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authorDmitry Safonov <dima@arista.com>2020-06-08 21:30:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-09 09:39:10 -0700
commite8d7b7353216586f64f5bbcc024951e3cab10a60 (patch)
tree45529dfb97899f69fea275cb5c0dd98c747288ba /arch/arm
parent5489ab50c22771ddcad014968141b0d104d650a3 (diff)
downloadlinux-e8d7b7353216586f64f5bbcc024951e3cab10a60.tar.bz2
arm: add loglvl to unwind_backtrace()
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. Add log level argument to unwind_backtrace() as a preparation for introducing show_stack_loglvl(). As a good side-effect arm_syscall() is now printing errors with the same log level as the backtrace. [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: Russell King <linux@armlinux.org.uk> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/20200418201944.482088-6-dima@arista.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/include/asm/unwind.h3
-rw-r--r--arch/arm/kernel/traps.c6
-rw-r--r--arch/arm/kernel/unwind.c5
3 files changed, 8 insertions, 6 deletions
diff --git a/arch/arm/include/asm/unwind.h b/arch/arm/include/asm/unwind.h
index 6e282c33126b..0f8a3439902d 100644
--- a/arch/arm/include/asm/unwind.h
+++ b/arch/arm/include/asm/unwind.h
@@ -36,7 +36,8 @@ extern struct unwind_table *unwind_table_add(unsigned long start,
unsigned long text_addr,
unsigned long text_size);
extern void unwind_table_del(struct unwind_table *tab);
-extern void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk);
+extern void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+ const char *loglvl);
#endif /* !__ASSEMBLY__ */
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 7bba15fdce9f..aef52a401ad5 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -204,7 +204,7 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
#ifdef CONFIG_ARM_UNWIND
static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
{
- unwind_backtrace(regs, tsk);
+ unwind_backtrace(regs, tsk, KERN_DEFAULT);
}
#else
static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
@@ -664,10 +664,10 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
if (user_debug & UDBG_SYSCALL) {
pr_err("[%d] %s: arm syscall %d\n",
task_pid_nr(current), current->comm, no);
- dump_instr("", regs);
+ dump_instr(KERN_ERR, regs);
if (user_mode(regs)) {
__show_regs(regs);
- c_backtrace(frame_pointer(regs), processor_mode(regs), NULL);
+ c_backtrace(frame_pointer(regs), processor_mode(regs), KERN_ERR);
}
}
#endif
diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index 343cc27b36c4..d2bd0df2318d 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -455,7 +455,8 @@ int unwind_frame(struct stackframe *frame)
return URC_OK;
}
-void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+ const char *loglvl)
{
struct stackframe frame;
@@ -493,7 +494,7 @@ void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk)
urc = unwind_frame(&frame);
if (urc < 0)
break;
- dump_backtrace_entry(where, frame.pc, frame.sp - 4, NULL);
+ dump_backtrace_entry(where, frame.pc, frame.sp - 4, loglvl);
}
}