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linux-sg2042/arch/parisc/kernel
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John David Anglin 741dc7bf1c parisc: Fix races in parisc_setup_cache_timing() 
Helge reported to me the following startup crash:

[    0.000000] Linux version 4.8.0-1-parisc64-smp (debian-kernel@lists.debian.org) (gcc version 5.4.1 20161019 (GCC) ) #1 SMP Debian 4.8.7-1 (2016-11-13)
[    0.000000] The 64-bit Kernel has started...
[    0.000000] Kernel default page size is 4 KB. Huge pages enabled with 1 MB physical and 2 MB virtual size.
[    0.000000] Determining PDC firmware type: System Map.
[    0.000000] model 9000/785/J5000
[    0.000000] Total Memory: 2048 MB
[    0.000000] Memory: 2018528K/2097152K available (9272K kernel code, 3053K rwdata, 1319K rodata, 1024K init, 840K bss, 78624K reserved, 0K cma-reserved)
[    0.000000] virtual kernel memory layout:
[    0.000000]     vmalloc : 0x0000000000008000 - 0x000000003f000000   (1007 MB)
[    0.000000]     memory  : 0x0000000040000000 - 0x00000000c0000000   (2048 MB)
[    0.000000]       .init : 0x0000000040100000 - 0x0000000040200000   (1024 kB)
[    0.000000]       .data : 0x0000000040b0e000 - 0x0000000040f533e0   (4372 kB)
[    0.000000]       .text : 0x0000000040200000 - 0x0000000040b0e000   (9272 kB)
[    0.768910] Brought up 1 CPUs
[    0.992465] NET: Registered protocol family 16
[    2.429981] Releasing cpu 1 now, hpa=fffffffffffa2000
[    2.635751] CPU(s): 2 out of 2 PA8500 (PCX-W) at 440.000000 MHz online
[    2.726692] Setting cache flush threshold to 1024 kB
[    2.729932] Not-handled unaligned insn 0x43ffff80
[    2.798114] Setting TLB flush threshold to 140 kB
[    2.928039] Unaligned handler failed, ret = -1
[    3.000419]       _______________________________
[    3.000419]      < Your System ate a SPARC! Gah! >
[    3.000419]       -------------------------------
[    3.000419]              \   ^__^
[    3.000419]                  (__)\       )\/\
[    3.000419]                   U  ||----w |
[    3.000419]                      ||     ||
[    9.340055] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.8.0-1-parisc64-smp #1 Debian 4.8.7-1
[    9.448082] task: 00000000bfd48060 task.stack: 00000000bfd50000
[    9.528040]
[   10.760029] IASQ: 0000000000000000 0000000000000000 IAOQ: 000000004025d154 000000004025d158
[   10.868052]  IIR: 43ffff80    ISR: 0000000000340000  IOR: 000001ff54150960
[   10.960029]  CPU:        1   CR30: 00000000bfd50000 CR31: 0000000011111111
[   11.052057]  ORIG_R28: 000000004021e3b4
[   11.100045]  IAOQ[0]: irq_exit+0x94/0x120
[   11.152062]  IAOQ[1]: irq_exit+0x98/0x120
[   11.208031]  RP(r2): irq_exit+0xb8/0x120
[   11.256074] Backtrace:
[   11.288067]  [<00000000402cd944>] cpu_startup_entry+0x1e4/0x598
[   11.368058]  [<0000000040109528>] smp_callin+0x2c0/0x2f0
[   11.436308]  [<00000000402b53fc>] update_curr+0x18c/0x2d0
[   11.508055]  [<00000000402b73b8>] dequeue_entity+0x2c0/0x1030
[   11.584040]  [<00000000402b3cc0>] set_next_entity+0x80/0xd30
[   11.660069]  [<00000000402c1594>] pick_next_task_fair+0x614/0x720
[   11.740085]  [<000000004020dd34>] __schedule+0x394/0xa60
[   11.808054]  [<000000004020e488>] schedule+0x88/0x118
[   11.876039]  [<0000000040283d3c>] rescuer_thread+0x4d4/0x5b0
[   11.948090]  [<000000004028fc4c>] kthread+0x1ec/0x248
[   12.016053]  [<0000000040205020>] end_fault_vector+0x20/0xc0
[   12.092239]  [<00000000402050c0>] _switch_to_ret+0x0/0xf40
[   12.164044]
[   12.184036] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.8.0-1-parisc64-smp #1 Debian 4.8.7-1
[   12.244040] Backtrace:
[   12.244040]  [<000000004021c480>] show_stack+0x68/0x80
[   12.244040]  [<00000000406f332c>] dump_stack+0xec/0x168
[   12.244040]  [<000000004021c74c>] die_if_kernel+0x25c/0x430
[   12.244040]  [<000000004022d320>] handle_unaligned+0xb48/0xb50
[   12.244040]
[   12.632066] ---[ end trace 9ca05a7215c7bbb2 ]---
[   12.692036] Kernel panic - not syncing: Attempted to kill the idle task!

We have the insn 0x43ffff80 in IIR but from IAOQ we should have:
   4025d150:   0f f3 20 df     ldd,s r19(r31),r31
   4025d154:   0f 9f 00 9c     ldw r31(ret0),ret0
   4025d158:   bf 80 20 58     cmpb,*<> r0,ret0,4025d18c <irq_exit+0xcc>

Cpu0 has just completed running parisc_setup_cache_timing:

[    2.429981] Releasing cpu 1 now, hpa=fffffffffffa2000
[    2.635751] CPU(s): 2 out of 2 PA8500 (PCX-W) at 440.000000 MHz online
[    2.726692] Setting cache flush threshold to 1024 kB
[    2.729932] Not-handled unaligned insn 0x43ffff80
[    2.798114] Setting TLB flush threshold to 140 kB
[    2.928039] Unaligned handler failed, ret = -1

From the backtrace, cpu1 is in smp_callin:

void __init smp_callin(void)
{
       int slave_id = cpu_now_booting;

       smp_cpu_init(slave_id);
       preempt_disable();

       flush_cache_all_local(); /* start with known state */
       flush_tlb_all_local(NULL);

       local_irq_enable();  /* Interrupts have been off until now */

       cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

So, it has just flushed its caches and the TLB. It would seem either the
flushes in parisc_setup_cache_timing or smp_callin have corrupted kernel
memory.

The attached patch reworks parisc_setup_cache_timing to remove the races
in setting the cache and TLB flush thresholds. It also corrects the
number of bytes flushed in the TLB calculation.

The patch flushes the cache and TLB on cpu0 before starting the
secondary processors so that they are started from a known state.

Tested with a few reboots on c8000.

Signed-off-by: John David Anglin  <dave.anglin@bell.net>
Cc: <stable@vger.kernel.org> # v3.18+
Signed-off-by: Helge Deller <deller@gmx.de>
 		2016-11-25 12:31:57 +01:00
..
.gitignore parisc: add arch/parisc/kernel/.gitignore 2008-10-10 16:32:28 +00:00
Makefile parisc: Fix ftrace function tracer 2016-04-14 17:47:19 +02:00
asm-offsets.c parisc: Unbreak handling exceptions from kernel modules 2016-04-08 22:14:14 +02:00
audit.c parisc: add kernel audit feature 2013-11-07 22:27:20 +01:00
binfmt_elf32.c parisc: fix redefinition of SET_PERSONALITY 2013-03-02 20:15:28 +01:00
cache.c parisc: Fix races in parisc_setup_cache_timing() 2016-11-25 12:31:57 +01:00
compat_audit.c parisc: add kernel audit feature 2013-11-07 22:27:20 +01:00
drivers.c parisc: use KERN_CONT when printing device inventory 2016-11-02 23:04:46 +01:00
entry.S parisc: Add cfi_startproc and cfi_endproc to assembly code 2016-10-05 22:54:40 +02:00
firmware.c parisc: Add break statements to pdc_pat_io_pci_cfg_read() 2016-08-02 16:44:33 +02:00
ftrace.c ftrace: Add return address pointer to ftrace_ret_stack 2016-08-24 12:15:14 +02:00
hardware.c parisc: add serial ports of C8000/1GHz machine to hardware database 2014-07-13 15:51:58 +02:00
head.S parisc: Fix ftrace function tracer 2016-04-14 17:47:19 +02:00
hpmc.S parisc: Add cfi_startproc and cfi_endproc to assembly code 2016-10-05 22:54:40 +02:00
inventory.c parisc: Fix printk continuations in system detection 2016-11-22 18:09:33 +01:00
irq.c parisc: Filter out spurious interrupts in PA-RISC irq handler 2015-09-08 15:31:16 +02:00
module.c parisc: Handle R_PARISC_PCREL32 relocations in kernel modules 2016-04-08 22:10:35 +02:00
pa7300lc.c
…
pacache.S parisc: Add cfi_startproc and cfi_endproc to assembly code 2016-10-05 22:54:40 +02:00
parisc_ksyms.c parisc: Avoid function pointers for kernel exception routines 2016-04-08 22:13:45 +02:00
pci-dma.c dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
pci.c parisc: Initialize PCI bridge cache line and default latency 2016-01-12 22:03:21 +01:00
pdc_chassis.c parisc: single_open() leaks 2013-05-05 00:10:41 -04:00
pdc_cons.c parisc: don't use module_init for non-modular core pdc_cons code 2015-06-16 14:12:30 -04:00
perf.c parisc64: don't use module_init for non-modular core perf code 2015-06-16 14:12:30 -04:00
perf_asm.S Revert "parisc: fix trivial section name warnings" 2008-06-13 10:49:45 -04:00
perf_images.h
…
process.c exit_thread: remove empty bodies 2016-05-20 17:58:30 -07:00
processor.c parisc: Fix automatic selection of cr16 clocksource 2016-08-20 13:33:51 +02:00
ptrace.c parisc/ptrace: run seccomp after ptrace 2016-06-14 10:54:44 -07:00
real2.S parisc: Add cfi_startproc and cfi_endproc to assembly code 2016-10-05 22:54:40 +02:00
setup.c parisc: Fix races in parisc_setup_cache_timing() 2016-11-25 12:31:57 +01:00
signal.c parisc: Fix syscall restarts 2015-12-21 10:16:18 +01:00
signal32.c parisc: Fix SIGSYS signals in compat case 2016-03-31 12:28:37 +02:00
signal32.h constify copy_siginfo_to_user{,32}() 2013-11-09 00:16:29 -05:00
smp.c parisc: Check return value of smp_boot_one_cpu() 2016-09-20 18:02:36 +02:00
stacktrace.c parisc: add LATENCYTOP_SUPPORT and CONFIG_STACKTRACE_SUPPORT 2009-03-31 02:51:34 +00:00
sys_parisc.c parisc: Drop alloc_hugepages and free_hugepages syscalls 2016-03-23 15:42:18 +01:00
sys_parisc32.c parisc: drop unused defines and header includes 2014-07-13 15:56:12 +02:00
syscall.S parisc: Use LINUX_GATEWAY_ADDR define instead of hardcoded value 2016-11-02 23:06:38 +01:00
syscall_table.S parisc: Wire up preadv2 and pwritev2 syscalls 2016-03-23 16:22:42 +01:00
time.c parisc: Fix self-detected CPU stall warnings on Mako machines 2016-09-25 21:27:01 +02:00
topology.c parisc: Replace NR_CPUS in parisc code 2009-01-05 19:09:02 +00:00
traps.c parisc: Show trap name in kernel crash 2016-10-11 20:52:47 +02:00
unaligned.c parisc: Move die_if_kernel() prototype into traps.h header 2016-06-05 08:49:01 +02:00
unwind.c parisc: Fix backtrace on PA-RISC 2016-06-04 22:05:07 +02:00
vmlinux.lds.S parisc: Move exception table into read-only section 2016-10-09 13:29:07 +02:00