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Message-ID: <20150811141827.GJ2521@kernel.org>
Date:	Tue, 11 Aug 2015 11:18:27 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc:	David Ahern <dsahern@...il.com>, Jiri Olsa <jolsa@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: perf probe -L sys_select or sys_poll

Hi Masami,

	Have you noticed that sys_select or sys_poll stops after the
first few lines? Please let me know if you need more info than is below.

  [root@zoo ~]# perf probe -L sys_select
  <SyS_select@...me/git/linux/fs/select.c:0>
      0  SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
                        fd_set __user *, exp, struct timeval __user *, tvp)
         {
                struct timespec end_time, *to = NULL;

  [root@zoo ~]# perf probe -L sys_poll
  <SyS_poll@...me/git/linux/fs/select.c:0>
      0  SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
                        int, timeout_msecs)
         {
                struct timespec end_time, *to = NULL;

  [root@zoo ~]#

I haven't investigated it too much, if there is some trouble that makes
'perf probe -L' to stop like that maybe we should warn the user somehow?

Using -v didn't helped that much:

  [root@zoo ~]# perf probe -v -L sys_poll
  Using /root/.debug/.build-id/a8/26726b5ddacfab1f0bade868f1a7924f6b20c4 for symbols
  Open Debuginfo file: /root/.debug/.build-id/a8/26726b5ddacfab1f0bade868f1a7924f6b20c4
  path: (null)
  Symbol sys_poll address found : ffffffff812297e0
  fname: /home/git/linux/fs/select.c, lineno:957
  New line range: 957 to 2147483647
  path: /home/git/linux/fs/select.c
  <SyS_poll@...me/git/linux/fs/select.c:0>
      0  SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
                        int, timeout_msecs)
         {
                struct timespec end_time, *to = NULL;

  [root@zoo ~]#

  [acme@zoo linux]$ cat /etc/fedora-release 
  Fedora release 21 (Twenty One)
  [acme@zoo linux]$ rpm -q elfutils
  elfutils-0.163-1.fc21.x86_64
  [acme@zoo linux]$ 

  [acme@zoo linux]$ uname -a
  Linux zoo 4.2.0-rc5+ #1 SMP Tue Aug 4 16:55:11 BRT 2015 x86_64 x86_64 x86_64 GNU/Linux

  objdump --start-address=0xffffffff812297e0 -dS /root/.debug/.build-id/a8/26726b5ddacfab1f0bade868f1a7924f6b20c4 | less
  /root/.debug/.build-id/a8/26726b5ddacfab1f0bade868f1a7924f6b20c4:     file format elf64-x86-64


  Disassembly of section .text:

  ffffffff812297e0 <SyS_poll>:
		ret = -ERESTART_RESTARTBLOCK;
	}
	return ret;
  }

  SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
  ffffffff812297e0:	e8 4b af 53 00       	callq  ffffffff81764730 <__fentry__>
  ffffffff812297e5:	55                   	push   %rbp
  ffffffff812297e6:	48 89 d1             	mov    %rdx,%rcx
  ffffffff812297e9:	48 89 e5             	mov    %rsp,%rbp
  ffffffff812297ec:	41 54                	push   %r12
  ffffffff812297ee:	53                   	push   %rbx
  ffffffff812297ef:	49 89 fc             	mov    %rdi,%r12
  ffffffff812297f2:	48 89 f3             	mov    %rsi,%rbx
  ffffffff812297f5:	48 83 ec 20          	sub    $0x20,%rsp
  ffffffff812297f9:	65 48 8b 04 25 28 00 	mov    %gs:0x28,%rax
  ffffffff81229800:	00 00 
  ffffffff81229802:	48 89 45 e8          	mov    %rax,-0x18(%rbp)
  ffffffff81229806:	31 c0                	xor    %eax,%eax
		  int, timeout_msecs)
  {
	  struct timespec end_time, *to = NULL;
	  int ret;
  
	  if (timeout_msecs >= 0) {
  ffffffff81229808:	85 d2                	test   %edx,%edx
  ffffffff8122980a:	78 64                	js     ffffffff81229870 <SyS_poll+0x90>
		  to = &end_time;
		  poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
			  NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
  ffffffff8122980c:	89 c8                	mov    %ecx,%eax
  ffffffff8122980e:	ba d3 4d 62 10       	mov    $0x10624dd3,%edx
	  struct timespec end_time, *to = NULL;
	  int ret;
  
	  if (timeout_msecs >= 0) {
		  to = &end_time;
		  poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
  ffffffff81229813:	48 8d 7d d8          	lea    -0x28(%rbp),%rdi
			  NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
  ffffffff81229817:	f7 ea                	imul   %edx
  ffffffff81229819:	89 c8                	mov    %ecx,%eax
  ffffffff8122981b:	c1 f8 1f             	sar    $0x1f,%eax
  ffffffff8122981e:	c1 fa 06             	sar    $0x6,%edx
  ffffffff81229821:	89 d6                	mov    %edx,%esi
  ffffffff81229823:	29 c6                	sub    %eax,%esi
  ffffffff81229825:	69 c6 e8 03 00 00    	imul   $0x3e8,%esi,%eax
	  struct timespec end_time, *to = NULL;
	  int ret;
  
	  if (timeout_msecs >= 0) {
		  to = &end_time;
		  poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
  ffffffff8122982b:	48 63 f6             	movslq %esi,%rsi
			  NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
  ffffffff8122982e:	29 c1                	sub    %eax,%ecx
  ffffffff81229830:	48 63 c9             	movslq %ecx,%rcx
	  struct timespec end_time, *to = NULL;
	  int ret;
  
	  if (timeout_msecs >= 0) {
		  to = &end_time;
		  poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
  ffffffff81229833:	48 69 d1 40 42 0f 00 	imul   $0xf4240,%rcx,%rdx
  ffffffff8122983a:	e8 21 eb ff ff       	callq  ffffffff81228360 <poll_select_set_timeout>
			  NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
	  }
  
	  ret = do_sys_poll(ufds, nfds, to);
  ffffffff8122983f:	48 8d 55 d8          	lea    -0x28(%rbp),%rdx
  ffffffff81229843:	89 de                	mov    %ebx,%esi
  ffffffff81229845:	4c 89 e7             	mov    %r12,%rdi
  ffffffff81229848:	e8 73 f9 ff ff       	callq  ffffffff812291c0 <do_sys_poll>
  
	  if (ret == -EINTR) {
  ffffffff8122984d:	83 f8 fc             	cmp    $0xfffffffc,%eax
  ffffffff81229850:	74 5c                	je     ffffffff812298ae <SyS_poll+0xce>
		  ret = -ERESTART_RESTARTBLOCK;
	  }
	  return ret;
  }
  
  SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
  ffffffff81229852:	48 8b 5d e8          	mov    -0x18(%rbp),%rbx
  ffffffff81229856:	65 48 33 1c 25 28 00 	xor    %gs:0x28,%rbx
  ffffffff8122985d:	00 00 
		  } else
			  restart_block->poll.has_timeout = 0;
  
		  ret = -ERESTART_RESTARTBLOCK;
	  }
	  return ret;
ffffffff8122985f:	48 98                	cltq   
		ret = -ERESTART_RESTARTBLOCK;
	}
	return ret;
}

  SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
  ffffffff81229861:	0f 85 92 00 00 00    	jne    ffffffff812298f9 <SyS_poll+0x119>
  ffffffff81229867:	48 83 c4 20          	add    $0x20,%rsp
  ffffffff8122986b:	5b                   	pop    %rbx
  ffffffff8122986c:	41 5c                	pop    %r12
  ffffffff8122986e:	5d                   	pop    %rbp
  ffffffff8122986f:	c3                   	retq   
		  to = &end_time;
		  poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
			  NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
	  }
  
	  ret = do_sys_poll(ufds, nfds, to);
  ffffffff81229870:	31 d2                	xor    %edx,%edx
  ffffffff81229872:	e8 49 f9 ff ff       	callq  ffffffff812291c0 <do_sys_poll>
  
	  if (ret == -EINTR) {
  ffffffff81229877:	83 f8 fc             	cmp    $0xfffffffc,%eax
  ffffffff8122987a:	75 d6                	jne    ffffffff81229852 <SyS_poll+0x72>
  
  DECLARE_PER_CPU(struct task_struct *, current_task);
  
  static __always_inline struct task_struct *get_current(void)
  {
	  return this_cpu_read_stable(current_task);
  ffffffff8122987c:	65 48 8b 04 25 40 b9 	mov    %gs:0xb940,%rax
  ffffffff81229883:	00 00 
		  struct restart_block *restart_block;
  
		  restart_block = &current->restart_block;
		  restart_block->fn = do_restart_poll;
  ffffffff81229885:	48 c7 80 58 03 00 00 	movq   $0xffffffff81229760,0x358(%rax)
  ffffffff8122988c:	60 97 22 81 
		  restart_block->poll.ufds = ufds;
  ffffffff81229890:	4c 89 a0 60 03 00 00 	mov    %r12,0x360(%rax)
		  restart_block->poll.nfds = nfds;
  ffffffff81229897:	89 98 68 03 00 00    	mov    %ebx,0x368(%rax)
		  if (timeout_msecs >= 0) {
			  restart_block->poll.tv_sec = end_time.tv_sec;
			  restart_block->poll.tv_nsec = end_time.tv_nsec;
			  restart_block->poll.has_timeout = 1;
		  } else
			  restart_block->poll.has_timeout = 0;
  ffffffff8122989d:	c7 80 6c 03 00 00 00 	movl   $0x0,0x36c(%rax)
  ffffffff812298a4:	00 00 00 
  
		  ret = -ERESTART_RESTARTBLOCK;
  ffffffff812298a7:	b8 fc fd ff ff       	mov    $0xfffffdfc,%eax
  ffffffff812298ac:	eb a4                	jmp    ffffffff81229852 <SyS_poll+0x72>
		  restart_block->fn = do_restart_poll;
		  restart_block->poll.ufds = ufds;
		  restart_block->poll.nfds = nfds;
  
		  if (timeout_msecs >= 0) {
			  restart_block->poll.tv_sec = end_time.tv_sec;
  ffffffff812298ae:	48 8b 55 d8          	mov    -0x28(%rbp),%rdx
  ffffffff812298b2:	65 48 8b 04 25 40 b9 	mov    %gs:0xb940,%rax
  ffffffff812298b9:	00 00 
  
	  if (ret == -EINTR) {
		  struct restart_block *restart_block;
  
		  restart_block = &current->restart_block;
		  restart_block->fn = do_restart_poll;
  ffffffff812298bb:	48 c7 80 58 03 00 00 	movq   $0xffffffff81229760,0x358(%rax)
  ffffffff812298c2:	60 97 22 81 
		  restart_block->poll.ufds = ufds;
  ffffffff812298c6:	4c 89 a0 60 03 00 00 	mov    %r12,0x360(%rax)
		  restart_block->poll.nfds = nfds;
  
		  if (timeout_msecs >= 0) {
			  restart_block->poll.tv_sec = end_time.tv_sec;
  ffffffff812298cd:	48 89 90 70 03 00 00 	mov    %rdx,0x370(%rax)
			  restart_block->poll.tv_nsec = end_time.tv_nsec;
  ffffffff812298d4:	48 8b 55 e0          	mov    -0x20(%rbp),%rdx
		  struct restart_block *restart_block;
  
		  restart_block = &current->restart_block;
		  restart_block->fn = do_restart_poll;
		  restart_block->poll.ufds = ufds;
		  restart_block->poll.nfds = nfds;
  ffffffff812298d8:	89 98 68 03 00 00    	mov    %ebx,0x368(%rax)
  
		  if (timeout_msecs >= 0) {
			  restart_block->poll.tv_sec = end_time.tv_sec;
			  restart_block->poll.tv_nsec = end_time.tv_nsec;
			  restart_block->poll.has_timeout = 1;
  ffffffff812298de:	c7 80 6c 03 00 00 01 	movl   $0x1,0x36c(%rax)
  ffffffff812298e5:	00 00 00 
		  restart_block->poll.ufds = ufds;
		  restart_block->poll.nfds = nfds;
  
		  if (timeout_msecs >= 0) {
			  restart_block->poll.tv_sec = end_time.tv_sec;
			  restart_block->poll.tv_nsec = end_time.tv_nsec;
  ffffffff812298e8:	48 89 90 78 03 00 00 	mov    %rdx,0x378(%rax)
			  restart_block->poll.has_timeout = 1;
		  } else
			  restart_block->poll.has_timeout = 0;
  
		  ret = -ERESTART_RESTARTBLOCK;
  ffffffff812298ef:	b8 fc fd ff ff       	mov    $0xfffffdfc,%eax
  ffffffff812298f4:	e9 59 ff ff ff       	jmpq   ffffffff81229852 <SyS_poll+0x72>
		  ret = -ERESTART_RESTARTBLOCK;
	  }
	  return ret;
  }
  
  SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
  ffffffff812298f9:	e8 02 0d e7 ff       	callq  ffffffff8109a600 <__stack_chk_fail>
  ffffffff812298fe:	66 90                	xchg   %ax,%ax
  
  ffffffff81229900 <SyS_ppoll>:
		  ret = -ERESTART_RESTARTBLOCK;
	  }
	  return ret;
  }
--
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