----- Original Message -----
> On 5/30/2019 5:03 PM, Dave Anderson wrote:
> >
> >
> > ----- Original Message -----
> >> Hi Dave,
> >>
> >> I don't know why this difference arises, but with certain kernel
> >> configurations,
> >> the source file and line information of the schedule() function becomes
> >> the
> >> following, not "/kernel/sched/core.c".
> >>
> >> crash> sym schedule
> >> ffffffffab0d3666 (T) schedule
> >> /share/src/linux-5.0.1/./arch/x86/include/asm/current.h: 15
> >
> > Yeah, presumably happens because your kernel doesn't have the ftrace nop
> > compiled
> > into the beginning of each function. When it does, the first address in
> > the
> > schedule function would be in kernel/sched/core.c:
> >
> > crash> sym schedule
> > ffffffffa22b5dc0 (T) schedule
> >
> > /usr/src/debug/kernel-5.2.0-0.rc2.1.elrdy/linux-5.2.0-0.rc2.1.elrdy.x86_64/kernel/sched/core.c:
> > 3503
> > crash> dis -l schedule
> >
> > /usr/src/debug/kernel-5.2.0-0.rc2.1.elrdy/linux-5.2.0-0.rc2.1.elrdy.x86_64/kernel/sched/core.c:
> > 3503
> > 0xffffffffa22b5dc0 <schedule>: nopl 0x0(%rax,%rax,1) [FTRACE NOP]
> >
> > /usr/src/debug/kernel-5.2.0-0.rc2.1.elrdy/linux-5.2.0-0.rc2.1.elrdy.x86_64/./arch/x86/include/asm/current.h:
> > 15
> > 0xffffffffa22b5dc5 <schedule+5>: push %rbx
> > 0xffffffffa22b5dc6 <schedule+6>: mov %gs:0x15f00,%rbx
> >
> > /usr/src/debug/kernel-5.2.0-0.rc2.1.elrdy/linux-5.2.0-0.rc2.1.elrdy.x86_64/kernel/sched/core.c:
> > 3506
> > 0xffffffffa22b5dcf <schedule+15>: mov 0x10(%rbx),%rax
> > 0xffffffffa22b5dd3 <schedule+19>: test %rax,%rax
> > 0xffffffffa22b5dd6 <schedule+22>: je 0xffffffffa22b5de2
> > <schedule+34>
> > ...
>
> Ah, I see. Thanks! I think it is CONFIG_DYNAMIC_FTRACE,
> which the config does not have.
>
> $ grep FTRACE config-5.0.1
> CONFIG_HAVE_KPROBES_ON_FTRACE=y
> CONFIG_HAVE_DYNAMIC_FTRACE=y
> CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS=y
> CONFIG_HAVE_FTRACE_MCOUNT_RECORD=y
> CONFIG_FTRACE=y
> # CONFIG_FTRACE_SYSCALLS is not set
> # CONFIG_FTRACE_STARTUP_TEST is not set
>
> Thanks,
> Kazu
Yeah, it's related to these build options in the top-level Makefile:
ifndef CC_FLAGS_FTRACE
CC_FLAGS_FTRACE := -pg
endif
export CC_FLAGS_FTRACE
ifdef CONFIG_HAVE_FENTRY
CC_USING_FENTRY := $(call cc-option, -mfentry -DCC_USING_FENTRY)
endif
KBUILD_CFLAGS += $(CC_FLAGS_FTRACE) $(CC_USING_FENTRY)
KBUILD_AFLAGS += $(CC_USING_FENTRY)
ifdef CONFIG_DYNAMIC_FTRACE
ifdef CONFIG_HAVE_C_RECORDMCOUNT
BUILD_C_RECORDMCOUNT := y
export BUILD_C_RECORDMCOUNT
endif
endif
Your patch is queued for crash-7.2.7:
https://github.com/crash-utility/crash/commit/fdd022616eb0cf5caf4bf8af78ef87fb1b7ea9a0
Thanks,
Dave
>
> >
> > If ftrace is not enabled, then it would show asm/current.h because the
> > first instruction
> > in schedule() is the evaluation of "current":
> >
> > asmlinkage __visible void __sched schedule(void)
> > {
> > struct task_struct *tsk = current;
> >
> > which is #define'd in asm/current.h:ifdef CONFIG_FUNCTION_TRACER
> >
> > #define get_current() (current_thread_info()->task)
> > #define current get_current()
> >
> > Anyway, I'll take a look and test the patch tomorrow.
> >
> > Thanks,
> > Dave
> >
> >>
> >> This causes the "sys -c" option not to print the information of system
> >> calls,
> >> and makes it very slow.
> >>
> >> crash> sys -c | sh -c 'time cat'
> >> NUM SYSTEM CALL FILE AND LINE NUMBER
> >> 0 __x64_sys_read
> >> 1 __x64_sys_write
> >> 2 __x64_sys_open
> >> ...
> >> 333 __x64_sys_io_pgetevents
> >> 334 __x64_sys_rseq
> >>
> >> real 2m32.669s
> >> user 0m0.002s
> >> sys 0m0.022s
> >>
> >> With this patch, the option can print the information in not too long
> >> time:
> >>
> >> crash> sys -c | sh -c 'time cat'
> >> NUM SYSTEM CALL FILE AND LINE NUMBER
> >> 0 __x64_sys_read ../fs/read_write.c: 588
> >> 1 __x64_sys_write ../fs/read_write.c: 610
> >> 2 __x64_sys_open ../fs/open.c: 1079
> >> ...
> >> 333 __x64_sys_io_pgetevents ../fs/aio.c: 2139
> >> 334 __x64_sys_rseq ../kernel/rseq.c: 308
> >>
> >> real 0m10.905s
> >> user 0m0.000s
> >> sys 0m0.024s
> >>
> >> Also, in dump_sys_call_table(), it looks like there is no need to call
> >> get_build_directory() for each system call, so moving it out of the loop
> >> makes it faster.
> >>
> >> [without moving the get_build_directory()]
> >> real 0m15.862s
> >> user 0m0.003s
> >> sys 0m0.020s
> >>
> >> Signed-off-by: Kazuhito Hagio <[email protected]>
> >> ---
> >> kernel.c | 2 +-
> >> symbols.c | 2 +-
> >> 2 files changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/kernel.c b/kernel.c
> >> index db25f22e4ec6..22909d28cefc 100644
> >> --- a/kernel.c
> >> +++ b/kernel.c
> >> @@ -5679,6 +5679,7 @@ dump_sys_call_table(char *spec, int cnt)
> >>
> >> fprintf(fp, "%s", sys_call_hdr);
> >>
> >> + get_build_directory(buf2);
> >> for (i = 0, sct = sys_call_table; i < NR_syscalls; i++, sct++) {
> >> if (!(scp = value_symbol(*sct))) {
> >> if (confirmed || CRASHDEBUG(1)) {
> >> @@ -5710,7 +5711,6 @@ dump_sys_call_table(char *spec, int cnt)
> >> */
> >> sp = value_search(*sct, NULL);
> >> spn = next_symbol(NULL, sp);
> >> - get_build_directory(buf2);
> >>
> >> for (addr = *sct; sp && spn && (addr < spn->value); addr++) {
> >> BZERO(buf1, BUFSIZE);
> >> diff --git a/symbols.c b/symbols.c
> >> index 863d1f0a8e25..3ce8692fd397 100644
> >> --- a/symbols.c
> >> +++ b/symbols.c
> >> @@ -4296,7 +4296,7 @@ get_build_directory(char *buf)
> >> get_line_number(symbol_value("do_schedule"), buf, FALSE);
> >> else
> >> return NULL;
> >> - if ((p = strstr(buf, "/kernel/")))
> >> + if ((p = strstr(buf, "/kernel/")) || (p = strstr(buf, "/./arch/")))
> >> *p = NULLCHAR;
> >> else
> >> return(NULL);
> >> --
> >> 2.18.1
> >>
> >
> > --
> > Crash-utility mailing list
> > [email protected]
> > https://www.redhat.com/mailman/listinfo/crash-utility
> >
>
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