15: ffff888237c6fd00 [ 48.575614] ? finish_task_switch.isra.0+0x8d/0x260 [ 48.576523] __schedule+0x364/0xac0 [ 48.577535] schedule+0x2e/0x110 [ 48.578555] pipe_read+0x301/0x400 [ 48.579589] ? destroy_sched_domains_rcu+0x30/0x30 [ 48.579589] vfs_read+0x2b3/0x2f0 [ 48.579589] ksys_read+0x8b/0xc0 [ 48.583590] do_syscall_64+0x3d/0xc0 [ 48.583590] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 48.586525] RIP: 0033:0x7f2f28703fa1 [ 48.587592] Code: [...] 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 80 3d c5 23 14 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 [ 48.593534] RSP: 002b:00007ffd90f8cf88 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 48.595589] RAX: ffffffffffffffda RBX: 00007ffd90f8d5e8 RCX: 00007f2f28703fa1 [ 48.595589] RDX: 0000000000000001 RSI: 00007ffd90f8cfb0 RDI: 0000000000000006 [ 48.599592] RBP: 00007ffd90f8d2f0 R08: 0000000000000064 R09: 0000000000000000 [ 48.602527] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 48.603589] R13: 00007ffd90f8d608 R14: 00007f2f288d8000 R15: 0000000000f6bdb0 [ 48.605527] </TASK> In the test, two processes are communicating through pipe. Further debugging with strace found that the above splat is triggered as read() syscall could not receive the data even if the corresponding write() syscall in another process successfully wrote data into the pipe. The failed subtest is "send_signal_perf". The corresponding perf event has sample_period 1 and config PERF_COUNT_SW_CPU_CLOCK. sample_period 1 means every overflow event will trigger a call to the BPF program. So I suspect this may overwhelm the system. So I increased the sample_period to 100,000 and the test passed. The sample_period 10,000 still has the test failed. In other parts of selftest, e.g., [1], sample_freq is used instead. So I decided to use sample_freq = 1,000 since the test can pass as well. [1] https://lore.kernel.org/bpf/20240604070700.3032142-1-song@kernel.org/ Reported-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Yonghong Song <yonghong.song(a)linux.dev> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> Link: https://lore.kernel.org/bpf/20240605201203.2603846-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/prog_tests/send_signal.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c index 75b72c751772b..0b6349070824b 100644 --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c @@ -155,7 +155,8 @@ static void test_send_signal_tracepoint(bool signal_thread) static void test_send_signal_perf(bool signal_thread) { struct perf_event_attr attr = { - .sample_period = 1, + .freq = 1, + .sample_freq = 1000, .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_CLOCK, }; -- 2.43.0

8 months, 3 weeks

1
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[PATCH AUTOSEL 5.15 2/6] selftests/bpf: Fix send_signal test with nested CONFIG_PARAVIRT

by Sasha Levin

From: Yonghong Song <yonghong.song(a)linux.dev> [ Upstream commit 7015843afcaf68c132784c89528dfddc0005e483 ] Alexei reported that send_signal test may fail with nested CONFIG_PARAVIRT configs. In this particular case, the base VM is AMD with 166 cpus, and I run selftests with regular qemu on top of that and indeed send_signal test failed. I also tried with an Intel box with 80 cpus and there is no issue. The main qemu command line includes: -enable-kvm -smp 16 -cpu host The failure log looks like: $ ./test_progs -t send_signal [ 48.501588] watchdog: BUG: soft lockup - CPU#9 stuck for 26s! [test_progs:2225] [ 48.503622] Modules linked in: bpf_testmod(O) [ 48.503622] CPU: 9 PID: 2225 Comm: test_progs Tainted: G O 6.9.0-08561-g2c1713a8f1c9-dirty #69 [ 48.507629] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 [ 48.511635] RIP: 0010:handle_softirqs+0x71/0x290 [ 48.511635] Code: [...] 10 0a 00 00 00 31 c0 65 66 89 05 d5 f4 fa 7e fb bb ff ff ff ff <49> c7 c2 cb [ 48.518527] RSP: 0018:ffffc90000310fa0 EFLAGS: 00000246 [ 48.519579] RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 00000000000006e0 [ 48.522526] RDX: 0000000000000006 RSI: ffff88810791ae80 RDI: 0000000000000000 [ 48.523587] RBP: ffffc90000fabc88 R08: 00000005a0af4f7f R09: 0000000000000000 [ 48.525525] R10: 0000000561d2f29c R11: 0000000000006534 R12: 0000000000000280 [ 48.528525] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 48.528525] FS: 00007f2f2885cd00(0000) GS:ffff888237c40000(0000) knlGS:0000000000000000 [ 48.531600] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 48.535520] CR2: 00007f2f287059f0 CR3: 0000000106a28002 CR4: 00000000003706f0 [ 48.537538] Call Trace: [ 48.537538] <IRQ> [ 48.537538] ? watchdog_timer_fn+0x1cd/0x250 [ 48.539590] ? lockup_detector_update_enable+0x50/0x50 [ 48.539590] ? __hrtimer_run_queues+0xff/0x280 [ 48.542520] ? hrtimer_interrupt+0x103/0x230 [ 48.544524] ? __sysvec_apic_timer_interrupt+0x4f/0x140 [ 48.545522] ? sysvec_apic_timer_interrupt+0x3a/0x90 [ 48.547612] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.547612] ? handle_softirqs+0x71/0x290 [ 48.547612] irq_exit_rcu+0x63/0x80 [ 48.551585] sysvec_apic_timer_interrupt+0x75/0x90 [ 48.552521] </IRQ> [ 48.553529] <TASK> [ 48.553529] asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.555609] RIP: 0010:finish_task_switch.isra.0+0x90/0x260 [ 48.556526] Code: [...] 9f 58 0a 00 00 48 85 db 0f 85 89 01 00 00 4c 89 ff e8 53 d9 bd 00 fb 66 90 <4d> 85 ed 74 [ 48.562524] RSP: 0018:ffffc90000fabd38 EFLAGS: 00000282 [ 48.563589] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83385620 [ 48.563589] RDX: ffff888237c73ae4 RSI: 0000000000000000 RDI: ffff888237c6fd00 [ 48.568521] RBP: ffffc90000fabd68 R08: 0000000000000000 R09: 0000000000000000 [ 48.569528] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8881009d0000 [ 48.573525] R13: ffff8881024e5400 R14: ffff88810791ae80 R15: ffff888237c6fd00 [ 48.575614] ? finish_task_switch.isra.0+0x8d/0x260 [ 48.576523] __schedule+0x364/0xac0 [ 48.577535] schedule+0x2e/0x110 [ 48.578555] pipe_read+0x301/0x400 [ 48.579589] ? destroy_sched_domains_rcu+0x30/0x30 [ 48.579589] vfs_read+0x2b3/0x2f0 [ 48.579589] ksys_read+0x8b/0xc0 [ 48.583590] do_syscall_64+0x3d/0xc0 [ 48.583590] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 48.586525] RIP: 0033:0x7f2f28703fa1 [ 48.587592] Code: [...] 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 80 3d c5 23 14 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 [ 48.593534] RSP: 002b:00007ffd90f8cf88 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 48.595589] RAX: ffffffffffffffda RBX: 00007ffd90f8d5e8 RCX: 00007f2f28703fa1 [ 48.595589] RDX: 0000000000000001 RSI: 00007ffd90f8cfb0 RDI: 0000000000000006 [ 48.599592] RBP: 00007ffd90f8d2f0 R08: 0000000000000064 R09: 0000000000000000 [ 48.602527] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 48.603589] R13: 00007ffd90f8d608 R14: 00007f2f288d8000 R15: 0000000000f6bdb0 [ 48.605527] </TASK> In the test, two processes are communicating through pipe. Further debugging with strace found that the above splat is triggered as read() syscall could not receive the data even if the corresponding write() syscall in another process successfully wrote data into the pipe. The failed subtest is "send_signal_perf". The corresponding perf event has sample_period 1 and config PERF_COUNT_SW_CPU_CLOCK. sample_period 1 means every overflow event will trigger a call to the BPF program. So I suspect this may overwhelm the system. So I increased the sample_period to 100,000 and the test passed. The sample_period 10,000 still has the test failed. In other parts of selftest, e.g., [1], sample_freq is used instead. So I decided to use sample_freq = 1,000 since the test can pass as well. [1] https://lore.kernel.org/bpf/20240604070700.3032142-1-song@kernel.org/ Reported-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Yonghong Song <yonghong.song(a)linux.dev> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> Link: https://lore.kernel.org/bpf/20240605201203.2603846-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/prog_tests/send_signal.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c index 776916b61c406..7b1343f70e65a 100644 --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c @@ -149,7 +149,8 @@ static void test_send_signal_tracepoint(bool signal_thread) static void test_send_signal_perf(bool signal_thread) { struct perf_event_attr attr = { - .sample_period = 1, + .freq = 1, + .sample_freq = 1000, .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_CLOCK, }; -- 2.43.0

8 months, 3 weeks

1
0
0 0

[PATCH AUTOSEL 6.1 04/11] selftests/bpf: Fix send_signal test with nested CONFIG_PARAVIRT

by Sasha Levin

From: Yonghong Song <yonghong.song(a)linux.dev> [ Upstream commit 7015843afcaf68c132784c89528dfddc0005e483 ] Alexei reported that send_signal test may fail with nested CONFIG_PARAVIRT configs. In this particular case, the base VM is AMD with 166 cpus, and I run selftests with regular qemu on top of that and indeed send_signal test failed. I also tried with an Intel box with 80 cpus and there is no issue. The main qemu command line includes: -enable-kvm -smp 16 -cpu host The failure log looks like: $ ./test_progs -t send_signal [ 48.501588] watchdog: BUG: soft lockup - CPU#9 stuck for 26s! [test_progs:2225] [ 48.503622] Modules linked in: bpf_testmod(O) [ 48.503622] CPU: 9 PID: 2225 Comm: test_progs Tainted: G O 6.9.0-08561-g2c1713a8f1c9-dirty #69 [ 48.507629] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 [ 48.511635] RIP: 0010:handle_softirqs+0x71/0x290 [ 48.511635] Code: [...] 10 0a 00 00 00 31 c0 65 66 89 05 d5 f4 fa 7e fb bb ff ff ff ff <49> c7 c2 cb [ 48.518527] RSP: 0018:ffffc90000310fa0 EFLAGS: 00000246 [ 48.519579] RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 00000000000006e0 [ 48.522526] RDX: 0000000000000006 RSI: ffff88810791ae80 RDI: 0000000000000000 [ 48.523587] RBP: ffffc90000fabc88 R08: 00000005a0af4f7f R09: 0000000000000000 [ 48.525525] R10: 0000000561d2f29c R11: 0000000000006534 R12: 0000000000000280 [ 48.528525] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 48.528525] FS: 00007f2f2885cd00(0000) GS:ffff888237c40000(0000) knlGS:0000000000000000 [ 48.531600] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 48.535520] CR2: 00007f2f287059f0 CR3: 0000000106a28002 CR4: 00000000003706f0 [ 48.537538] Call Trace: [ 48.537538] <IRQ> [ 48.537538] ? watchdog_timer_fn+0x1cd/0x250 [ 48.539590] ? lockup_detector_update_enable+0x50/0x50 [ 48.539590] ? __hrtimer_run_queues+0xff/0x280 [ 48.542520] ? hrtimer_interrupt+0x103/0x230 [ 48.544524] ? __sysvec_apic_timer_interrupt+0x4f/0x140 [ 48.545522] ? sysvec_apic_timer_interrupt+0x3a/0x90 [ 48.547612] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.547612] ? handle_softirqs+0x71/0x290 [ 48.547612] irq_exit_rcu+0x63/0x80 [ 48.551585] sysvec_apic_timer_interrupt+0x75/0x90 [ 48.552521] </IRQ> [ 48.553529] <TASK> [ 48.553529] asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.555609] RIP: 0010:finish_task_switch.isra.0+0x90/0x260 [ 48.556526] Code: [...] 9f 58 0a 00 00 48 85 db 0f 85 89 01 00 00 4c 89 ff e8 53 d9 bd 00 fb 66 90 <4d> 85 ed 74 [ 48.562524] RSP: 0018:ffffc90000fabd38 EFLAGS: 00000282 [ 48.563589] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83385620 [ 48.563589] RDX: ffff888237c73ae4 RSI: 0000000000000000 RDI: ffff888237c6fd00 [ 48.568521] RBP: ffffc90000fabd68 R08: 0000000000000000 R09: 0000000000000000 [ 48.569528] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8881009d0000 [ 48.573525] R13: ffff8881024e5400 R14: ffff88810791ae80 R15: ffff888237c6fd00 [ 48.575614] ? finish_task_switch.isra.0+0x8d/0x260 [ 48.576523] __schedule+0x364/0xac0 [ 48.577535] schedule+0x2e/0x110 [ 48.578555] pipe_read+0x301/0x400 [ 48.579589] ? destroy_sched_domains_rcu+0x30/0x30 [ 48.579589] vfs_read+0x2b3/0x2f0 [ 48.579589] ksys_read+0x8b/0xc0 [ 48.583590] do_syscall_64+0x3d/0xc0 [ 48.583590] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 48.586525] RIP: 0033:0x7f2f28703fa1 [ 48.587592] Code: [...] 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 80 3d c5 23 14 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 [ 48.593534] RSP: 002b:00007ffd90f8cf88 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 48.595589] RAX: ffffffffffffffda RBX: 00007ffd90f8d5e8 RCX: 00007f2f28703fa1 [ 48.595589] RDX: 0000000000000001 RSI: 00007ffd90f8cfb0 RDI: 0000000000000006 [ 48.599592] RBP: 00007ffd90f8d2f0 R08: 0000000000000064 R09: 0000000000000000 [ 48.602527] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 48.603589] R13: 00007ffd90f8d608 R14: 00007f2f288d8000 R15: 0000000000f6bdb0 [ 48.605527] </TASK> In the test, two processes are communicating through pipe. Further debugging with strace found that the above splat is triggered as read() syscall could not receive the data even if the corresponding write() syscall in another process successfully wrote data into the pipe. The failed subtest is "send_signal_perf". The corresponding perf event has sample_period 1 and config PERF_COUNT_SW_CPU_CLOCK. sample_period 1 means every overflow event will trigger a call to the BPF program. So I suspect this may overwhelm the system. So I increased the sample_period to 100,000 and the test passed. The sample_period 10,000 still has the test failed. In other parts of selftest, e.g., [1], sample_freq is used instead. So I decided to use sample_freq = 1,000 since the test can pass as well. [1] https://lore.kernel.org/bpf/20240604070700.3032142-1-song@kernel.org/ Reported-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Yonghong Song <yonghong.song(a)linux.dev> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> Link: https://lore.kernel.org/bpf/20240605201203.2603846-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/prog_tests/send_signal.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c index d63a20fbed339..210b806351bcf 100644 --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c @@ -152,7 +152,8 @@ static void test_send_signal_tracepoint(bool signal_thread) static void test_send_signal_perf(bool signal_thread) { struct perf_event_attr attr = { - .sample_period = 1, + .freq = 1, + .sample_freq = 1000, .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_CLOCK, }; -- 2.43.0

8 months, 3 weeks

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[PATCH AUTOSEL 6.6 05/15] selftests/bpf: Fix send_signal test with nested CONFIG_PARAVIRT

by Sasha Levin

From: Yonghong Song <yonghong.song(a)linux.dev> [ Upstream commit 7015843afcaf68c132784c89528dfddc0005e483 ] Alexei reported that send_signal test may fail with nested CONFIG_PARAVIRT configs. In this particular case, the base VM is AMD with 166 cpus, and I run selftests with regular qemu on top of that and indeed send_signal test failed. I also tried with an Intel box with 80 cpus and there is no issue. The main qemu command line includes: -enable-kvm -smp 16 -cpu host The failure log looks like: $ ./test_progs -t send_signal [ 48.501588] watchdog: BUG: soft lockup - CPU#9 stuck for 26s! [test_progs:2225] [ 48.503622] Modules linked in: bpf_testmod(O) [ 48.503622] CPU: 9 PID: 2225 Comm: test_progs Tainted: G O 6.9.0-08561-g2c1713a8f1c9-dirty #69 [ 48.507629] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 [ 48.511635] RIP: 0010:handle_softirqs+0x71/0x290 [ 48.511635] Code: [...] 10 0a 00 00 00 31 c0 65 66 89 05 d5 f4 fa 7e fb bb ff ff ff ff <49> c7 c2 cb [ 48.518527] RSP: 0018:ffffc90000310fa0 EFLAGS: 00000246 [ 48.519579] RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 00000000000006e0 [ 48.522526] RDX: 0000000000000006 RSI: ffff88810791ae80 RDI: 0000000000000000 [ 48.523587] RBP: ffffc90000fabc88 R08: 00000005a0af4f7f R09: 0000000000000000 [ 48.525525] R10: 0000000561d2f29c R11: 0000000000006534 R12: 0000000000000280 [ 48.528525] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 48.528525] FS: 00007f2f2885cd00(0000) GS:ffff888237c40000(0000) knlGS:0000000000000000 [ 48.531600] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 48.535520] CR2: 00007f2f287059f0 CR3: 0000000106a28002 CR4: 00000000003706f0 [ 48.537538] Call Trace: [ 48.537538] <IRQ> [ 48.537538] ? watchdog_timer_fn+0x1cd/0x250 [ 48.539590] ? lockup_detector_update_enable+0x50/0x50 [ 48.539590] ? __hrtimer_run_queues+0xff/0x280 [ 48.542520] ? hrtimer_interrupt+0x103/0x230 [ 48.544524] ? __sysvec_apic_timer_interrupt+0x4f/0x140 [ 48.545522] ? sysvec_apic_timer_interrupt+0x3a/0x90 [ 48.547612] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.547612] ? handle_softirqs+0x71/0x290 [ 48.547612] irq_exit_rcu+0x63/0x80 [ 48.551585] sysvec_apic_timer_interrupt+0x75/0x90 [ 48.552521] </IRQ> [ 48.553529] <TASK> [ 48.553529] asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.555609] RIP: 0010:finish_task_switch.isra.0+0x90/0x260 [ 48.556526] Code: [...] 9f 58 0a 00 00 48 85 db 0f 85 89 01 00 00 4c 89 ff e8 53 d9 bd 00 fb 66 90 <4d> 85 ed 74 [ 48.562524] RSP: 0018:ffffc90000fabd38 EFLAGS: 00000282 [ 48.563589] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83385620 [ 48.563589] RDX: ffff888237c73ae4 RSI: 0000000000000000 RDI: ffff888237c6fd00 [ 48.568521] RBP: ffffc90000fabd68 R08: 0000000000000000 R09: 0000000000000000 [ 48.569528] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8881009d0000 [ 48.573525] R13: ffff8881024e5400 R14: ffff88810791ae80 R15: ffff888237c6fd00 [ 48.575614] ? finish_task_switch.isra.0+0x8d/0x260 [ 48.576523] __schedule+0x364/0xac0 [ 48.577535] schedule+0x2e/0x110 [ 48.578555] pipe_read+0x301/0x400 [ 48.579589] ? destroy_sched_domains_rcu+0x30/0x30 [ 48.579589] vfs_read+0x2b3/0x2f0 [ 48.579589] ksys_read+0x8b/0xc0 [ 48.583590] do_syscall_64+0x3d/0xc0 [ 48.583590] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 48.586525] RIP: 0033:0x7f2f28703fa1 [ 48.587592] Code: [...] 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 80 3d c5 23 14 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 [ 48.593534] RSP: 002b:00007ffd90f8cf88 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 48.595589] RAX: ffffffffffffffda RBX: 00007ffd90f8d5e8 RCX: 00007f2f28703fa1 [ 48.595589] RDX: 0000000000000001 RSI: 00007ffd90f8cfb0 RDI: 0000000000000006 [ 48.599592] RBP: 00007ffd90f8d2f0 R08: 0000000000000064 R09: 0000000000000000 [ 48.602527] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 48.603589] R13: 00007ffd90f8d608 R14: 00007f2f288d8000 R15: 0000000000f6bdb0 [ 48.605527] </TASK> In the test, two processes are communicating through pipe. Further debugging with strace found that the above splat is triggered as read() syscall could not receive the data even if the corresponding write() syscall in another process successfully wrote data into the pipe. The failed subtest is "send_signal_perf". The corresponding perf event has sample_period 1 and config PERF_COUNT_SW_CPU_CLOCK. sample_period 1 means every overflow event will trigger a call to the BPF program. So I suspect this may overwhelm the system. So I increased the sample_period to 100,000 and the test passed. The sample_period 10,000 still has the test failed. In other parts of selftest, e.g., [1], sample_freq is used instead. So I decided to use sample_freq = 1,000 since the test can pass as well. [1] https://lore.kernel.org/bpf/20240604070700.3032142-1-song@kernel.org/ Reported-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Yonghong Song <yonghong.song(a)linux.dev> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> Link: https://lore.kernel.org/bpf/20240605201203.2603846-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/prog_tests/send_signal.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c index b15b343ebb6b1..9adcda7f1fedc 100644 --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c @@ -156,7 +156,8 @@ static void test_send_signal_tracepoint(bool signal_thread) static void test_send_signal_perf(bool signal_thread) { struct perf_event_attr attr = { - .sample_period = 1, + .freq = 1, + .sample_freq = 1000, .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_CLOCK, }; -- 2.43.0

8 months, 3 weeks

1
0
0 0

[PATCH AUTOSEL 6.10 07/27] selftests/bpf: Fix send_signal test with nested CONFIG_PARAVIRT

by Sasha Levin

From: Yonghong Song <yonghong.song(a)linux.dev> [ Upstream commit 7015843afcaf68c132784c89528dfddc0005e483 ] Alexei reported that send_signal test may fail with nested CONFIG_PARAVIRT configs. In this particular case, the base VM is AMD with 166 cpus, and I run selftests with regular qemu on top of that and indeed send_signal test failed. I also tried with an Intel box with 80 cpus and there is no issue. The main qemu command line includes: -enable-kvm -smp 16 -cpu host The failure log looks like: $ ./test_progs -t send_signal [ 48.501588] watchdog: BUG: soft lockup - CPU#9 stuck for 26s! [test_progs:2225] [ 48.503622] Modules linked in: bpf_testmod(O) [ 48.503622] CPU: 9 PID: 2225 Comm: test_progs Tainted: G O 6.9.0-08561-g2c1713a8f1c9-dirty #69 [ 48.507629] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 [ 48.511635] RIP: 0010:handle_softirqs+0x71/0x290 [ 48.511635] Code: [...] 10 0a 00 00 00 31 c0 65 66 89 05 d5 f4 fa 7e fb bb ff ff ff ff <49> c7 c2 cb [ 48.518527] RSP: 0018:ffffc90000310fa0 EFLAGS: 00000246 [ 48.519579] RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 00000000000006e0 [ 48.522526] RDX: 0000000000000006 RSI: ffff88810791ae80 RDI: 0000000000000000 [ 48.523587] RBP: ffffc90000fabc88 R08: 00000005a0af4f7f R09: 0000000000000000 [ 48.525525] R10: 0000000561d2f29c R11: 0000000000006534 R12: 0000000000000280 [ 48.528525] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 48.528525] FS: 00007f2f2885cd00(0000) GS:ffff888237c40000(0000) knlGS:0000000000000000 [ 48.531600] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 48.535520] CR2: 00007f2f287059f0 CR3: 0000000106a28002 CR4: 00000000003706f0 [ 48.537538] Call Trace: [ 48.537538] <IRQ> [ 48.537538] ? watchdog_timer_fn+0x1cd/0x250 [ 48.539590] ? lockup_detector_update_enable+0x50/0x50 [ 48.539590] ? __hrtimer_run_queues+0xff/0x280 [ 48.542520] ? hrtimer_interrupt+0x103/0x230 [ 48.544524] ? __sysvec_apic_timer_interrupt+0x4f/0x140 [ 48.545522] ? sysvec_apic_timer_interrupt+0x3a/0x90 [ 48.547612] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.547612] ? handle_softirqs+0x71/0x290 [ 48.547612] irq_exit_rcu+0x63/0x80 [ 48.551585] sysvec_apic_timer_interrupt+0x75/0x90 [ 48.552521] </IRQ> [ 48.553529] <TASK> [ 48.553529] asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 48.555609] RIP: 0010:finish_task_switch.isra.0+0x90/0x260 [ 48.556526] Code: [...] 9f 58 0a 00 00 48 85 db 0f 85 89 01 00 00 4c 89 ff e8 53 d9 bd 00 fb 66 90 <4d> 85 ed 74 [ 48.562524] RSP: 0018:ffffc90000fabd38 EFLAGS: 00000282 [ 48.563589] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83385620 [ 48.563589] RDX: ffff888237c73ae4 RSI: 0000000000000000 RDI: ffff888237c6fd00 [ 48.568521] RBP: ffffc90000fabd68 R08: 0000000000000000 R09: 0000000000000000 [ 48.569528] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8881009d0000 [ 48.573525] R13: ffff8881024e5400 R14: ffff88810791ae80 R15: ffff888237c6fd00 [ 48.575614] ? finish_task_switch.isra.0+0x8d/0x260 [ 48.576523] __schedule+0x364/0xac0 [ 48.577535] schedule+0x2e/0x110 [ 48.578555] pipe_read+0x301/0x400 [ 48.579589] ? destroy_sched_domains_rcu+0x30/0x30 [ 48.579589] vfs_read+0x2b3/0x2f0 [ 48.579589] ksys_read+0x8b/0xc0 [ 48.583590] do_syscall_64+0x3d/0xc0 [ 48.583590] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 48.586525] RIP: 0033:0x7f2f28703fa1 [ 48.587592] Code: [...] 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 80 3d c5 23 14 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 [ 48.593534] RSP: 002b:00007ffd90f8cf88 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 48.595589] RAX: ffffffffffffffda RBX: 00007ffd90f8d5e8 RCX: 00007f2f28703fa1 [ 48.595589] RDX: 0000000000000001 RSI: 00007ffd90f8cfb0 RDI: 0000000000000006 [ 48.599592] RBP: 00007ffd90f8d2f0 R08: 0000000000000064 R09: 0000000000000000 [ 48.602527] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 48.603589] R13: 00007ffd90f8d608 R14: 00007f2f288d8000 R15: 0000000000f6bdb0 [ 48.605527] </TASK> In the test, two processes are communicating through pipe. Further debugging with strace found that the above splat is triggered as read() syscall could not receive the data even if the corresponding write() syscall in another process successfully wrote data into the pipe. The failed subtest is "send_signal_perf". The corresponding perf event has sample_period 1 and config PERF_COUNT_SW_CPU_CLOCK. sample_period 1 means every overflow event will trigger a call to the BPF program. So I suspect this may overwhelm the system. So I increased the sample_period to 100,000 and the test passed. The sample_period 10,000 still has the test failed. In other parts of selftest, e.g., [1], sample_freq is used instead. So I decided to use sample_freq = 1,000 since the test can pass as well. [1] https://lore.kernel.org/bpf/20240604070700.3032142-1-song@kernel.org/ Reported-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Yonghong Song <yonghong.song(a)linux.dev> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> Link: https://lore.kernel.org/bpf/20240605201203.2603846-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/prog_tests/send_signal.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c index 920aee41bd58c..6cc69900b3106 100644 --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c @@ -156,7 +156,8 @@ static void test_send_signal_tracepoint(bool signal_thread) static void test_send_signal_perf(bool signal_thread) { struct perf_event_attr attr = { - .sample_period = 1, + .freq = 1, + .sample_freq = 1000, .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_CLOCK, }; -- 2.43.0

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