diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2021-11-29 13:06:48 +0000 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2021-12-01 00:06:44 +0100 |
| commit | 342b3808786518ced347f40b59bae68664e20007 (patch) | |
| tree | 606e6ea97e7e8dfdaabee98e6e071d8176d830b7 | |
| parent | 050e22bfc4f450d342dbb7eaea470858ad567bce (diff) | |
arm64: Snapshot thread flags
Some thread flags can be set remotely, and so even when IRQs are disabled,
the flags can change under our feet. Generally this is unlikely to cause a
problem in practice, but it is somewhat unsound, and KCSAN will
legitimately warn that there is a data race.
To avoid such issues, a snapshot of the flags has to be taken prior to
using them. Some places already use READ_ONCE() for that, others do not.
Convert them all to the new flag accessor helpers.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20211129130653.2037928-7-mark.rutland@arm.com
| -rw-r--r-- | arch/arm64/kernel/entry-common.c | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/ptrace.c | 4 | ||||
| -rw-r--r-- | arch/arm64/kernel/signal.c | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/syscall.c | 4 |
4 files changed, 6 insertions, 6 deletions
diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index f7408edf8571..ef7fcefb96bd 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -129,7 +129,7 @@ static __always_inline void prepare_exit_to_user_mode(struct pt_regs *regs) local_daif_mask(); - flags = READ_ONCE(current_thread_info()->flags); + flags = read_thread_flags(); if (unlikely(flags & _TIF_WORK_MASK)) do_notify_resume(regs, flags); } diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 88a9034fb9b5..33cac3d75150 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1839,7 +1839,7 @@ static void tracehook_report_syscall(struct pt_regs *regs, int syscall_trace_enter(struct pt_regs *regs) { - unsigned long flags = READ_ONCE(current_thread_info()->flags); + unsigned long flags = read_thread_flags(); if (flags & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE)) { tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); @@ -1862,7 +1862,7 @@ int syscall_trace_enter(struct pt_regs *regs) void syscall_trace_exit(struct pt_regs *regs) { - unsigned long flags = READ_ONCE(current_thread_info()->flags); + unsigned long flags = read_thread_flags(); audit_syscall_exit(regs); diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 8f6372b44b65..d8aaf4b6f432 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -948,7 +948,7 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags) } local_daif_mask(); - thread_flags = READ_ONCE(current_thread_info()->flags); + thread_flags = read_thread_flags(); } while (thread_flags & _TIF_WORK_MASK); } diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 50a0f1a38e84..c938603b3ba0 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -81,7 +81,7 @@ void syscall_trace_exit(struct pt_regs *regs); static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, const syscall_fn_t syscall_table[]) { - unsigned long flags = current_thread_info()->flags; + unsigned long flags = read_thread_flags(); regs->orig_x0 = regs->regs[0]; regs->syscallno = scno; @@ -148,7 +148,7 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, */ if (!has_syscall_work(flags) && !IS_ENABLED(CONFIG_DEBUG_RSEQ)) { local_daif_mask(); - flags = current_thread_info()->flags; + flags = read_thread_flags(); if (!has_syscall_work(flags) && !(flags & _TIF_SINGLESTEP)) return; local_daif_restore(DAIF_PROCCTX); |