diff options
| author | David Woodhouse <dwmw@amazon.co.uk> | 2024-09-26 16:17:37 +0100 |
|---|---|---|
| committer | Boqun Feng <boqun.feng@gmail.com> | 2024-10-17 20:07:22 -0700 |
| commit | 0784181b44af831a3fa52e1e5ff77c388d699dba (patch) | |
| tree | d677e86aacf6b04fc9082e6d33f6686d89a81c94 /kernel/cpu.c | |
| parent | 87347f148061b48c3495fb61dcbad384760da9cf (diff) | |
lockdep: Add lockdep_cleanup_dead_cpu()
Add a function to check that an offline CPU has left the tracing
infrastructure in a sane state.
Commit 9bb69ba4c177 ("ACPI: processor_idle: use raw_safe_halt() in
acpi_idle_play_dead()") fixed an issue where the acpi_idle_play_dead()
function called safe_halt() instead of raw_safe_halt(), which had the
side-effect of setting the hardirqs_enabled flag for the offline CPU.
On x86 this triggered warnings from lockdep_assert_irqs_disabled() when
the CPU was brought back online again later. These warnings were too
early for the exception to be handled correctly, leading to a
triple-fault.
Add lockdep_cleanup_dead_cpu() to check for this kind of failure mode,
print the events leading up to it, and correct it so that the CPU can
come online again correctly. Re-introducing the original bug now merely
results in this warning instead:
[ 61.556652] smpboot: CPU 1 is now offline
[ 61.556769] CPU 1 left hardirqs enabled!
[ 61.556915] irq event stamp: 128149
[ 61.556965] hardirqs last enabled at (128149): [<ffffffff81720a36>] acpi_idle_play_dead+0x46/0x70
[ 61.557055] hardirqs last disabled at (128148): [<ffffffff81124d50>] do_idle+0x90/0xe0
[ 61.557117] softirqs last enabled at (128078): [<ffffffff81cec74c>] __do_softirq+0x31c/0x423
[ 61.557199] softirqs last disabled at (128065): [<ffffffff810baae1>] __irq_exit_rcu+0x91/0x100
[boqun: Capitalize the title and reword the message a bit]
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/f7bd2b3b999051bb3ef4be34526a9262008285f5.camel@infradead.org
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index d293d52a3e00..c4aaf73dec9e 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1338,6 +1338,7 @@ static int takedown_cpu(unsigned int cpu) cpuhp_bp_sync_dead(cpu); + lockdep_cleanup_dead_cpu(cpu, idle_thread_get(cpu)); tick_cleanup_dead_cpu(cpu); /* |