Ravi Bangoria wrote:
It may very well happen that branch instructions recorded by bhrb entries already get unmapped before they get processed by the kernel. Hence, trying to dereference such memory location will endup in a crash. Ex,Unable to handle kernel paging request for data at address 0xc008000019c41764 Faulting instruction address: 0xc000000000084a14 NIP [c000000000084a14] branch_target+0x4/0x70 LR [c0000000000eb828] record_and_restart+0x568/0x5c0 Call Trace: [c0000000000eb3b4] record_and_restart+0xf4/0x5c0 (unreliable) [c0000000000ec378] perf_event_interrupt+0x298/0x460 [c000000000027964] performance_monitor_exception+0x54/0x70 [c000000000009ba4] performance_monitor_common+0x114/0x120 Fix this by deferefencing them safely. Suggested-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com> Signed-off-by: Ravi Bangoria <ravi.bango...@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com> - Naveen
