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| author | Cliff Wickman <cpw@sgi.com> | 2010-07-20 18:09:05 -0500 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2010-07-21 11:33:27 -0700 |
| commit | 5edd19af18a36a4e22c570b1b969179e0ca1fe4c (patch) | |
| tree | ad4c52f24218c1358d8e8ea51d2ce23a20c37d68 /arch/x86/kernel/apic | |
| parent | 93a7ca0c3ebe5d931126f1fb732cb9c4518383d4 (diff) | |
| download | op-kernel-dev-5edd19af18a36a4e22c570b1b969179e0ca1fe4c.zip op-kernel-dev-5edd19af18a36a4e22c570b1b969179e0ca1fe4c.tar.gz | |
x86, UV: Make kdump avoid stack dumps
UV NMI callback's should not write stack dumps when a kdump is to be written.
When invoking the crash kernel to write a dump, kdump_nmi_shootdown_cpus()
uses NMI's to get all the cpu's to save their register context and halt.
But the NMI interrupt handler runs a callback list. This patch sets a flag
to prevent any of those callbacks from interfering with the halt of the cpu.
For UV, which currently has the only callback to which this is relevant, the
uv_handle_nmi() callback should not do dumping of stacks.
The 'in_crash_kexec' flag is defined as an extern in kdebug.h firstly
because x2apic_uv_x.c includes it. Secondly because some future callback
might need the flag to know that it should not enter the debugger.
(Such a scenario was in fact present in the 2.6.32 kernel, SuSE distribution,
where a call to kdb needed to be avoided.)
Signed-off-by: Cliff Wickman <cpw@sgi.com>
LKML-Reference: <E1ObLvt-0005UZ-Va@eag09.americas.sgi.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/kernel/apic')
| -rw-r--r-- | arch/x86/kernel/apic/x2apic_uv_x.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c index e46f98f..7b598b8 100644 --- a/arch/x86/kernel/apic/x2apic_uv_x.c +++ b/arch/x86/kernel/apic/x2apic_uv_x.c @@ -604,6 +604,10 @@ int uv_handle_nmi(struct notifier_block *self, unsigned long reason, void *data) { if (reason != DIE_NMI_IPI) return NOTIFY_OK; + + if (in_crash_kexec) + /* do nothing if entering the crash kernel */ + return NOTIFY_OK; /* * Use a lock so only one cpu prints at a time * to prevent intermixed output. |
