mirror_ubuntu-kernels/arch/powerpc/kernel
Sourabh Jain ba608c4fa1 powerpc/fadump: fix race between pstore write and fadump crash trigger
When we enter into fadump crash path via system reset we fail to update
the pstore.

On the system reset path we first update the pstore then we go for fadump
crash. But the problem here is when all the CPUs try to get the pstore
lock to initiate the pstore write, only one CPUs will acquire the lock
and proceed with the pstore write. Since it in NMI context CPUs that fail
to get lock do not wait for their turn to write to the pstore and simply
proceed with the next operation which is fadump crash. One of the CPU who
proceeded with fadump crash path triggers the crash and does not wait for
the CPU who gets the pstore lock to complete the pstore update.

Timeline diagram to depicts the sequence of events that leads to an
unsuccessful pstore update when we hit fadump crash path via system reset.

                 1    2     3    ...      n   CPU Threads
                 |    |     |             |
                 |    |     |             |
 Reached to   -->|--->|---->| ----------->|
 system reset    |    |     |             |
 path            |    |     |             |
                 |    |     |             |
 Try to       -->|--->|---->|------------>|
 acquire the     |    |     |             |
 pstore lock     |    |     |             |
                 |    |     |             |
                 |    |     |             |
 Got the      -->| +->|     |             |<-+
 pstore lock     | |  |     |             |  |-->  Didn't get the
                 | --------------------------+     lock and moving
                 |    |     |             |        ahead on fadump
                 |    |     |             |        crash path
                 |    |     |             |
  Begins the  -->|    |     |             |
  process to     |    |     |             |<-- Got the chance to
  update the     |    |     |             |    trigger the crash
  pstore         | -> |     |    ... <-   |
                 | |  |     |         |   |
                 | |  |     |         |   |<-- Triggers the
                 | |  |     |         |   |    crash
                 | |  |     |         |   |      ^
                 | |  |     |         |   |      |
  Writing to  -->| |  |     |         |   |      |
  pstore         | |  |     |         |   |      |
                   |                  |          |
       ^           |__________________|          |
       |               CPU Relax                 |
       |                                         |
       +-----------------------------------------+
                          |
                          v
            Race: crash triggered before pstore
                  update completes

To avoid this race condition a barrier is added on crash_fadump path, it
prevents the CPU to trigger the crash until all the online CPUs completes
their task.

A barrier is added to make sure all the secondary CPUs hit the
crash_fadump function before we initiates the crash. A timeout is kept to
ensure the primary CPU (one who initiates the crash) do not wait for
secondary CPUs indefinitely.

Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200713052435.183750-1-sourabhjain@linux.ibm.com
2020-07-16 13:12:44 +10:00
..
ptrace powerpc/watchpoint: Use builtin ALIGN*() macros 2020-05-19 00:11:05 +10:00
syscalls vfs: add faccessat2 syscall 2020-05-14 16:44:25 +02:00
trace maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00
vdso32 powerpc/vdso32: Fallback on getres syscall when clock is unknown 2020-05-11 19:24:29 +10:00
vdso64 powerpc/vdso64: Switch from __get_datapage() to get_datapage inline macro 2020-07-15 12:04:40 +10:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
align.c powerpc: Define and use get_user_instr() et. al. 2020-05-19 00:10:37 +10:00
asm-offsets.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
audit.c
btext.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
cacheinfo.c powerpc/cacheinfo: Add per cpu per index shared_cpu_list 2020-07-15 11:07:20 +10:00
cacheinfo.h powerpc/cacheinfo: add cacheinfo_teardown, cacheinfo_rebuild 2019-06-15 16:52:06 +10:00
compat_audit.c
cpu_setup_6xx.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
cpu_setup_44x.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cpu_setup_fsl_booke.S powerpc/booke: Spelling s/date/data/ 2019-11-17 01:56:31 -06:00
cpu_setup_pa6t.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
cpu_setup_power.S powerpc: Add POWER10 architected mode 2020-06-02 20:59:20 +10:00
cpu_setup_ppc970.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cputable.c powerpc: Add POWER10 architected mode 2020-06-02 20:59:20 +10:00
crash_dump.c powerpc: Add prefixed instructions to instruction data type 2020-05-19 00:10:39 +10:00
dawr.c powerpc/watchpoint: Disable all available watchpoints when !dawr_force_enable 2020-05-19 00:11:05 +10:00
dbell.c KVM: PPC: Book3S HV: use smp_mb() when setting/clearing host_ipi flag 2019-09-24 12:46:26 +10:00
dma-iommu.c powerpc updates for 5.4 2019-09-20 11:48:06 -07:00
dma-mask.c dma-mapping, powerpc: simplify the arch dma_set_mask override 2019-02-18 22:41:03 +11:00
dma-swiotlb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
dt_cpu_ftrs.c powerpc/mm: Enable radix GTSE only if supported. 2020-07-16 13:00:21 +10:00
early_32.c powerpc/fsl_booke/32: implement KASLR infrastructure 2019-11-13 19:27:40 +11:00
eeh_cache.c powerpc/eeh_cache: Don't use pci_dn when inserting new ranges 2020-01-23 21:31:18 +11:00
eeh_dev.c powerpc/eeh: Add bdfn field to eeh_dev 2019-08-22 23:12:46 +10:00
eeh_driver.c powerpc/eeh: Fix deadlock handling dead PHB 2020-02-17 12:47:05 +11:00
eeh_event.c powerpc/eeh: Fix build with STACKTRACE=n 2019-09-14 00:01:14 +10:00
eeh_pe.c powerpc/eeh: Clean up EEH PEs after recovery finishes 2019-09-05 14:22:37 +10:00
eeh_sysfs.c powerpc/eeh_sysfs: Make clearing EEH_DEV_SYSFS saner 2020-01-23 21:31:19 +11:00
eeh.c powerpc/eeh: Release EEH device state synchronously 2020-05-18 21:58:44 +10:00
entry_32.S powerpc/entry32: Blacklist exception exit points for kprobe. 2020-06-02 20:59:13 +10:00
entry_64.S powerpc/64s: Move branch cache flushing bcctr variant to ppc-ops.h 2020-07-16 13:12:32 +10:00
epapr_hcalls.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
epapr_paravirt.c powerpc: Use a datatype for instructions 2020-05-19 00:10:37 +10:00
exceptions-64e.S powerpc/64s: Implement interrupt exit logic in C 2020-04-01 13:42:14 +11:00
exceptions-64s.S powerpc/64s: Fix KVM interrupt using wrong save area 2020-06-16 12:52:43 +10:00
fadump.c powerpc/fadump: fix race between pstore write and fadump crash trigger 2020-07-16 13:12:44 +10:00
firmware.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
fpu.S powerpc: re-initialise lazy FPU/VEC counters on every fault 2020-07-16 13:00:24 +10:00
fsl_booke_entry_mapping.S powerpc/fsl_booke/32: implement KASLR infrastructure 2019-11-13 19:27:40 +11:00
head_8xx.S mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
head_32.h Merge branch 'fixes' into next 2020-03-10 15:16:42 +11:00
head_32.S mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
head_40x.S mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
head_44x.S mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
head_64.S powerpc/64: Don't initialise init_task->thread.regs 2020-05-15 11:58:54 +10:00
head_booke.h powerpc: Replace _ALIGN_UP() by ALIGN() 2020-05-11 23:15:15 +10:00
head_fsl_booke.S mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
hw_breakpoint.c powerpc/watchpoint: Don't allow concurrent perf and ptrace events 2020-05-19 00:14:45 +10:00
idle_6xx.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
idle_book3e.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
idle_book3s.S powerpc/64s: Reimplement power4_idle code in C 2020-01-16 14:59:37 +10:00
idle_e500.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
idle.c powerpc/64s: Reimplement power4_idle code in C 2020-01-16 14:59:37 +10:00
ima_arch.c powerpc/ima: Fix secure boot rules in ima arch policy 2020-05-07 17:25:54 +10:00
io-workarounds.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
io.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
iomap.c
iommu.c Merge branch 'topic/ppc-kvm' into next 2019-08-30 09:52:57 +10:00
irq.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
isa-bridge.c powerpc: remove __ioremap_at and __iounmap_at 2020-06-02 10:59:10 -07:00
jump_label.c powerpc: Use a datatype for instructions 2020-05-19 00:10:37 +10:00
kgdb.c maccess: make get_kernel_nofault() check for minimal type compatibility 2020-06-18 12:10:37 -07:00
kprobes-ftrace.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
kprobes.c maccess: rename probe_kernel_address to get_kernel_nofault 2020-06-18 11:14:40 -07:00
kvm_emul.S powerpc/kvm: Add ifdefs around template code 2019-09-14 00:04:40 +10:00
kvm.c powerpc/kvm: Explicitly mark kvm guest code as __init 2019-09-14 00:04:40 +10:00
l2cr_6xx.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
legacy_serial.c tty/serial: Migrate 8250_fsl to use has_sysrq 2019-12-18 15:04:42 +01:00
Makefile powerpc/64s: Disable sanitisers for C syscall/interrupt entry/exit code 2020-05-29 21:12:09 +10:00
mce_power.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
mce.c powerpc/64s: machine check do not trace real-mode handler 2020-05-19 00:10:34 +10:00
misc_32.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
misc_64.S Merge branch 'topic/kaslr-book3e32' into next 2019-11-14 19:23:33 +11:00
misc.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
module_32.c powerpc: module_[32|64].c: replace swap function with built-in one 2020-05-11 23:15:14 +10:00
module_64.c maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00
module.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
module.lds
msi.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
note.S powerpc: Add PowerPC Capabilities ELF note 2019-08-30 09:40:15 +10:00
nvram_64.c powerpc updates for 5.8 2020-06-05 12:39:30 -07:00
of_platform.c powerpc/eeh: Make early EEH init pseries specific 2020-03-25 12:09:39 +11:00
optprobes_head.S powerpc: Add prefixed instructions to instruction data type 2020-05-19 00:10:39 +10:00
optprobes.c powerpc: Add ppc_inst_as_u64() 2020-05-26 23:36:57 +10:00
paca.c powerpc/pseries/svm: Drop unused align argument in alloc_shared_lppaca() function 2020-06-22 10:37:59 +10:00
pci_32.c powerpc/64: Adjust order in pcibios_init() 2019-08-22 23:11:48 +10:00
pci_64.c powerpc updates for 5.8 2020-06-05 12:39:30 -07:00
pci_dn.c powerpc/pcidn: Warn when sriov pci_dn management is used incorrectly 2020-01-23 21:31:19 +11:00
pci_of_scan.c powerpc/pci: Remove pcibios_setup_bus_devices() 2020-01-06 16:25:29 +11:00
pci-common.c powerpc updates for 5.7 2020-04-05 11:12:59 -07:00
pci-hotplug.c powerpc/eeh: Release EEH device state synchronously 2020-05-18 21:58:44 +10:00
pmc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ppc32.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ppc_save_regs.S powerpc: Improve ppc_save_regs() 2020-04-04 21:40:57 +11:00
proc_powerpc.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
process.c powerpc/64s: Fix restore_math unnecessarily changing MSR 2020-07-16 13:00:24 +10:00
prom_init_check.sh powerpc/prom_init: Undo relocation before entering secure mode 2019-10-29 15:12:17 +11:00
prom_init.c powerpc/mm: Enable radix GTSE only if supported. 2020-07-16 13:00:21 +10:00
prom_parse.c
prom.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
reloc_32.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
reloc_64.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
rtas_flash.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
rtas_pci.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
rtas-proc.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
rtas-rtc.c powerpc: use time64_t in read_persistent_clock 2018-06-03 20:43:33 +10:00
rtas.c powerpc/rtas: don't online CPUs for partition suspend 2020-07-16 13:12:35 +10:00
rtasd.c powerpc/rtasd: simplify handle_rtas_event(), emit message on events 2020-07-16 13:12:38 +10:00
secure_boot.c powerpc: Detect the trusted boot state of the system 2019-11-12 12:25:49 +11:00
security.c powerpc/security: Allow for processors that flush the link stack using the special bcctr 2020-07-16 13:12:32 +10:00
secvar-ops.c powerpc/powernv: Add OPAL API interface to access secure variable 2019-11-13 00:33:22 +11:00
secvar-sysfs.c powerpc: expose secure variables to userspace via sysfs 2019-11-13 00:33:22 +11:00
setup_32.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
setup_64.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
setup-common.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
setup.h powerpc/64: Prevent stack protection in early boot 2020-03-25 12:09:38 +11:00
signal_32.c powerpc/signal_32: Simplify loop in PPC64 save_general_regs() 2020-07-15 12:04:40 +10:00
signal_64.c powerpc/signal64: Don't opencode page prefaulting 2020-07-15 12:04:40 +10:00
signal.c powerpc/watchpoint: Convert thread_struct->hw_brk to an array 2020-05-19 00:11:05 +10:00
signal.h powerpc/64/sycall: Implement syscall entry/exit logic in C 2020-04-01 13:42:13 +11:00
smp-tbsync.c
smp.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
stacktrace.c kernel: rename show_stack_loglvl() => show_stack() 2020-06-09 09:39:13 -07:00
suspend.c PM: hibernate: powerpc: Expose pfn_is_nosave() prototype 2019-06-14 10:48:56 +02:00
swsusp_32.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
swsusp_64.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 2019-06-19 17:11:22 +02:00
swsusp_asm64.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 2019-06-19 17:11:22 +02:00
swsusp_booke.S
swsusp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sys_ppc32.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
syscall_64.c powerpc/64s: Fix restore_math unnecessarily changing MSR 2020-07-16 13:00:24 +10:00
syscalls.c y2038: syscalls: change remaining timeval to __kernel_old_timeval 2019-11-15 14:38:29 +01:00
sysfs.c powerpc/sysfs: Show idle_purr and idle_spurr for every CPU 2020-04-30 12:35:26 +10:00
systbl_chk.sh treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
systbl.S powerpc/64/sycall: Implement syscall entry/exit logic in C 2020-04-01 13:42:13 +11:00
tau_6xx.c powerpc/tau: Make some function static 2018-05-25 12:04:44 +10:00
time.c Revert "powerpc/64: irq_work avoid interrupt when called with hardware irqs enabled" 2020-04-03 16:55:34 +11:00
tm.S powerpc/tm: update comment about interrupt re-entrancy 2019-07-02 21:39:49 +10:00
traps.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
ucall.S powerpc/kernel: Add ucall_norets() ultravisor call handler 2019-08-30 09:40:15 +10:00
udbg_16550.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
udbg.c powerpc/udbg: Make it safe to call udbg_printf() always 2019-10-11 19:33:25 +11:00
uprobes.c powerpc: Add ppc_inst_next() 2020-05-26 23:36:51 +10:00
vdso.c mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
vecemu.c powerpc: Define and use get_user_instr() et. al. 2020-05-19 00:10:37 +10:00
vector.S powerpc: re-initialise lazy FPU/VEC counters on every fault 2020-07-16 13:00:24 +10:00
vmlinux.lds.S powerpc updates for 5.8 2020-06-05 12:39:30 -07:00
watchdog.c powerpc/watchdog: Use hrtimers for per-CPU heartbeat 2019-04-30 11:31:02 +10:00