From 985faa78687de6e583cfd8b8094d87dcb80c33a6 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 29 Nov 2021 13:06:52 +0000 Subject: powerpc: 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 Signed-off-by: Thomas Gleixner Acked-by: Paul E. McKenney Cc: Benjamin Herrenschmidt Cc: Michael Ellerman Cc: Paul Mackerras Link: https://lore.kernel.org/r/20211129130653.2037928-11-mark.rutland@arm.com --- arch/powerpc/kernel/ptrace/ptrace.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'arch/powerpc/kernel/ptrace/ptrace.c') diff --git a/arch/powerpc/kernel/ptrace/ptrace.c b/arch/powerpc/kernel/ptrace/ptrace.c index 7c7093c17c45..c43f77e2ac31 100644 --- a/arch/powerpc/kernel/ptrace/ptrace.c +++ b/arch/powerpc/kernel/ptrace/ptrace.c @@ -260,8 +260,7 @@ long do_syscall_trace_enter(struct pt_regs *regs) { u32 flags; - flags = READ_ONCE(current_thread_info()->flags) & - (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE); + flags = read_thread_flags() & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE); if (flags) { int rc = tracehook_report_syscall_entry(regs); -- cgit v1.2.3