| Message ID | 20200407051636.648369-12-npiggin@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | powerpc/64: machine check and system reset fixes | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (2c0ce4ff35994a7b12cc9879ced52c9e7c2e6667) |
| snowpatch_ozlabs/checkpatch | warning | total: 0 errors, 2 warnings, 0 checks, 57 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
Le 07/04/2020 à 07:16, Nicholas Piggin a écrit : > machine_check_early is taken as an NMI, so nmi_enter is used there. > machine_check_exception is no longer taken as an NMI (it's invoked > via irq_work in the case a machine check hits in kernel mode), so > remove the nmi_enter from that case. Euh ... Is that also the case for PPC32 ? AFAIK machine_check_exception() is called as an NMI on PPC32. Christophe > > In NMI context, hash faults don't try to refill the hash table, which > can lead to crashes accessing non-pinned kernel pages. System reset > still has this potential problem. > > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > --- > arch/powerpc/kernel/mce.c | 7 +++++++ > arch/powerpc/kernel/process.c | 2 +- > arch/powerpc/kernel/traps.c | 13 +------------ > 3 files changed, 9 insertions(+), 13 deletions(-) > > diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c > index 8077b5fb18a7..be7e3f92a7b5 100644 > --- a/arch/powerpc/kernel/mce.c > +++ b/arch/powerpc/kernel/mce.c > @@ -574,6 +574,9 @@ EXPORT_SYMBOL_GPL(machine_check_print_event_info); > long machine_check_early(struct pt_regs *regs) > { > long handled = 0; > + bool nested = in_nmi(); > + if (!nested) > + nmi_enter(); > > hv_nmi_check_nonrecoverable(regs); > > @@ -582,6 +585,10 @@ long machine_check_early(struct pt_regs *regs) > */ > if (ppc_md.machine_check_early) > handled = ppc_md.machine_check_early(regs); > + > + if (!nested) > + nmi_exit(); > + > return handled; > } > > diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c > index 9c21288f8645..44410dd3029f 100644 > --- a/arch/powerpc/kernel/process.c > +++ b/arch/powerpc/kernel/process.c > @@ -1421,7 +1421,7 @@ void show_regs(struct pt_regs * regs) > pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr); > #endif > #ifdef CONFIG_PPC64 > - pr_cont("IRQMASK: %lx ", regs->softe); > + pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce); > #endif > #ifdef CONFIG_PPC_TRANSACTIONAL_MEM > if (MSR_TM_ACTIVE(regs->msr)) > diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c > index 3fca22276bb1..9f221772eb73 100644 > --- a/arch/powerpc/kernel/traps.c > +++ b/arch/powerpc/kernel/traps.c > @@ -823,9 +823,6 @@ int machine_check_generic(struct pt_regs *regs) > void machine_check_exception(struct pt_regs *regs) > { > int recover = 0; > - bool nested = in_nmi(); > - if (!nested) > - nmi_enter(); > > __this_cpu_inc(irq_stat.mce_exceptions); > > @@ -851,20 +848,12 @@ void machine_check_exception(struct pt_regs *regs) > if (check_io_access(regs)) > goto bail; > > - if (!nested) > - nmi_exit(); > - > die("Machine check", regs, SIGBUS); > > +bail: > /* Must die if the interrupt is not recoverable */ > if (!(regs->msr & MSR_RI)) > nmi_panic(regs, "Unrecoverable Machine check"); > - > - return; > - > -bail: > - if (!nested) > - nmi_exit(); > } > > void SMIException(struct pt_regs *regs) >
Hi Nicholas,
I love your patch! Yet something to improve:
[auto build test ERROR on powerpc/next]
[also build test ERROR on next-20200412]
[cannot apply to tip/perf/core v5.6]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Nicholas-Piggin/powerpc-64-machine-check-and-system-reset-fixes/20200407-134803
base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-randconfig-a001-20200412 (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 9.3.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=9.3.0 make.cross ARCH=powerpc
If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
In file included from include/linux/kernel.h:15,
from include/asm-generic/bug.h:19,
from arch/powerpc/include/asm/bug.h:109,
from include/linux/bug.h:5,
from arch/powerpc/include/asm/mmu.h:130,
from arch/powerpc/include/asm/paca.h:18,
from arch/powerpc/include/asm/current.h:13,
from include/linux/sched.h:12,
from arch/powerpc/kernel/process.c:14:
arch/powerpc/kernel/process.c: In function 'show_regs':
>> arch/powerpc/kernel/process.c:1424:74: error: 'struct paca_struct' has no member named 'in_nmi'
1424 | pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
| ^~
include/linux/printk.h:317:26: note: in definition of macro 'pr_cont'
317 | printk(KERN_CONT fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~
>> arch/powerpc/kernel/process.c:1424:99: error: 'struct paca_struct' has no member named 'in_mce'
1424 | pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
| ^~
include/linux/printk.h:317:26: note: in definition of macro 'pr_cont'
317 | printk(KERN_CONT fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~
vim +1424 arch/powerpc/kernel/process.c
1400
1401 void show_regs(struct pt_regs * regs)
1402 {
1403 int i, trap;
1404
1405 show_regs_print_info(KERN_DEFAULT);
1406
1407 printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
1408 regs->nip, regs->link, regs->ctr);
1409 printk("REGS: %px TRAP: %04lx %s (%s)\n",
1410 regs, regs->trap, print_tainted(), init_utsname()->release);
1411 printk("MSR: "REG" ", regs->msr);
1412 print_msr_bits(regs->msr);
1413 pr_cont(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer);
1414 trap = TRAP(regs);
1415 if ((TRAP(regs) != 0xc00) && cpu_has_feature(CPU_FTR_CFAR))
1416 pr_cont("CFAR: "REG" ", regs->orig_gpr3);
1417 if (trap == 0x200 || trap == 0x300 || trap == 0x600)
1418 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
1419 pr_cont("DEAR: "REG" ESR: "REG" ", regs->dar, regs->dsisr);
1420 #else
1421 pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr);
1422 #endif
1423 #ifdef CONFIG_PPC64
> 1424 pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
1425 #endif
1426 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1427 if (MSR_TM_ACTIVE(regs->msr))
1428 pr_cont("\nPACATMSCRATCH: %016llx ", get_paca()->tm_scratch);
1429 #endif
1430
1431 for (i = 0; i < 32; i++) {
1432 if ((i % REGS_PER_LINE) == 0)
1433 pr_cont("\nGPR%02d: ", i);
1434 pr_cont(REG " ", regs->gpr[i]);
1435 if (i == LAST_VOLATILE && !FULL_REGS(regs))
1436 break;
1437 }
1438 pr_cont("\n");
1439 #ifdef CONFIG_KALLSYMS
1440 /*
1441 * Lookup NIP late so we have the best change of getting the
1442 * above info out without failing
1443 */
1444 printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
1445 printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
1446 #endif
1447 show_stack(current, (unsigned long *) regs->gpr[1]);
1448 if (!user_mode(regs))
1449 show_instructions(regs);
1450 }
1451
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Excerpts from Christophe Leroy's message of April 7, 2020 3:37 pm: > > > Le 07/04/2020 à 07:16, Nicholas Piggin a écrit : >> machine_check_early is taken as an NMI, so nmi_enter is used there. >> machine_check_exception is no longer taken as an NMI (it's invoked >> via irq_work in the case a machine check hits in kernel mode), so >> remove the nmi_enter from that case. > > Euh ... Is that also the case for PPC32 ? > > AFAIK machine_check_exception() is called as an NMI on PPC32. Sorry I missed your comment. You're right, I'll make this change depend on 64S. Thanks for reviewing them. Thanks, Nick
diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c index 8077b5fb18a7..be7e3f92a7b5 100644 --- a/arch/powerpc/kernel/mce.c +++ b/arch/powerpc/kernel/mce.c @@ -574,6 +574,9 @@ EXPORT_SYMBOL_GPL(machine_check_print_event_info); long machine_check_early(struct pt_regs *regs) { long handled = 0; + bool nested = in_nmi(); + if (!nested) + nmi_enter(); hv_nmi_check_nonrecoverable(regs); @@ -582,6 +585,10 @@ long machine_check_early(struct pt_regs *regs) */ if (ppc_md.machine_check_early) handled = ppc_md.machine_check_early(regs); + + if (!nested) + nmi_exit(); + return handled; } diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 9c21288f8645..44410dd3029f 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1421,7 +1421,7 @@ void show_regs(struct pt_regs * regs) pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr); #endif #ifdef CONFIG_PPC64 - pr_cont("IRQMASK: %lx ", regs->softe); + pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce); #endif #ifdef CONFIG_PPC_TRANSACTIONAL_MEM if (MSR_TM_ACTIVE(regs->msr)) diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 3fca22276bb1..9f221772eb73 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -823,9 +823,6 @@ int machine_check_generic(struct pt_regs *regs) void machine_check_exception(struct pt_regs *regs) { int recover = 0; - bool nested = in_nmi(); - if (!nested) - nmi_enter(); __this_cpu_inc(irq_stat.mce_exceptions); @@ -851,20 +848,12 @@ void machine_check_exception(struct pt_regs *regs) if (check_io_access(regs)) goto bail; - if (!nested) - nmi_exit(); - die("Machine check", regs, SIGBUS); +bail: /* Must die if the interrupt is not recoverable */ if (!(regs->msr & MSR_RI)) nmi_panic(regs, "Unrecoverable Machine check"); - - return; - -bail: - if (!nested) - nmi_exit(); } void SMIException(struct pt_regs *regs)
machine_check_early is taken as an NMI, so nmi_enter is used there. machine_check_exception is no longer taken as an NMI (it's invoked via irq_work in the case a machine check hits in kernel mode), so remove the nmi_enter from that case. In NMI context, hash faults don't try to refill the hash table, which can lead to crashes accessing non-pinned kernel pages. System reset still has this potential problem. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/kernel/mce.c | 7 +++++++ arch/powerpc/kernel/process.c | 2 +- arch/powerpc/kernel/traps.c | 13 +------------ 3 files changed, 9 insertions(+), 13 deletions(-)