The patch titled
Subject: lib/dump_stack: add dump_stack_print_cmdline() and wire up in dump_stack_print_info()
has been added to the -mm mm-nonmm-unstable branch. Its filename is
lib-dump_stack-add-dump_stack_print_cmdline-and-wire-up-in-dump_stack_print_info.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-dump_stack-add-dump_stack_print_cmdline-and-wire-up-in-dump_stack_print_info.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Helge Deller <deller@xxxxxx>
Subject: lib/dump_stack: add dump_stack_print_cmdline() and wire up in dump_stack_print_info()
Date: Mon, 8 Aug 2022 15:09:15 +0200
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
Josh Triplett noted that dumping such command line parameters into syslog
may theoretically lead to information disclosure. That's why this patch
checks the value of the kptr_restrict sysctl variable and will not print
any information if kptr_restrict==2, and will not show the program
parameters if kptr_restrict==1.
Link: https://lkml.kernel.org/r/20220808130917.30760-3-deller@xxxxxx
Signed-off-by: Helge Deller <deller@xxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/printk.h | 5 +++++
lib/dump_stack.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 39 insertions(+)
--- a/include/linux/printk.h~lib-dump_stack-add-dump_stack_print_cmdline-and-wire-up-in-dump_stack_print_info
+++ a/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_s
{
}
+static inline void dump_stack_print_cmdline(const char *log_lvl)
+{
+}
+
static inline void dump_stack_print_info(const char *log_lvl)
{
}
--- a/lib/dump_stack.c~lib-dump_stack-add-dump_stack_print_cmdline-and-wire-up-in-dump_stack_print_info
+++ a/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];
@@ -46,6 +47,37 @@ void __init dump_stack_set_arch_desc(con
#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];
+
+ if (kptr_restrict >= 2)
+ return; /* never show command line */
+
+ /* get command line */
+ get_task_cmdline_kernel(current, cmdline, sizeof(cmdline));
+
+ if (kptr_restrict == 1) {
+ char *p;
+
+ /* if restricted show program path only */
+ p = strchr(cmdline, ' ');
+ if (p) {
+ *p = 0;
+ strlcat(cmdline,
+ " ... [parameters hidden due to kptr_restrict]",
+ 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 +94,8 @@ void dump_stack_print_info(const char *l
(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);
_
Patches currently in -mm which might be from deller@xxxxxx are
proc-add-get_task_cmdline_kernel-function.patch
lib-dump_stack-add-dump_stack_print_cmdline-and-wire-up-in-dump_stack_print_info.patch
x86-fault-dump-command-line-of-faulting-process-to-syslog.patch
arc-use-generic-dump_stack_print_cmdline-implementation.patch
