Messages in this thread Patch in this message | | | From | guoren@kernel ... | Subject | [PATCH 3/3] riscv/signal: Fixup additional syscall restarting | Date | Tue, 2 Apr 2019 16:02:33 +0800 |
| |
From: Guo Ren <ren_guo@c-sky.com>
The function of do_notify_resume called by entry.S could be entered in loop when SIGPENDING was setted again before sret. So we must add prevent code to make syscall restart (regs->sepc -= 0x4) or it may re-execute unexpected instructions.
Just like in_syscall & forget_syscall used by arm.
Signed-off-by: Guo Ren <ren_guo@c-sky.com> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Arnd Bergmann <arnd@arndb.de> --- arch/riscv/kernel/signal.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 837e164..804d6ee 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -234,6 +234,9 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) /* Are we from a system call? */ if (regs->scause == EXC_SYSCALL) { + /* Avoid additional syscall restarting via ret_from_exception */ + regs->scause = -1UL; + /* If so, check system call restarting.. */ switch (regs->a0) { case -ERESTART_RESTARTBLOCK: @@ -272,6 +275,9 @@ static void do_signal(struct pt_regs *regs) /* Did we come from a system call? */ if (regs->scause == EXC_SYSCALL) { + /* Avoid additional syscall restarting via ret_from_exception */ + regs->scause = -1UL; + /* Restart the system call - no handlers present */ switch (regs->a0) { case -ERESTARTNOHAND: -- 2.7.4
| |