From: Tianyu Lan Tianyu.Lan@microsoft.com
commit f3a99e761efa616028b255b4de58e9b5b87c5545 upstream.
When oops happens with panic_on_oops unset, the oops thread is killed by die() and system continues to run. In such case, guest should not report crash register data to host since system still runs. Check panic_on_oops and return directly in hyperv_report_panic() when the function is called in the die() and panic_on_oops is unset. Fix it.
Fixes: 7ed4325a44ea ("Drivers: hv: vmbus: Make panic reporting to be more useful") Signed-off-by: Tianyu Lan Tianyu.Lan@microsoft.com Reviewed-by: Michael Kelley mikelley@microsoft.com Link: https://lore.kernel.org/r/20200406155331.2105-7-Tianyu.Lan@microsoft.com Signed-off-by: Wei Liu wei.liu@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/hyperv/hv_init.c | 6 +++++- drivers/hv/vmbus_drv.c | 5 +++-- include/asm-generic/mshyperv.h | 2 +- 3 files changed, 9 insertions(+), 4 deletions(-)
--- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -19,6 +19,7 @@ #include <linux/mm.h> #include <linux/hyperv.h> #include <linux/slab.h> +#include <linux/kernel.h> #include <linux/cpuhotplug.h> #include <clocksource/hyperv_timer.h>
@@ -354,11 +355,14 @@ void hyperv_cleanup(void) } EXPORT_SYMBOL_GPL(hyperv_cleanup);
-void hyperv_report_panic(struct pt_regs *regs, long err) +void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die) { static bool panic_reported; u64 guest_id;
+ if (in_die && !panic_on_oops) + return; + /* * We prefer to report panic on 'die' chain as we have proper * registers to report, but if we miss it (e.g. on BUG()) we need --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -31,6 +31,7 @@ #include <linux/kdebug.h> #include <linux/efi.h> #include <linux/random.h> +#include <linux/kernel.h> #include <linux/syscore_ops.h> #include <clocksource/hyperv_timer.h> #include "hyperv_vmbus.h" @@ -75,7 +76,7 @@ static int hyperv_panic_event(struct not if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE && hyperv_report_reg()) { regs = current_pt_regs(); - hyperv_report_panic(regs, val); + hyperv_report_panic(regs, val, false); } return NOTIFY_DONE; } @@ -92,7 +93,7 @@ static int hyperv_die_event(struct notif * the notification here. */ if (hyperv_report_reg()) - hyperv_report_panic(regs, val); + hyperv_report_panic(regs, val, true); return NOTIFY_DONE; }
--- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -163,7 +163,7 @@ static inline int cpumask_to_vpset(struc return nr_bank; }
-void hyperv_report_panic(struct pt_regs *regs, long err); +void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die); void hyperv_report_panic_msg(phys_addr_t pa, size_t size); bool hv_is_hyperv_initialized(void); void hyperv_cleanup(void);