The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 5d5675df792ff67e74a500c4c94db0f99e6a10ef Gitweb: https://git.kernel.org/tip/5d5675df792ff67e74a500c4c94db0f99e6a10ef Author: Andy Lutomirski <luto@xxxxxxxxxx> AuthorDate: Thu, 04 Mar 2021 11:05:54 -08:00 Committer: Borislav Petkov <bp@xxxxxxx> CommitterDate: Sat, 06 Mar 2021 13:10:06 +01:00 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 <luto@xxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/8c82296ddf803b91f8d1e5eac89e5803ba54ab0e.1614884673.git.luto@xxxxxxxxxx --- 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 a2433ae..4efd39a 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; }
