From: Sven Schnelle svens@linux.ibm.com
[ Upstream commit 00332c16b1604242a56289ff2b26e283dbad0812 ]
tracing expects to see invalid syscalls, so pass it through. The syscall path in entry.S checks the syscall number before looking up the handler, so it is still safe.
Signed-off-by: Sven Schnelle svens@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/kernel/entry.S | 2 +- arch/s390/kernel/ptrace.c | 6 ++---- 2 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index bc85987727f09..c544b7a11ebb3 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -368,9 +368,9 @@ ENTRY(system_call) jnz .Lsysc_nr_ok # svc 0: system call number in %r1 llgfr %r1,%r1 # clear high word in r1 + sth %r1,__PT_INT_CODE+2(%r11) cghi %r1,NR_syscalls jnl .Lsysc_nr_ok - sth %r1,__PT_INT_CODE+2(%r11) slag %r8,%r1,3 .Lsysc_nr_ok: xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index ad71132374f0c..5a2b1501d9983 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -844,11 +844,9 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) * call number to gprs[2]. */ if (test_thread_flag(TIF_SYSCALL_TRACE) && - (tracehook_report_syscall_entry(regs) || - regs->gprs[2] >= NR_syscalls)) { + tracehook_report_syscall_entry(regs)) { /* - * Tracing decided this syscall should not happen or the - * debugger stored an invalid system call number. Skip + * Tracing decided this syscall should not happen. Skip * the system call and the system call restart handling. */ clear_pt_regs_flag(regs, PIF_SYSCALL);