Messages in this thread Patch in this message | | | From | Dmitry Safonov <> | Subject | [PATCHv2 06/50] arm: Add loglvl to dump_backtrace() | Date | Mon, 16 Mar 2020 14:38:32 +0000 |
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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 dump_backtrace() as a preparation for introducing show_stack_loglvl().
As a good side-effect __die() now prints not only "Stack:" header with KERN_EMERG, but the backtrace itself.
Cc: Russell King <linux@armlinux.org.uk> Cc: Will Deacon <will@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: clang-built-linux@googlegroups.com [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u Signed-off-by: Dmitry Safonov <dima@arista.com> --- arch/arm/kernel/traps.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 685e17c2e275..0f09ace18e6c 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -202,17 +202,19 @@ 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) +static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk, + const char *loglvl) { - unwind_backtrace(regs, tsk, KERN_DEFAULT); + unwind_backtrace(regs, tsk, loglvl); } #else -static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) +static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk, + const char *loglvl) { unsigned int fp, mode; int ok = 1; - printk("Backtrace: "); + printk("%sBacktrace: ", loglvl); if (!tsk) tsk = current; @@ -239,13 +241,13 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) pr_cont("\n"); if (ok) - c_backtrace(fp, mode, NULL); + c_backtrace(fp, mode, loglvl); } #endif void show_stack(struct task_struct *tsk, unsigned long *sp) { - dump_backtrace(NULL, tsk); + dump_backtrace(NULL, tsk, KERN_DEFAULT); barrier(); } @@ -289,7 +291,7 @@ static int __die(const char *str, int err, struct pt_regs *regs) if (!user_mode(regs) || in_interrupt()) { dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, THREAD_SIZE + (unsigned long)task_stack_page(tsk)); - dump_backtrace(regs, tsk); + dump_backtrace(regs, tsk, KERN_EMERG); dump_instr(KERN_EMERG, regs); } -- 2.25.1
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