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linux/arch/mips/kernel
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Matija Glavinic Pecotic 6f542ebeae MIPS: Fix race on setting and getting cpu_online_mask 
While testing cpu hoptlug (cpu down and up in loops) on kernel 4.4, it was
observed that occasionally check for cpu online will fail in kernel/cpu.c,
_cpu_up:

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/tree/kernel/cpu.c?h=v4.4.79#n485
 518        /* Arch-specific enabling code. */
 519        ret = __cpu_up(cpu, idle);
 520
 521        if (ret != 0)
 522                goto out_notify;
 523        BUG_ON(!cpu_online(cpu));

Reason is race between start_secondary and _cpu_up. cpu_callin_map is set
before cpu_online_mask. In __cpu_up, cpu_callin_map is waited for, but cpu
online mask is not, resulting in race in which secondary processor started
and set cpu_callin_map, but not yet set the online mask,resulting in above
BUG being hit.

Upstream differs in the area. cpu_online check is in bringup_wait_for_ap,
which is after cpu reached AP_ONLINE_IDLE,where secondary passed its start
function. Nonetheless, fix makes start_secondary safe and not depending on
other locks throughout the code. It protects as well against cpu_online
checks put in between sometimes in the future.

Fix this by moving completion after all flags are set.

Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Cc: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16925/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-08-07 11:57:30 +02:00
..
.gitignore
8250-platform.c
asm-offsets.c MIPS: IRQ Stack: Unwind IRQ stack onto task stack 2017-03-22 11:53:57 +01:00
binfmt_elfn32.c fs/binfmt: Convert obsolete cputime type to nsecs 2017-02-01 09:13:51 +01:00
binfmt_elfo32.c fs/binfmt: Convert obsolete cputime type to nsecs 2017-02-01 09:13:51 +01:00
bmips_5xxx_init.S MIPS: BMIPS: Make whitespacely correct. 2016-05-09 12:00:01 +02:00
bmips_vec.S MIPS: BMIPS: Add Whirlwind (BMIPS5200) initialization code 2016-05-09 12:00:01 +02:00
branch.c MIPS: Use pr_debug' for messages from __compute_return_epc_for_insn' 2017-06-29 02:42:27 +02:00
cacheinfo.c MIPS: Fix cacheinfo overflow 2017-02-13 18:57:34 +00:00
cevt-bcm1480.c MIPS: clockevent drivers: Set ->min_delta_ticks and ->max_delta_ticks 2017-04-14 13:11:16 -07:00
cevt-ds1287.c MIPS: clockevent drivers: Set ->min_delta_ticks and ->max_delta_ticks 2017-04-14 13:11:16 -07:00
cevt-gt641xx.c MIPS: clockevent drivers: Set ->min_delta_ticks and ->max_delta_ticks 2017-04-14 13:11:16 -07:00
cevt-r4k.c MIPS: cevt-r4k: Fix out-of-bounds array access 2017-04-10 13:31:12 +02:00
cevt-sb1250.c MIPS: clockevent drivers: Set ->min_delta_ticks and ->max_delta_ticks 2017-04-14 13:11:16 -07:00
cevt-txx9.c MIPS: clockevent drivers: Set ->min_delta_ticks and ->max_delta_ticks 2017-04-14 13:11:16 -07:00
cmpxchg.c MIPS: cmpxchg: Implement 1 byte & 2 byte cmpxchg() 2017-06-29 02:42:25 +02:00
cps-vec-ns16550.S MIPS: CPS: Early debug using an ns16550-compatible UART 2015-11-11 08:34:25 +01:00
cps-vec.S MIPS: CPS: Handle spurious VP starts more gracefully 2017-06-29 02:42:28 +02:00
cpu-bugs64.c MIPS: Fix printk continuations in cpu-bugs64.c 2017-01-24 18:30:34 +01:00
cpu-probe.c MIPS: MIPS16e2: Identify ASE presence 2017-07-05 14:06:44 +02:00
crash_dump.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
crash.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
csrc-bcm1480.c clocksource: Use a plain u64 instead of cycle_t 2016-12-25 11:04:12 +01:00
csrc-ioasic.c clocksource: Use a plain u64 instead of cycle_t 2016-12-25 11:04:12 +01:00
csrc-r4k.c clocksource: Use a plain u64 instead of cycle_t 2016-12-25 11:04:12 +01:00
csrc-sb1250.c clocksource: Use a plain u64 instead of cycle_t 2016-12-25 11:04:12 +01:00
early_printk_8250.c
early_printk.c
elf.c MIPS: Avoid BUG warning in arch_check_elf 2017-04-12 15:22:13 +02:00
entry.S MIPS: Fix IRQ tracing & lockdep when rescheduling 2017-06-30 04:40:18 +02:00
ftrace.c MIPS: ftrace: fix init functions tracing 2017-06-08 14:51:59 +02:00
genex.S MIPS: IRQ Stack: Unwind IRQ stack onto task stack 2017-03-22 11:53:57 +01:00
gpio_txx9.c MIPS: txx9: switch to gpiochip_add_data() 2016-02-19 09:51:44 +01:00
head.S MIPS: head: Reorder instructions missing a delay slot 2017-06-27 23:35:21 +02:00
i8253.c
idle.c MIPS: Loongson: Add Loongson-3A R2 basic support 2016-05-13 14:02:14 +02:00
irq_txx9.c
irq-gt641xx.c
irq-msc01.c
irq-rm7000.c
irq.c MIPS: Introduce irq_stack 2017-01-03 16:34:34 +01:00
jump_label.c jump_label: Reorder hotplug lock and jump_label_lock 2017-05-26 10:10:45 +02:00
kgdb.c MIPS: KGDB: Use kernel context for sleeping threads 2017-04-12 22:29:22 +02:00
kprobes.c MIPS: tracing: disable uprobe/kprobe on compact branch instructions 2016-10-06 17:37:40 +02:00
linux32.c MIPS: Return directly in 32_mmap2() 2017-01-25 02:51:11 +01:00
machine_kexec.c MIPS: kexec: add debug info about the new kexec'ed image 2017-01-03 16:34:46 +01:00
Makefile MIPS: cmpxchg: Implement 1 byte & 2 byte xchg() 2017-06-29 02:42:25 +02:00
mcount.S MIPS: Export _mcount alongside its definition 2017-01-03 16:34:49 +01:00
mips_machine.c
mips-cm.c MIPS: CM: WARN on attempt to lock invalid VP, not BUG 2017-06-29 02:42:28 +02:00
mips-cpc.c MIPS: CPC: Provide default mips_cpc_default_phys_base to ignore CPC 2016-11-04 00:17:46 +01:00
mips-mt-fpaff.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h> 2017-03-02 08:42:35 +01:00
mips-mt.c
mips-r2-to-r6-emul.c Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-05-12 09:56:30 -07:00
module.c Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-07-15 10:59:54 -07:00
octeon_switch.S MIPS: Fix octeon FP context switch handling 2015-10-02 19:16:06 +02:00
perf_event_mipsxx.c MIPS: perf: add I6500 handling 2017-06-28 12:22:39 +02:00
perf_event.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
pm-cps.c MIPS: pm-cps: Drop manual cache-line alignment of ready_count 2017-06-30 04:38:55 +02:00
pm.c MIPS: Fix watchpoint restoration 2016-05-09 12:00:02 +02:00
probes-common.h MIPS: tracing: disable uprobe/kprobe on compact branch instructions 2016-10-06 17:37:40 +02:00
proc.c MIPS: Fix MIPS I ISA /proc/cpuinfo reporting 2017-07-11 14:13:50 +02:00
process.c kthread: fix boot hang (regression) on MIPS/OpenRISC 2017-05-29 09:40:54 -07:00
prom.c MIPS: Use early_init_fdt_reserve_self to protect DTB location 2017-01-03 16:34:45 +01:00
ptrace32.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
ptrace.c MIPS: Traced negative syscalls should return -ENOSYS 2017-07-11 14:13:06 +02:00
r4k_fpu.S MIPS: Use copy_s.fmt rather than copy_u.fmt 2016-05-09 12:00:04 +02:00
r4k_switch.S MIPS: Remove dead define of ST_OFF 2017-04-12 13:52:21 +02:00
r2300_fpu.S MIPS: Correct MIPS I FP sigcontext layout 2016-11-04 01:39:23 +01:00
r2300_switch.S MIPS: Export _save_fp & _save_msa alongside their definitions 2017-01-03 16:34:49 +01:00
r6000_fpu.S MIPS: Fix ISA I/II FP signal context offsets 2016-11-04 01:38:52 +01:00
relocate_kernel.S MIPS: Replace add and sub instructions in relocate_kernel.S with addiu 2015-08-03 15:26:30 +02:00
relocate.c MIPS: KASLR: Add missing header files 2017-04-12 17:02:04 +02:00
reset.c MIPS: Provide fallback reboot/poweroff/halt implementations 2015-04-01 17:21:58 +02:00
rtlx-cmp.c
rtlx-mt.c
rtlx.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
scall32-o32.S MIPS: Save static registers before sysmips 2017-06-28 12:22:40 +02:00
scall64-64.S MIPS: Save static registers before sysmips 2017-06-28 12:22:40 +02:00
scall64-n32.S MIPS: Save static registers before sysmips 2017-06-28 12:22:40 +02:00
scall64-o32.S MIPS: Save static registers before sysmips 2017-06-28 12:22:40 +02:00
segment.c MIPS: Print segment physical address when EU=1 2016-07-28 11:44:30 +02:00
setup.c MIPS: cmdline: Add support for 'memmap' parameter 2017-06-29 02:42:23 +02:00
signal32.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
signal_n32.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
signal_o32.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
signal-common.h MIPS: Save MSA extended context around signals 2015-09-03 12:07:59 +02:00
signal.c Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2016-08-06 09:13:11 -04:00
smp-bmips.c MIPS: Add missing include files 2017-03-08 10:38:06 +01:00
smp-cmp.c MIPS: Make smp CMP, CPS and MT use the new generic IPI functions 2016-02-25 10:56:58 +01:00
smp-cps.c MIPS: CPS: Handle cores not powering down more gracefully 2017-06-29 02:42:28 +02:00
smp-mt.c MIPS: smp-mt: Use CPU interrupt controller IPI IRQ domain support 2017-04-12 23:13:13 +02:00
smp-up.c
smp.c MIPS: Fix race on setting and getting cpu_online_mask 2017-08-07 11:57:30 +02:00
spinlock_test.c MIPS: Declare mips_debugfs_dir in a header 2015-10-26 09:49:42 +01:00
spram.c MIPS: Add P6600 cases to CPU switch statements 2016-05-13 14:01:52 +02:00
stacktrace.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
sync-r4k.c MIPS: sync-r4k: Fix KERN_CONT fallout 2017-02-13 18:58:39 +00:00
syscall.c MIPS: Branch straight to ll in mips_atomic_set() 2017-06-28 12:22:40 +02:00
sysrq.c MIPS: Refactor dumping of TLB registers for r3k/r4k 2015-09-03 12:07:45 +02:00
time.c KVM: MIPS: Implement VZ support 2017-03-28 14:53:54 +01:00
topology.c
traps.c lib/extable.c: use bsearch() library function in search_extable() 2017-07-10 16:32:35 -07:00
unaligned.c MIPS: MIPS16e2: Subdecode extended LWSP/SWSP instructions 2017-07-05 14:07:20 +02:00
uprobes.c MIPS: uprobes: Remove __weak attribute from arch_uprobe_copy_ixol. 2017-01-03 16:34:48 +01:00
vdso.c userfaultfd: non-cooperative: add event for memory unmaps 2017-02-24 17:46:55 -08:00
vmlinux.lds.S debug: Fix __bug_table[] in arch linker scripts 2017-04-03 10:22:40 +02:00
vpe-cmp.c
vpe-mt.c
vpe.c module: use a structure to encapsulate layout. 2015-12-04 22:46:25 +01:00
watch.c MIPS: Add and use watch register field definitions 2016-05-13 14:02:13 +02:00