8:57 a.m.
These are update patches to have crash extract the trace_bprintk()
formats from a kernel core dump. It handles the current format
and a new format that I'll be pushing out after the merge window
has closed for Linux 2.6.40. The new format is required for the
kernel debugfs to export the same bprintk data as well.
This means that crash will be able to extract more information than
trace-cmd itself can on a running kernel :)
v2:
o Removed unused 'len' variable.
o Moved count == 0 fix into patch 2
-- Steve
8:57 a.m.
New subject: [PATCH 1/3 v2] crash-trace-command: Fix help for trace extension
The help on trace shows that -s is not implemented.
As it is implemented, change the help message not to say it
isn't.
Signed-off-by: Steven Rostedt <rostedt(a)goodmis.org>
Index: crash-5.1.3/extensions/trace.c
===================================================================
--- crash-5.1.3.orig/extensions/trace.c
+++ crash-5.1.3/extensions/trace.c
@@ -2969,7 +2969,7 @@ static char *help_ftrace[] = {
" by other tracing tools. The dirs and files are generated",
" the same as debugfs/tracing.",
" -m: also dump metadata of ftrace.",
-" -s: also dump symbols of the kernel <not implemented>.",
+" -s: also dump symbols of the kernel.",
"trace dump -t [output-file-name]",
" dump ring_buffers and all meta data to a file that can",
" be parsed by trace-cmd. Default output file name is
\"trace.dat\".",
8:57 a.m.
New subject: [PATCH 2/3 v2] crash-trace-command: Include trace_printk() formats for modules
If a module has a trace_printk() and it is optimized to be a
trace_bprintk() then we want to save the format for that as well.
The trace_bprintk() just saves the pointer of the format in the
ftrace ring buffer, thus trace-cmd requires the mapping of that
address to the format.
Signed-off-by: Steven Rostedt <rostedt(a)goodmis.org>
Index: crash-5.1.3/extensions/trace.c
===================================================================
--- crash-5.1.3.orig/extensions/trace.c
+++ crash-5.1.3/extensions/trace.c
@@ -3341,11 +3341,46 @@ static int save_proc_kallsyms(int fd)
return tmp_file_flush(fd);
}
+static int add_print_address(long address)
+{
+ char string[4096];
+ size_t len;
+ int i;
+
+ len = read_string(address, string, sizeof(string));
+ if (!len)
+ return -1;
+
+ tmp_fprintf("0x%lx : \"", address);
+
+ for (i = 0; string[i]; i++) {
+ switch (string[i]) {
+ case '\n':
+ tmp_fprintf("\\n");
+ break;
+ case '\t':
+ tmp_fprintf("\\t");
+ break;
+ case '\\':
+ tmp_fprintf("\\\\");
+ break;
+ case '"':
+ tmp_fprintf("\\\"");
+ break;
+ default:
+ tmp_fprintf("%c", string[i]);
+ }
+ }
+ tmp_fprintf("\"\n");
+
+ return 0;
+}
+
static int save_ftrace_printk(int fd)
{
- struct syment *s, *e;
+ struct kernel_list_head *mod_fmt;
+ struct syment *s, *e, *b;
long bprintk_fmt_s, bprintk_fmt_e;
- char string[4096];
long *address;
size_t i, count;
@@ -3358,10 +3393,8 @@ static int save_ftrace_printk(int fd)
bprintk_fmt_e = e->value;
count = (bprintk_fmt_e - bprintk_fmt_s) / sizeof(long);
- if (count == 0) {
- unsigned int size = 0;
- return write_and_check(fd, &size, 4);
- }
+ if (count == 0)
+ goto do_mods;
address = malloc(count * sizeof(long));
if (address == NULL)
@@ -3374,37 +3407,49 @@ static int save_ftrace_printk(int fd)
}
for (i = 0; i < count; i++) {
- size_t len = read_string(address[i], string, sizeof(string));
- if (!len) {
+ if (add_print_address(address[i]) < 0) {
free(address);
return -1;
}
-
- tmp_fprintf("0x%lx : \"", address[i]);
-
- for (i = 0; string[i]; i++) {
- switch (string[i]) {
- case '\n':
- tmp_fprintf("\\n");
- break;
- case '\t':
- tmp_fprintf("\\t");
- break;
- case '\\':
- tmp_fprintf("\\\\");
- break;
- case '"':
- tmp_fprintf("\\\"");
- break;
- default:
- tmp_fprintf("%c", string[i]);
- }
- }
- tmp_fprintf("\"\n");
}
free(address);
+ do_mods:
+
+ /* Add modules */
+ b = symbol_search("trace_bprintk_fmt_list");
+ if (!b)
+ goto out;
+
+ mod_fmt = (struct kernel_list_head *)GETBUF(SIZE(list_head));
+ if (!readmem(b->value, KVADDR, mod_fmt,
+ SIZE(list_head), "trace_bprintk_fmt_list contents",
+ RETURN_ON_ERROR))
+ goto out_free;
+
+ while ((unsigned long)mod_fmt->next != b->value) {
+ unsigned long addr;
+
+ addr = (unsigned long)mod_fmt->next + SIZE(list_head);
+
+ if (!readmem((unsigned long)mod_fmt->next, KVADDR, mod_fmt,
+ SIZE(list_head), "trace_bprintk_fmt_list contents",
+ RETURN_ON_ERROR))
+ goto out_free;
+
+ if (add_print_address(addr) < 0)
+ goto out_free;
+ count++;
+ }
+
+ out_free:
+ FREEBUF(mod_fmt);
+ out:
+ if (count == 0) {
+ unsigned int size = 0;
+ return write_and_check(fd, &size, 4);
+ }
if (tmp_file_record_size4(fd))
return -1;
return tmp_file_flush(fd);
8:57 a.m.
New subject: [PATCH 3/3 v2] crash-trace-command: Update crash to handle new bprintk format structure
The bprintk format structure may change in the near future. Update the
reading of the structure to comply with the change.
Signed-off-by: Steven Rostedt <rostedt(a)goodmis.org>
Index: crash-5.1.3/extensions/trace.c
===================================================================
--- crash-5.1.3.orig/extensions/trace.c
+++ crash-5.1.3/extensions/trace.c
@@ -3383,6 +3383,7 @@ static int save_ftrace_printk(int fd)
long bprintk_fmt_s, bprintk_fmt_e;
long *address;
size_t i, count;
+ int addr_is_array = 0;
s = symbol_search("__start___trace_bprintk_fmt");
e = symbol_search("__stop___trace_bprintk_fmt");
@@ -3422,6 +3423,16 @@ static int save_ftrace_printk(int fd)
if (!b)
goto out;
+ switch (MEMBER_TYPE("trace_bprintk_fmt", "fmt")) {
+ case TYPE_CODE_ARRAY:
+ addr_is_array = 1;
+ break;
+ case TYPE_CODE_PTR:
+ default:
+ /* default not array */
+ break;
+ }
+
mod_fmt = (struct kernel_list_head *)GETBUF(SIZE(list_head));
if (!readmem(b->value, KVADDR, mod_fmt,
SIZE(list_head), "trace_bprintk_fmt_list contents",
@@ -3432,6 +3443,12 @@ static int save_ftrace_printk(int fd)
unsigned long addr;
addr = (unsigned long)mod_fmt->next + SIZE(list_head);
+ if (!addr_is_array) {
+ if (!readmem(addr, KVADDR, &addr, sizeof(addr),
+ "trace_bprintk_fmt_list fmt field",
+ RETURN_ON_ERROR))
+ goto out_free;
+ }
if (!readmem((unsigned long)mod_fmt->next, KVADDR, mod_fmt,
SIZE(list_head), "trace_bprintk_fmt_list contents",
9:43 a.m.
----- Original Message -----
These are update patches to have crash extract the trace_bprintk()
formats from a kernel core dump. It handles the current format
and a new format that I'll be pushing out after the merge window
has closed for Linux 2.6.40. The new format is required for the
kernel debugfs to export the same bprintk data as well.
This means that crash will be able to extract more information than
trace-cmd itself can on a running kernel :)
v2:
o Removed unused 'len' variable.
o Moved count == 0 fix into patch 2
-- Steve
The 3 patches apply just fine on top of Lai's latest patch.
Queued for the crash-5.1.4 release.
Thanks,
Dave
4996
days inactive
4996
days old
devel@lists.crash-utility.osci.io
4 comments
2 participants
participants (2)
-
Dave Anderson -
Steven Rostedt