On a 32-bit fast syscall that fails to read its arguments from user
memory, the kernel currently does syscall exit work but not
syscall entry work. This confuses audit and ptrace. For example:
$ ./tools/testing/selftests/x86/syscall_arg_fault_32
...
strace: pid 264258: entering, ptrace_syscall_info.op == 2
...
This is a minimal fix intended for ease of backporting. A more
complete cleanup is coming.
Cc: stable(a)vger.kernel.org
Fixes: 0b085e68f407 ("x86/entry: Consolidate 32/64 bit syscall entry")
Signed-off-by: Andy Lutomirski <luto(a)kernel.org>
---
arch/x86/entry/common.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 0904f5676e4d..8fdb4cb27efe 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -128,7 +128,8 @@ static noinstr bool __do_fast_syscall_32(struct pt_regs *regs)
regs->ax = -EFAULT;
instrumentation_end();
- syscall_exit_to_user_mode(regs);
+ local_irq_disable();
+ irqentry_exit_to_user_mode(regs);
return false;
}
--
2.29.2
The following commit has been merged into the sched/core branch of tip:
Commit-ID: ce29ddc47b91f97e7f69a0fb7cbb5845f52a9825
Gitweb: https://git.kernel.org/tip/ce29ddc47b91f97e7f69a0fb7cbb5845f52a9825
Author: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com>
AuthorDate: Wed, 17 Feb 2021 11:56:51 -05:00
Committer: Ingo Molnar <mingo(a)kernel.org>
CommitterDate: Sat, 06 Mar 2021 12:40:21 +01:00
sched/membarrier: fix missing local execution of ipi_sync_rq_state()
The function sync_runqueues_membarrier_state() should copy the
membarrier state from the @mm received as parameter to each runqueue
currently running tasks using that mm.
However, the use of smp_call_function_many() skips the current runqueue,
which is unintended. Replace by a call to on_each_cpu_mask().
Fixes: 227a4aadc75b ("sched/membarrier: Fix p->mm->membarrier_state racy load")
Reported-by: Nadav Amit <nadav.amit(a)gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Cc: stable(a)vger.kernel.org # 5.4.x+
Link: https://lore.kernel.org/r/74F1E842-4A84-47BF-B6C2-5407DFDD4A4A@gmail.com
---
kernel/sched/membarrier.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c
index acdae62..b5add64 100644
--- a/kernel/sched/membarrier.c
+++ b/kernel/sched/membarrier.c
@@ -471,9 +471,7 @@ static int sync_runqueues_membarrier_state(struct mm_struct *mm)
}
rcu_read_unlock();
- preempt_disable();
- smp_call_function_many(tmpmask, ipi_sync_rq_state, mm, 1);
- preempt_enable();
+ on_each_cpu_mask(tmpmask, ipi_sync_rq_state, mm, true);
free_cpumask_var(tmpmask);
cpus_read_unlock();