Ravi Bangoria bf05fc25f2 powerpc/perf: Fix oops when kthread execs user process ... When a kthread calls call_usermodehelper() the steps are: 1. allocate current->mm 2. load_elf_binary() 3. populate current->thread.regs While doing this, interrupts are not disabled. If there is a perf interrupt in the middle of this process (i.e. step 1 has completed but not yet reached to step 3) and if perf tries to read userspace regs, kernel oops with following log: Unable to handle kernel paging request for data at address 0x00000000 Faulting instruction address: 0xc0000000000da0fc ... Call Trace: perf_output_sample_regs+0x6c/0xd0 perf_output_sample+0x4e4/0x830 perf_event_output_forward+0x64/0x90 __perf_event_overflow+0x8c/0x1e0 record_and_restart+0x220/0x5c0 perf_event_interrupt+0x2d8/0x4d0 performance_monitor_exception+0x54/0x70 performance_monitor_common+0x158/0x160 --- interrupt: f01 at avtab_search_node+0x150/0x1a0 LR = avtab_search_node+0x100/0x1a0 ... load_elf_binary+0x6e8/0x15a0 search_binary_handler+0xe8/0x290 do_execveat_common.isra.14+0x5f4/0x840 call_usermodehelper_exec_async+0x170/0x210 ret_from_kernel_thread+0x5c/0x7c Fix it by setting abi to PERF_SAMPLE_REGS_ABI_NONE when userspace pt_regs are not set. Fixes: ed4a4ef85c ("powerpc/perf: Add support for sampling interrupt register state") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>		2017-06-16 21:02:46 +10:00
..
req-gen
8xx-pmu.c	powerpc/8xx: Perf events on PPC 8xx	2017-01-26 17:49:34 -06:00
bhrb.S
callchain.c
core-book3s.c	powerpc/perf: Support to export MMCRA[TEC*] field to userspace	2017-04-19 20:00:22 +10:00
core-fsl-emb.c
e500-pmu.c
e6500-pmu.c
hv-24x7-catalog.h
hv-24x7-domains.h
hv-24x7.c
hv-24x7.h
hv-common.c
hv-common.h
hv-gpci-requests.h
hv-gpci.c
hv-gpci.h
isa207-common.c	powerpc/perf: Support to export MMCRA[TEC*] field to userspace	2017-04-19 20:00:22 +10:00
isa207-common.h	powerpc/perf: Support to export MMCRA[TEC*] field to userspace	2017-04-19 20:00:22 +10:00
Makefile	powerpc/8xx: Perf events on PPC 8xx	2017-01-26 17:49:34 -06:00
mpc7450-pmu.c
perf_regs.c	powerpc/perf: Fix oops when kthread execs user process	2017-06-16 21:02:46 +10:00
power4-pmu.c
power5-pmu.c
power5+-pmu.c
power6-pmu.c
power7-events-list.h
power7-pmu.c
power8-events-list.h	powerpc/perf: Add Power8 mem_access event to sysfs	2017-04-19 20:00:23 +10:00
power8-pmu.c	powerpc/perf: Add Power8 mem_access event to sysfs	2017-04-19 20:00:23 +10:00
power9-events-list.h	powerpc/perf: Add PM_INST_DISP event to Power9 event list	2017-02-17 21:48:52 +11:00
power9-pmu.c	powerpc/perf: Fix Power9 test_adder fields	2017-06-06 21:21:19 +10:00
ppc970-pmu.c