diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2023-06-07 10:56:00 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-06-09 16:35:52 +1000 |
| commit | dfaed3e1fa7099de8de4e89cbe7eb9c1bca27dfe (patch) | |
| tree | 44c4ba84a5a96e18e424ea3dbbcd8e45d64729f0 | |
| parent | 719dfd5925e186e09a2a6f23016936ac436f3d78 (diff) | |
powerpc/64s/radix: Fix exit lazy tlb mm switch with irqs enabled
Switching mm and tinkering with current->active_mm should be done with
irqs disabled. There is a path where exit_lazy_flush_tlb can be called
with irqs enabled:
exit_lazy_flush_tlb
flush_type_needed
__flush_all_mm
tlb_finish_mmu
exit_mmap
Which results in the switching being done with irqs enabled, which is
incorrect.
Fixes: a665eec0a22e ("powerpc/64s/radix: Fix mm_cpumask trimming race vs kthread_use_mm")
Cc: stable@vger.kernel.org # v5.10+
Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Link: https://lore.kernel.org/linuxppc-dev/A9A5D83D-BA70-47A4-BCB4-30C1AE19BC22@linux.ibm.com/
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230607005601.583293-1-npiggin@gmail.com
| -rw-r--r-- | arch/powerpc/mm/book3s64/radix_tlb.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c index ce804b7bf84e..0bd4866d9824 100644 --- a/arch/powerpc/mm/book3s64/radix_tlb.c +++ b/arch/powerpc/mm/book3s64/radix_tlb.c @@ -795,12 +795,20 @@ void exit_lazy_flush_tlb(struct mm_struct *mm, bool always_flush) goto out; if (current->active_mm == mm) { + unsigned long flags; + WARN_ON_ONCE(current->mm != NULL); - /* Is a kernel thread and is using mm as the lazy tlb */ + /* + * It is a kernel thread and is using mm as the lazy tlb, so + * switch it to init_mm. This is not always called from IPI + * (e.g., flush_type_needed), so must disable irqs. + */ + local_irq_save(flags); mmgrab_lazy_tlb(&init_mm); current->active_mm = &init_mm; switch_mm_irqs_off(mm, &init_mm, current); mmdrop_lazy_tlb(mm); + local_irq_restore(flags); } /* |