perf probe -L sys_select or sys_poll

From: Arnaldo Carvalho de Melo
Date: Tue Aug 11 2015 - 10:18:38 EST

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@/home/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@/home/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@/home/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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