Yu, Fenghua wrote:
>
> >+ if (r13 != sos->prev_IA64_KR_CURRENT) {
> >+ msg = "inconsistent previous current and r13";
> >+ goto no_mod;
> >+ }
> >+
> > if (!mca_recover_range(ms->pmsa_iip)) {
> >- if (r13 != sos->prev_IA64_KR_CURRENT) {
> >- msg = "inconsistent previous current and r13";
> >- goto no_mod;
> >- }
>
> Could you explain whey move the r13 check out of mca_recover_range()?
For my test cases, I can hit cases an MCA without that change (output
below) if the MCA surfaces in the interrupt IVT (address in mca_recover_range()).
The MCA is due to old_bspstore not having a valid virtual address.
--------------------------------------------------------------------------
run test 163
cpu 0, MCA occurred in user space, original stack not modified
Unable to handle kernel paging request at virtual address 603fffffff850048
MCA 4179[0]: Oops 8804682956800 [1]
Modules linked in: errinj
Pid: 0, CPU 1, comm: MCA 4179
psr : 0000101808022030 ifs : 800000000000122c ip : [<a000000100044a10>] Not tainted
ip is at ia64_mca_modify_original_stack+0x1110/0x1240
unat: 0000000000000000 pfs : 000000000000122c rsc : 0000000000000003
rnat: 0000000000000000 bsps: 0000000000000000 pr : 000000560055a9a7
ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c8a70033f
csd : 0000000000000000 ssd : 0000000000000000
b0 : a0000001000449a0 b6 : 4000000000003c40 b7 : a000000000010640
f6 : 000000000000000000000 f7 : 0ffdba200000000000000
f8 : 100018000000000000000 f9 : 10002a000000000000000
f10 : 0fffdccccccccc8c00000 f11 : 1003e0000000000000000
r1 : a000000100f69a00 r2 : 607fffffff84ae58 r3 : 0000000000550281
r8 : 0000000000000000 r9 : 607fffffff84ae40 r10 : 0000000000000000
r11 : 0000000000000000 r12 : e000006007067ac0 r13 : e000006007060000
r14 : 0000000000000001 r15 : e000006007060ce8 r16 : 0000000000000005
r17 : 0000000000000000 r18 : 0000000000000000 r19 : 0000000000000000
r20 : 0000000000000000 r21 : 0000000000000000 r22 : 8000000000000000
r23 : 0000000000000000 r24 : 000000000000003e r25 : 000000000000003f
r26 : 0000000000000009 r27 : 0000000000000000 r28 : 4000000000000000
r29 : 0000000000000000 r30 : 0000000000000000 r31 : c0000000000111c8
Call Trace:
[<a0000001000125e0>] show_stack+0x40/0xa0
sp=e000006007067670 bsp=e000006007061088
[<a000000100012ee0>] show_regs+0x840/0x880
sp=e000006007067840 bsp=e000006007061030
[<a000000100034910>] die+0x250/0x320
sp=e000006007067840 bsp=e000006007060fe0
[<a0000001000592f0>] ia64_do_page_fault+0x930/0xa60
sp=e000006007067860 bsp=e000006007060f90
[<a00000010000b520>] ia64_leave_kernel+0x0/0x290
sp=e0000060070678f0 bsp=e000006007060f90
[<a000000100044a10>] ia64_mca_modify_original_stack+0x1110/0x1240
sp=e000006007067ac0 bsp=e000006007060e30
[<a000000100045ad0>] ia64_mca_handler+0x170/0xb20
sp=e000006007067ad0 bsp=e000006007060dd0
[<a000000100047420>] ia64_os_mca_virtual_begin+0x40/0x140
sp=e000006007067b80 bsp=e000006007060dd0
Kernel panic - not syncing: Attempted to kill the idle task!
--------------------------------------------------------------------------
> >+ for_each_online_cpu(i) {
> >+ if (cpu_isset(i, mca_cpu)) {
> >+ monarch_cpu = i;
> >+ cpu_clear(i, mca_cpu); /* wake next cpu
> */
>
> Just a picky comment...Is it better to changed to
> + if (mca_cpu!=0) {
> + for_each_online_cpu(i) {
> + if (cpu_isset(i, mca_cpu)) {
> + monarch_cpu = i;
> + cpu_clear(i, mca_cpu); /* wake next cpu
> */
>
> it may speed up a bit?. After all in reality, there are few bits set in
> mca_cpu. So there is no need to go through all of online cpus.
That section of code only gets executed if mca_cpu != 0, due to
this line:
if (atomic_dec_return(&mca_count) > 0) {
If mca_count is greater than 0, there is a bit set.
If mca_count == 0, there are no bits set and the code is skipped.
> Thanks.
>
> -Fenghua
>
Thanks,
--
Russ Anderson, OS RAS/Partitioning Project Lead
SGI - Silicon Graphics Inc rja@xxxxxxx
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