diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2019-09-18 19:31:03 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-09-21 08:36:53 +1000 |
| commit | 7aec584eaf1cc1a527dcbe7d80f2e44e3bfcfe1d (patch) | |
| tree | 7aaa2d7c7f9f5e08c1cee0230630d9711cd4cece /arch/powerpc | |
| parent | a003365cab64b0f7988ac3ccb1da895ce0bece5e (diff) | |
powerpc/book3s64/radix: Remove WARN_ON in destroy_context()
On failed task initialization due to memory allocation failures, we can
call into destroy_context() with process_tb entry already populated.
This patch forces the process_tb entry to zero in destroy_context().
With this patch, we lose the ability to track if we are destroying a
context without flushing the process table entry.
WARNING: CPU: 4 PID: 6368 at arch/powerpc/mm/mmu_context_book3s64.c:246 destroy_context+0x58/0x340
NIP [c0000000000875f8] destroy_context+0x58/0x340
LR [c00000000013da18] __mmdrop+0x78/0x270
Call Trace:
[c000000f7db77c80] [c00000000013da18] __mmdrop+0x78/0x270
[c000000f7db77cf0] [c0000000004d6a34] __do_execve_file.isra.13+0xbd4/0x1000
[c000000f7db77e00] [c0000000004d7428] sys_execve+0x58/0x70
[c000000f7db77e30] [c00000000000b388] system_call+0x5c/0x70
Reported-by: Priya M.A <priyama2@in.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Reformat/tweak comment wording]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190918140103.24395-1-aneesh.kumar@linux.ibm.com
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/mm/book3s64/mmu_context.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/arch/powerpc/mm/book3s64/mmu_context.c b/arch/powerpc/mm/book3s64/mmu_context.c index 2d0cb5ba9a47..0ba30b8b935b 100644 --- a/arch/powerpc/mm/book3s64/mmu_context.c +++ b/arch/powerpc/mm/book3s64/mmu_context.c @@ -256,8 +256,21 @@ void destroy_context(struct mm_struct *mm) #ifdef CONFIG_SPAPR_TCE_IOMMU WARN_ON_ONCE(!list_empty(&mm->context.iommu_group_mem_list)); #endif + /* + * For tasks which were successfully initialized we end up calling + * arch_exit_mmap() which clears the process table entry. And + * arch_exit_mmap() is called before the required fullmm TLB flush + * which does a RIC=2 flush. Hence for an initialized task, we do clear + * any cached process table entries. + * + * The condition below handles the error case during task init. We have + * set the process table entry early and if we fail a task + * initialization, we need to ensure the process table entry is zeroed. + * We need not worry about process table entry caches because the task + * never ran with the PID value. + */ if (radix_enabled()) - WARN_ON(process_tb[mm->context.id].prtb0 != 0); + process_tb[mm->context.id].prtb0 = 0; else subpage_prot_free(mm); destroy_contexts(&mm->context); |