@@ -431,7 +431,7 @@ static int __find_race(void *arg)
signal:
seqno = get_random_u32_below(data->fc.chain_length - 1);
dma_fence_signal(data->fc.fences[seqno]);
- cond_resched();
+ fsleep(10000);
}
if (atomic_dec_and_test(&data->children))
@@ -505,6 +505,7 @@ static int signal_forward(void *arg)
for (i = 0; i < fc.chain_length; i++) {
dma_fence_signal(fc.fences[i]);
+ fsleep(10000);
if (!dma_fence_is_signaled(fc.chains[i])) {
pr_err("chain[%d] not signaled!\n", i);
@@ -537,6 +538,7 @@ static int signal_backward(void *arg)
for (i = fc.chain_length; i--; ) {
dma_fence_signal(fc.fences[i]);
+ fsleep(10000);
if (i > 0 && dma_fence_is_signaled(fc.chains[i])) {
pr_err("chain[%d] is signaled!\n", i);
@@ -587,8 +589,10 @@ static int wait_forward(void *arg)
get_task_struct(tsk);
yield_to(tsk, true);
- for (i = 0; i < fc.chain_length; i++)
+ for (i = 0; i < fc.chain_length; i++) {
dma_fence_signal(fc.fences[i]);
+ fsleep(10000);
+ }
err = kthread_stop_put(tsk);
@@ -616,8 +620,10 @@ static int wait_backward(void *arg)
get_task_struct(tsk);
yield_to(tsk, true);
- for (i = fc.chain_length; i--; )
+ for (i = fc.chain_length; i--; ) {
dma_fence_signal(fc.fences[i]);
+ fsleep(10000);
+ }
err = kthread_stop_put(tsk);
@@ -663,8 +669,10 @@ static int wait_random(void *arg)
get_task_struct(tsk);
yield_to(tsk, true);
- for (i = 0; i < fc.chain_length; i++)
+ for (i = 0; i < fc.chain_length; i++) {
dma_fence_signal(fc.fences[i]);
+ fsleep(10000);
+ }
err = kthread_stop_put(tsk);
Give the scheduler a chance to breath by adding delay of 10ms as some of the loops may take some time on old machines (like apl/bsw/pnv), and so catch the attention of the watchdogs. v1: Instead of cond_resched(), use more generic call like fsleep(). <Christian> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/12904 Signed-off-by: Nitin Gote <nitin.r.gote@intel.com> --- Hi, For reviewer reference, adding here watchdog issue seen on old machines during dma-fence-chain subtests testing. This log is retrieved from device pstore log while testing dam-buf@all-tests: dma-buf: Running dma_fence_chain Panic#1 Part7 <6> sizeof(dma_fence_chain)=184 <6> dma-buf: Running dma_fence_chain/sanitycheck <6> dma-buf: Running dma_fence_chain/find_seqno <6> dma-buf: Running dma_fence_chain/find_signaled <6> dma-buf: Running dma_fence_chain/find_out_of_order <6> dma-buf: Running dma_fence_chain/find_gap <6> dma-buf: Running dma_fence_chain/find_race <6> Completed 4095 cycles <6> dma-buf: Running dma_fence_chain/signal_forward <6> dma-buf: Running dma_fence_chain/signal_backward <6> dma-buf: Running dma_fence_chain/wait_forward <6> dma-buf: Running dma_fence_chain/wait_backward <0> watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [dmabuf:2263] Panic#1 Part6 <4> irq event stamp: 415735 <4> hardirqs last enabled at (415734): [<ffffffff813d3a1b>] handle_softirqs+0xab/0x4d0 <4> hardirqs last disabled at (415735): [<ffffffff827c7e31>] sysvec_apic_timer_interrupt+0x11/0xc0 <4> softirqs last enabled at (415728): [<ffffffff813d3f8f>] __irq_exit_rcu+0x13f/0x160 <4> softirqs last disabled at (415733): [<ffffffff813d3f8f>] __irq_exit_rcu+0x13f/0x160 <4> CPU: 2 UID: 0 PID: 2263 Comm: dmabuf Not tainted 6.14.0-rc2-drm-next_483-g7b91683e7de7+ #1 <4> Hardware name: Intel corporation NUC6CAYS/NUC6CAYB, BIOS AYAPLCEL.86A.0056.2018.0926.1100 09/26/2018 <4> RIP: 0010:handle_softirqs+0xb1/0x4d0 <4> RSP: 0018:ffffc90000154f60 EFLAGS: 00000246 <4> RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000 <4> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 <4> RBP: ffffc90000154fb8 R08: 0000000000000000 R09: 0000000000000000 <4> R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000000a <4> R13: 0000000000000200 R14: 0000000000000200 R15: 0000000000400100 <4> FS: 000077521c5cd940(0000) GS:ffff888277900000(0000) knlGS:0000000000000000 Panic#1 Part5 <4> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4> CR2: 00005dbfee8c00c4 CR3: 0000000133d38000 CR4: 00000000003526f0 <4> Call Trace: <4> <IRQ> <4> ? show_regs+0x6c/0x80 <4> ? watchdog_timer_fn+0x247/0x2d0 <4> ? __pfx_watchdog_timer_fn+0x10/0x10 <4> ? __hrtimer_run_queues+0x1d0/0x420 <4> ? hrtimer_interrupt+0x116/0x290 <4> ? __sysvec_apic_timer_interrupt+0x70/0x1e0 <4> ? sysvec_apic_timer_interrupt+0x47/0xc0 <4> ? asm_sysvec_apic_timer_interrupt+0x1b/0x20 <4> ? handle_softirqs+0xb1/0x4d0 <4> __irq_exit_rcu+0x13f/0x160 <4> irq_exit_rcu+0xe/0x20 <4> sysvec_irq_work+0xa0/0xc0 <4> </IRQ> <4> <TASK> <4> asm_sysvec_irq_work+0x1b/0x20 <4> RIP: 0010:_raw_spin_unlock_irqrestore+0x57/0x80 <4> RSP: 0018:ffffc9000292b8f0 EFLAGS: 00000246 <4> RAX: 0000000000000000 RBX: ffff88810f235480 RCX: 0000000000000000 <4> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 <4> RBP: ffffc9000292b900 R08: 0000000000000000 R09: 0000000000000000 <4> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000246 <4> R13: 0000000000000000 R14: 0000000000000246 R15: 000000000003828c Panic#1 Part4 <4> dma_fence_signal+0x49/0xb0 <4> wait_backward+0xf8/0x140 [dmabuf_selftests] <4> __subtests+0x75/0x1f0 [dmabuf_selftests] <4> dma_fence_chain+0x94/0xe0 [dmabuf_selftests] <4> st_init+0x6a/0xff0 [dmabuf_selftests] <4> ? __pfx_st_init+0x10/0x10 [dmabuf_selftests] <4> do_one_initcall+0x79/0x400 <4> do_init_module+0x97/0x2a0 <4> load_module+0x2c23/0x2f60 <4> init_module_from_file+0x97/0xe0 <4> ? init_module_from_file+0x97/0xe0 <4> idempotent_init_module+0x134/0x350 <4> __x64_sys_finit_module+0x77/0x100 <4> x64_sys_call+0x1f37/0x2650 <4> do_syscall_64+0x91/0x180 <4> ? trace_hardirqs_off+0x5d/0xe0 <4> ? syscall_exit_to_user_mode+0x95/0x260 <4> ? do_syscall_64+0x9d/0x180 <4> ? do_syscall_64+0x9d/0x180 <4> ? irqentry_exit+0x77/0xb0 <4> ? sysvec_apic_timer_interrupt+0x57/0xc0 <4> entry_SYSCALL_64_after_hwframe+0x76/0x7e <4> RIP: 0033:0x77521e72725d Signed-off-by: Nitin Gote <nitin.r.gote@intel.com> --- drivers/dma-buf/st-dma-fence-chain.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)