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authorDmitry Safonov <dima@arista.com>2020-06-08 21:31:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-09 09:39:12 -0700
commitd46b3df78ad4b4c178f1035a35463cbc0ce768b2 (patch)
treef0b17b5b2f4935a3ab94cbf6741fe61297835791
parent5c0884694f7fd1efc846f720f10d190bf708e461 (diff)
downloadlinux-stericsson-d46b3df78ad4b4c178f1035a35463cbc0ce768b2.tar.gz
x86: add missing const qualifiers for log_lvl
Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user). Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred. Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers. Keep log_lvl const show_trace_log_lvl() and printk_stack_address() as the new generic show_stack_loglvl() wants to have a proper const qualifier. And gcc rightfully produces warnings in case it's not keept: arch/x86/kernel/dumpstack.c: In function `show_stack': arch/x86/kernel/dumpstack.c:294:37: warning: passing argument 4 of `show_trace_log_lv ' discards `const' qualifier from pointer target type [-Wdiscarded-qualifiers] 294 | show_trace_log_lvl(task, NULL, sp, loglvl); | ^~~~~~ arch/x86/kernel/dumpstack.c:163:32: note: expected `char *' but argument is of type `const char *' 163 | unsigned long *stack, char *log_lvl) | ~~~~~~^~~~~~~ [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20200418201944.482088-41-dima@arista.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/x86/include/asm/stacktrace.h2
-rw-r--r--arch/x86/kernel/dumpstack.c4
2 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h
index 14db05086bbf..5ae5a68e469d 100644
--- a/arch/x86/include/asm/stacktrace.h
+++ b/arch/x86/include/asm/stacktrace.h
@@ -87,7 +87,7 @@ get_stack_pointer(struct task_struct *task, struct pt_regs *regs)
}
void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
- unsigned long *stack, char *log_lvl);
+ unsigned long *stack, const char *log_lvl);
/* The form of the top of the frame on the stack */
struct stack_frame {
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index ae64ec7f752f..b94bc31a1757 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -65,7 +65,7 @@ bool in_entry_stack(unsigned long *stack, struct stack_info *info)
}
static void printk_stack_address(unsigned long address, int reliable,
- char *log_lvl)
+ const char *log_lvl)
{
touch_nmi_watchdog();
printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);
@@ -160,7 +160,7 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,
}
void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
- unsigned long *stack, char *log_lvl)
+ unsigned long *stack, const char *log_lvl)
{
struct unwind_state state;
struct stack_info stack_info = {0};