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| author | Andy Lutomirski <luto@kernel.org> | 2021-11-05 21:20:47 -0700 |
|---|---|---|
| committer | Andy Lutomirski <luto@kernel.org> | 2021-11-05 21:20:47 -0700 |
| commit | 54b675d9b28d9a56289d06a813250472bc621f40 (patch) | |
| tree | d3f2f68e1f83399edb2df20b788d23c84233ae55 | |
| parent | 0304e8588dd4cf6d73a7553b9913e80758f3f399 (diff) | |
| download | linux-sched/bad_lazymm.tar.gz | |
[HACK] demonstrate lazy tlb issuessched/bad_lazymm
| -rw-r--r-- | arch/Kconfig | 1 | ||||
| -rw-r--r-- | kernel/sched/core.c | 7 |
2 files changed, 8 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index cca27f1b5d0edb..19f273642d8fa6 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -442,6 +442,7 @@ config ARCH_WANT_IRQS_OFF_ACTIVATE_MM config MMU_LAZY_TLB_REFCOUNT def_bool y depends on !MMU_LAZY_TLB_SHOOTDOWN + depends on !X86 # This option allows MMU_LAZY_TLB_REFCOUNT=n. It ensures no CPUs are using an # mm as a lazy tlb beyond its last reference count, by shooting down these diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 25dd795497e818..c5a0c1e92524cf 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4903,6 +4903,13 @@ context_switch(struct rq *rq, struct task_struct *prev, arch_start_context_switch(prev); /* + * Sanity check: if something went wrong and the previous mm was + * freed while we were still using it, KASAN might not notice + * without help. + */ + kasan_check_byte(prev->active_mm); + + /* * kernel -> kernel lazy + transfer active * user -> kernel lazy + mmgrab_lazy_tlb() active * |