[PATCH 2/3] lib/dump_stack: Add dump_stack_print_cmdline() and wire up in dump_stack_print_info()

Helge Deller
2022-08-01T15:20:45Z

Add the function dump_stack_print_cmdline() which can be used by arch
code to print the command line of the current processs. This function
is useful in arch code when dumping information for a faulting process.

Wire this function up in the dump_stack_print_info() function to include
the dumping of the command line for architectures which use
dump_stack_print_info().

As an example, with this patch a failing glibc testcase (which uses
ld.so.1 as starting program) up to now reported just "ld.so.1" failing:

do_page_fault() command='ld.so.1' type=15 address=0x565921d8 in libc.so[f7339000+1bb000]
trap #15: Data TLB miss fault, vm_start = 0x0001a000, vm_end = 0x0001b000

and now it reports in addition:

ld.so.1[1151] cmdline: /home/gnu/glibc/objdir/elf/ld.so.1 --library-path /home/gnu/glibc/objdir:/home/gnu/glibc/objdir/math:/home/gnu/
/home/gnu/glibc/objdir/malloc/tst-safe-linking-malloc-hugetlb1

Signed-off-by: Helge Deller <deller@gmx.de>
---
include/linux/printk.h | 5 +++++
lib/dump_stack.c | 17 +++++++++++++++++
2 files changed, 22 insertions(+)

diff --git a/include/linux/printk.h b/include/linux/printk.h
index cf7d666ab1f8..5290a32a197d 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -191,6 +191,7 @@ u32 log_buf_len_get(void);
void log_buf_vmcoreinfo_setup(void);
void __init setup_log_buf(int early);
__printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...);
+void dump_stack_print_cmdline(const char *log_lvl);
void dump_stack_print_info(const char *log_lvl);
void show_regs_print_info(const char *log_lvl);
extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold;
@@ -262,6 +263,10 @@ static inline __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...)
{
}

+static inline void dump_stack_print_cmdline(const char *log_lvl)
+{
+}
+
static inline void dump_stack_print_info(const char *log_lvl)
{
}
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index 83471e81501a..c9b6a4c0c4e1 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -14,6 +14,7 @@
#include <linux/kexec.h>
#include <linux/utsname.h>
#include <linux/stop_machine.h>
+#include <linux/proc_fs.h>

static char dump_stack_arch_desc_str[128];

@@ -45,6 +46,20 @@ void __init dump_stack_set_arch_desc(const char *fmt, ...)
#define BUILD_ID_VAL ""
#endif

+/**
+ * dump_stack_print_cmdline - print the command line of current process
+ * @log_lvl: log level
+ */
+void dump_stack_print_cmdline(const char *log_lvl)
+{
+ char cmdline[256];
+
+ /* get command line */
+ get_task_cmdline_kernel(current, cmdline, sizeof(cmdline));
+ printk("%s%s[%d] cmdline: %s\n", log_lvl, current->comm,
+ current->pid, cmdline);
+}
+
/**
* dump_stack_print_info - print generic debug info for dump_stack()
* @log_lvl: log level
@@ -62,6 +77,8 @@ void dump_stack_print_info(const char *log_lvl)
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version, BUILD_ID_VAL);

+ dump_stack_print_cmdline(log_lvl);
+
if (dump_stack_arch_desc_str[0] != '\0')
printk("%sHardware name: %s\n",
log_lvl, dump_stack_arch_desc_str);
--
2.37.1