6.5-stable review patch. If anyone has any objections, please let me know.
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From: Douglas Anderson dianders@chromium.org
[ Upstream commit 1f38c86bb29f4548b8df01b47a313518e6ed2dfe ]
After commit 77c12fc95980 ("watchdog/hardlockup: add a "cpu" param to watchdog_hardlockup_check()") we started storing a `struct cpumask` on the stack in watchdog_hardlockup_check(). On systems with CONFIG_NR_CPUS set to 8192 this takes up 1K on the stack. That triggers warnings with `CONFIG_FRAME_WARN` set to 1024.
We'll use the new trigger_allbutcpu_cpu_backtrace() to avoid needing to use a CPU mask at all.
Link: https://lkml.kernel.org/r/20230804065935.v4.2.I501ab68cb926ee33a7c87e063d207... Fixes: 77c12fc95980 ("watchdog/hardlockup: add a "cpu" param to watchdog_hardlockup_check()") Signed-off-by: Douglas Anderson dianders@chromium.org Reported-by: kernel test robot lkp@intel.com Closes: https://lore.kernel.org/r/202307310955.pLZDhpnl-lkp@intel.com Acked-by: Michal Hocko mhocko@suse.com Reviewed-by: Petr Mladek pmladek@suse.com Cc: Lecopzer Chen lecopzer.chen@mediatek.com Cc: Pingfan Liu kernelfans@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/watchdog.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 085d7a78f62f0..d145305d95fe8 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -151,9 +151,6 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs) */ if (is_hardlockup(cpu)) { unsigned int this_cpu = smp_processor_id(); - struct cpumask backtrace_mask; - - cpumask_copy(&backtrace_mask, cpu_online_mask);
/* Only print hardlockups once. */ if (per_cpu(watchdog_hardlockup_warned, cpu)) @@ -167,10 +164,8 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs) show_regs(regs); else dump_stack(); - cpumask_clear_cpu(cpu, &backtrace_mask); } else { - if (trigger_single_cpu_backtrace(cpu)) - cpumask_clear_cpu(cpu, &backtrace_mask); + trigger_single_cpu_backtrace(cpu); }
/* @@ -179,7 +174,7 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs) */ if (sysctl_hardlockup_all_cpu_backtrace && !test_and_set_bit(0, &watchdog_hardlockup_all_cpu_dumped)) - trigger_cpumask_backtrace(&backtrace_mask); + trigger_allbutcpu_cpu_backtrace(cpu);
if (hardlockup_panic) nmi_panic(regs, "Hard LOCKUP");