From: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
To: "linux-perf-users@vger.kernel.org"
<linux-perf-users@vger.kernel.org>, Paul Clarke <pc@us.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: sys_exit: NR -1
Date: Wed, 12 Jun 2019 12:02:53 +0530 [thread overview]
Message-ID: <1560320989.8h9se8cb9p.naveen@linux.ibm.com> (raw)
In-Reply-To: <2f004b41-4f6f-3e6f-227a-cb199b8429d2@us.ibm.com>
Paul Clarke wrote:
> What are the circumstances in which raw_syscalls:sys_exit reports "-1" for the syscall ID?
>
> perf 5375 [007] 59632.478528: raw_syscalls:sys_enter: NR 1 (3, 9fb888, 8, 2d83740, 1, 7ffff)
> perf 5375 [007] 59632.478532: raw_syscalls:sys_exit: NR 1 = 8
> perf 5375 [007] 59632.478538: raw_syscalls:sys_enter: NR 15 (11, 7ffffca734b0, 7ffffca73380, 2d83740, 1, 7ffff)
> perf 5375 [007] 59632.478539: raw_syscalls:sys_exit: NR -1 = 8
> perf 5375 [007] 59632.478543: raw_syscalls:sys_enter: NR 16 (4, 2401, 0, 2d83740, 1, 0)
> perf 5375 [007] 59632.478551: raw_syscalls:sys_exit: NR 16 = 0
Which architecture?
For powerpc, see:
static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
{
/*
* Note that we are returning an int here. That means 0xffffffff, ie.
* 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel.
* This is important for seccomp so that compat tasks can set r0 = -1
* to reject the syscall.
*/
return TRAP(regs) == 0xc00 ? regs->gpr[0] : -1;
}
- Naveen
next parent reply other threads:[~2019-06-12 6:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <2f004b41-4f6f-3e6f-227a-cb199b8429d2@us.ibm.com>
2019-06-12 6:32 ` Naveen N. Rao [this message]
2019-06-13 21:00 ` sys_exit: NR -1 Paul Clarke
2019-06-13 21:11 ` Paul Clarke
2019-06-13 21:56 ` sys_exit: NR 0 (was "sys_exit: NR -1") Paul Clarke
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