linux/arch
Nicholas Piggin ac61c11566 powerpc: Fix smp_send_stop NMI IPI handling
The NMI IPI handler for a receiving CPU increments nmi_ipi_busy_count
over the handler function call, which causes later smp_send_nmi_ipi()
callers to spin until the call is finished.

The stop_this_cpu() function never returns, so the busy count is never
decremeted, which can cause the system to hang in some cases. For
example panic() will call smp_send_stop() early on which calls
stop_this_cpu() on other CPUs, then later in the reboot path,
pnv_restart() will call smp_send_stop() again, which hangs.

Fix this by adding a special case to the stop_this_cpu() handler to
decrement the busy count, because it will never return.

Now that the NMI/non-NMI versions of stop_this_cpu() are different,
split them out into separate functions rather than doing #ifdef tricks
to share the body between the two functions.

Fixes: 6bed323762 ("powerpc: use NMI IPI for smp_send_stop")
Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out the functions, tweak change log a bit]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-04-25 20:38:08 +10:00
..
alpha mm: introduce MAP_FIXED_NOREPLACE 2018-04-11 10:28:38 -07:00
arc kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers 2018-04-07 19:04:02 +09:00
arm Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
arm64 arm64: signal: don't force known signals to SIGKILL 2018-04-18 15:13:27 +01:00
c6x c6x: pass endianness info to sparse 2018-04-10 09:58:58 -04:00
h8300 h8300: remove extraneous __BIG_ENDIAN definition 2018-03-22 17:07:01 -07:00
hexagon
ia64 pci-v4.17-changes 2018-04-06 18:31:06 -07:00
m68k Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu 2018-04-09 09:15:46 -07:00
microblaze Microblaze patches for 4.17-rc1 2018-04-12 10:18:02 -07:00
mips MIPS fixes for 4.17-rc2 2018-04-20 08:25:31 -07:00
nds32 page cache: use xa_lock 2018-04-11 10:28:39 -07:00
nios2 nios2 update for v4.17-rc1 2018-04-11 16:02:18 -07:00
openrisc OpenRISC updates for v4.17 2018-04-15 12:27:58 -07:00
parisc parisc: Fix missing binfmt_elf32.o build error 2018-04-14 11:17:59 +02:00
powerpc powerpc: Fix smp_send_stop NMI IPI handling 2018-04-25 20:38:08 +10:00
riscv RISC-V changes for 4.17 2018-04-04 16:43:47 -07:00
s390 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-04-20 09:15:14 -07:00
sh Merge branch 'akpm' (patches from Andrew) 2018-04-14 08:50:50 -07:00
sparc Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
um Merge git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml 2018-04-11 16:36:47 -07:00
unicore32 unicore32: turn flush_dcache_mmap_lock into a no-op 2018-04-11 10:28:39 -07:00
x86 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-22 11:40:52 -07:00
xtensa mm: introduce MAP_FIXED_NOREPLACE 2018-04-11 10:28:38 -07:00
.gitignore
Kconfig kbuild: remove incremental linking option 2018-03-26 02:01:19 +09:00