From: Michael Weiser <michael.weiser@xxxxxx>
commit 1962682d2b2fbe6cfa995a85c53c069fadda473e upstream.
Stop printing a (ratelimited) kernel message for each instance of an
unimplemented syscall being called. Userland making an unimplemented
syscall is not necessarily misbehaviour and to be expected with a
current userland running on an older kernel. Also, the current message
looks scary to users but does not actually indicate a real problem nor
help them narrow down the cause. Just rely on sys_ni_syscall() to return
-ENOSYS.
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Martin Vajnar <martin.vajnar@xxxxxxxxx>
Cc: musl@xxxxxxxxxxxxxxxxxx
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Michael Weiser <michael.weiser@xxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
This was backported to v4.14 and later, but is missing in v4.4 and
before, apparently because of a trivial merge conflict. This is
a manual backport I did after I saw a report about the issue
by Martin Vajnar on the musl mailing list.
---
arch/arm64/kernel/traps.c | 8 --------
1 file changed, 8 deletions(-)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 02710f99c137..a8c0fd0574fa 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -381,14 +381,6 @@ asmlinkage long do_ni_syscall(struct pt_regs *regs)
}
#endif
- if (show_unhandled_signals_ratelimited()) {
- pr_info("%s[%d]: syscall %d\n", current->comm,
- task_pid_nr(current), (int)regs->syscallno);
- dump_instr("", regs);
- if (user_mode(regs))
- __show_regs(regs);
- }
-
return sys_ni_syscall();
}
--
2.29.2
