From: Andy Lutomirski Date: Thu, 4 Mar 2021 19:05:54 +0000 (-0800) Subject: x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls X-Git-Tag: v5.12-rc3~9^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5d5675df792ff67e74a500c4c94db0f99e6a10ef;p=thirdparty%2Fkernel%2Flinux.git x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls 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. Fixes: 0b085e68f407 ("x86/entry: Consolidate 32/64 bit syscall entry") Signed-off-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/8c82296ddf803b91f8d1e5eac89e5803ba54ab0e.1614884673.git.luto@kernel.org --- diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index a2433ae8a65e7..4efd39aacb9f2 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; }