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Athira Rajeev f75e7d73bd powerpc/perf: Fix crash with is_sier_available when pmu is not set 
On systems without any specific PMU driver support registered, running
'perf record' with —intr-regs  will crash ( perf record -I <workload> ).

The relevant portion from crash logs and Call Trace:

Unable to handle kernel paging request for data at address 0x00000068
Faulting instruction address: 0xc00000000013eb18
Oops: Kernel access of bad area, sig: 11 [#1]
CPU: 2 PID: 13435 Comm: kill Kdump: loaded Not tainted 4.18.0-193.el8.ppc64le #1
NIP:  c00000000013eb18 LR: c000000000139f2c CTR: c000000000393d80
REGS: c0000004a07ab4f0 TRAP: 0300   Not tainted  (4.18.0-193.el8.ppc64le)
NIP [c00000000013eb18] is_sier_available+0x18/0x30
LR [c000000000139f2c] perf_reg_value+0x6c/0xb0
Call Trace:
[c0000004a07ab770] [c0000004a07ab7c8] 0xc0000004a07ab7c8 (unreliable)
[c0000004a07ab7a0] [c0000000003aa77c] perf_output_sample+0x60c/0xac0
[c0000004a07ab840] [c0000000003ab3f0] perf_event_output_forward+0x70/0xb0
[c0000004a07ab8c0] [c00000000039e208] __perf_event_overflow+0x88/0x1a0
[c0000004a07ab910] [c00000000039e42c] perf_swevent_hrtimer+0x10c/0x1d0
[c0000004a07abc50] [c000000000228b9c] __hrtimer_run_queues+0x17c/0x480
[c0000004a07abcf0] [c00000000022aaf4] hrtimer_interrupt+0x144/0x520
[c0000004a07abdd0] [c00000000002a864] timer_interrupt+0x104/0x2f0
[c0000004a07abe30] [c0000000000091c4] decrementer_common+0x114/0x120

When perf record session is started with "-I" option, capturing registers
on each sample calls is_sier_available() to check for the
SIER (Sample Instruction Event Register) availability in the platform.
This function in core-book3s accesses 'ppmu->flags'. If a platform specific
PMU driver is not registered, ppmu is set to NULL and accessing its
members results in a crash. Fix the crash by returning false in
is_sier_available() if ppmu is not set.

Fixes: 333804dc3b ("powerpc/perf: Update perf_regs structure to include SIER")
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1606185640-1720-1-git-send-email-atrajeev@linux.vnet.ibm.com
2020-12-04 01:01:09 +11:00
..
boot powerpc/boot: Make use of REL16 relocs in powerpc/boot/util.S 2020-12-04 01:00:44 +11:00
configs powerpc updates for 5.10 2020-10-16 12:21:15 -07:00
crypto crypto: powerpc/crc-vpmsum_test - Fix sparse endianness warning 2020-09-04 17:57:15 +10:00
include powerpc: Work around inline asm issues in alternate feature sections 2020-11-26 22:05:43 +11:00
kernel powerpc/ptrace: Hard wire PT_SOFTE value to 1 in gpr_get() too 2020-11-26 22:05:42 +11:00
kexec arch, drivers: replace for_each_membock() with for_each_mem_range() 2020-10-13 18:38:35 -07:00
kvm Merge branch 'fixes' into next 2020-11-25 23:17:31 +11:00
lib powerpc/64s: flush L1D after user accesses 2020-11-19 23:47:18 +11:00
math-emu
mm powerpc/mm: remove linear mapping if __add_pages() fails in arch_add_memory() 2020-11-19 16:56:59 +11:00
net bpf, powerpc: Fix misuse of fallthrough in bpf_jit_comp() 2020-09-29 16:39:11 +02:00
oprofile powerpc/oprofile: fix spelling mistake "contex" -> "context" 2020-08-25 01:31:33 +10:00
perf powerpc/perf: Fix crash with is_sier_available when pmu is not set 2020-12-04 01:01:09 +11:00
platforms Merge branch 'fixes' into next 2020-11-25 23:17:31 +11:00
purgatory powerpc/kexec_file: Enable early kernel OPAL calls 2020-07-29 23:47:55 +10:00
sysdev powerpc: sysdev: add missing iounmap() on error in mpic_msgr_probe() 2020-11-19 14:50:14 +11:00
tools powerpc/tools: Remove 90 line limit in checkpatch script 2020-09-08 22:57:11 +10:00
xmon powerpc/watchpoint: Add hw_len wherever missing 2020-09-15 22:13:20 +10:00
Kbuild
Kconfig powerpc updates for 5.10 2020-10-16 12:21:15 -07:00
Kconfig.debug powerpc: Remove Xilinx PPC405/PPC440 support 2020-05-28 23:24:34 +10:00
Makefile powerpc: Drop -me200 addition to build flags 2020-11-17 22:05:33 +11:00
Makefile.postlink powerpc: unrel_branch_check.sh: use nm to find symbol value 2020-09-02 11:00:22 +10:00