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d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=21OEOBe1K5oTTDMQpZL0edPMTp3mnTLWpfEDMEehxWE=; b=FzsTXJyi3jq2fVuESPcShzRJeo/cuBGBLvFeBOQcPgxzeREkdg738V9sJScVe87PZJ hdD4qIulDlTjN7LHbBJ/iGZGOJ6xVepgXP20aN3f743Qrq/it4/d6qg8QVBzhTi1Tg5I Yd/WXmlwWWHObB7oXixFZgMXihp8hOoCDC9uiLoP4qBj1cO9iH7zr4omhYMD7nFezJbm hy2+4w0DkYepu/PsPmCECe46a5HT0viFXfIXvtZVNXg09BnbsYP5UD8FqBpr5V7AH1tT gOUB36h0+kV8VgZkUz3bf/EHSC4lKsIbhtLvZdfH/Q1XMbk1efFNHUEeVso36eFYpaXI M2ZA== X-Gm-Message-State: AOAM531Qe9ZoVGzpzO2IIR+kJxmhP79S3fEa90/3s0vBUiUcD9gdcxrc 27q70aD1gKfw08P+T9H9OsIxGgjndPsg4EAbclpTYQ== X-Google-Smtp-Source: ABdhPJxqK6g7FBn8y/9deqo13s8LUGLEcZnzibISWzr3+KDwpNeWRbr5rwr5HCFsQdWytLfdfjaioOHfrroFwHFEU0I= X-Received: by 2002:a05:6830:410e:: with SMTP id w14mr22346686ott.251.1620211049895; Wed, 05 May 2021 03:37:29 -0700 (PDT) MIME-Version: 1.0 References: <20210505092218.2422386-1-glider@google.com> In-Reply-To: <20210505092218.2422386-1-glider@google.com> From: Marco Elver Date: Wed, 5 May 2021 12:37:18 +0200 Message-ID: Subject: Re: [PATCH 1/2] printk: introduce dump_stack_lvl() To: Alexander Potapenko Cc: Andrew Morton , Petr Mladek , Ingo Molnar , bo.he@intel.com, yanmin_zhang@linux.intel.com, psodagud@quicinc.com, Dmitry Vyukov , LKML , Andrey Ryabinin , he@google.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 5 May 2021 at 11:22, Alexander Potapenko wrote: > dump_stack() is used for many different cases, which may require a log > level consistent with other kernel messages surrounding the dump_stack() > call. > Without that, certain systems that are configured to ignore the default > level messages will miss stack traces in critical error reports. > > This patch introduces dump_stack_lvl() that behaves similarly to > dump_stack(), but accepts a custom log level. > The old dump_stack() becomes equal to dump_stack_lvl(KERN_DEFAULT). > > A somewhat similar patch has been proposed in 2012: > https://lore.kernel.org/lkml/1332493269.2359.9.camel@hebo/ > , but wasn't merged. > > Cc: Andrew Morton > Cc: Petr Mladek > Cc: Ingo Molnar > Cc: he, bo > Cc: Yanmin Zhang > Cc: Prasad Sodagudi > Cc: Dmitry Vyukov > Cc: Marco Elver > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Alexander Potapenko > --- > include/linux/printk.h | 1 + > lib/dump_stack.c | 19 ++++++++++++------- > 2 files changed, 13 insertions(+), 7 deletions(-) > > diff --git a/include/linux/printk.h b/include/linux/printk.h > index fe7eb2351610..abe274305d79 100644 > --- a/include/linux/printk.h > +++ b/include/linux/printk.h > @@ -206,6 +206,7 @@ void __init setup_log_buf(int early); > __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...); > 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; > extern asmlinkage void dump_stack(void) __cold; > extern void printk_safe_flush(void); > extern void printk_safe_flush_on_panic(void); > diff --git a/lib/dump_stack.c b/lib/dump_stack.c > index f5a33b6f773f..3d2c324a4929 100644 > --- a/lib/dump_stack.c > +++ b/lib/dump_stack.c > @@ -73,10 +73,10 @@ void show_regs_print_info(const char *log_lvl) > dump_stack_print_info(log_lvl); > } > > -static void __dump_stack(void) > +static void __dump_stack(const char *log_lvl) > { > - dump_stack_print_info(KERN_DEFAULT); > - show_stack(NULL, NULL, KERN_DEFAULT); > + dump_stack_print_info(log_lvl); > + show_stack(NULL, NULL, log_lvl); > } > > /** > @@ -87,7 +87,7 @@ static void __dump_stack(void) > #ifdef CONFIG_SMP > static atomic_t dump_lock = ATOMIC_INIT(-1); > > -asmlinkage __visible void dump_stack(void) > +asmlinkage __visible void dump_stack_lvl(const char *log_lvl) > { > unsigned long flags; > int was_locked; > @@ -117,7 +117,7 @@ asmlinkage __visible void dump_stack(void) > goto retry; > } > > - __dump_stack(); > + __dump_stack(log_lvl); > > if (!was_locked) > atomic_set(&dump_lock, -1); > @@ -125,9 +125,14 @@ asmlinkage __visible void dump_stack(void) > local_irq_restore(flags); > } > #else > -asmlinkage __visible void dump_stack(void) > +asmlinkage __visible void dump_stack_lvl(const char *log_lvl) > { > - __dump_stack(); > + __dump_stack(log_lvl); > } > #endif +EXPORT_SYMBOL(dump_stack_lvl); is missing here? > + > +asmlinkage __visible void dump_stack(void) > +{ > + dump_stack_lvl(KERN_DEFAULT); > +} > EXPORT_SYMBOL(dump_stack); > -- > 2.31.1.527.g47e6f16901-goog >