Currently when kdb traps printk messages then the raw log level prefix (consisting of '\001' followed by a numeral) does not get stripped off before the message is issued to the various I/O handlers supported by kdb. This causes annoying visual noise as well as causing problems grepping for ^. It is also a change of behaviour compared to normal usage of printk() usage. For example <SysRq>-h ends up with different output to that of kdb's "sr h". This patch addresses the problem by stripping log levels from messages before they are issued to the I/O handlers. printk() which can also act as an i/o handler in some cases is special cased; if the caller provided a log level then the prefix will be preserved when sent to printk(). The addition of non-printable characters to the output of kdb commands is a regression, albeit and extremely elderly one, introduced by commit 04d2c8c83d0e ("printk: convert the format for KERN_<LEVEL> to a 2 byte pattern"). Note also that this patch does *not* restore the original behaviour from v3.5. Instead it makes printk() from within a kdb command display the message without any prefix (i.e. like printk() normally does).
Unified · Split
| @@ -156,8 +156,14 @@ typedef enum { · 155 unmodified lines | ||
| 156 | 156 | KDB_REASON_SYSTEM_NMI, /* In NMI due to SYSTEM cmd; regs valid */ |
| 157 | 157 | } kdb_reason_t; |
| 158 | 158 | |
| 159 | +enum kdb_msgsrc { | |
| 160 | + KDB_MSGSRC_INTERNAL, /* direct call to kdb_printf() */ | |
| 161 | + KDB_MSGSRC_PRINTK, /* trapped from printk() */ | |
| 162 | +}; | |
| 163 | + | |
| 159 | 164 | extern int kdb_trap_printk; |
| 160 | −extern __printf(1, 0) int vkdb_printf(const char *fmt, va_list args); | |
| 165 | +extern __printf(2, 0) int vkdb_printf(enum kdb_msgsrc src, const char *fmt, | |
| 166 | + va_list args); | |
| 161 | 167 | extern __printf(1, 2) int kdb_printf(const char *, ...); |
| 162 | 168 | typedef __printf(1, 2) int (*kdb_printf_t)(const char *, ...); |
| 163 | 169 | |
| @@ -548,7 +548,7 @@ static int kdb_search_string(char *searched, char *searchfor) · 547 unmodified lines | ||
| 548 | 548 | return 0; |
| 549 | 549 | } |
| 550 | 550 | |
| 551 | −int vkdb_printf(const char *fmt, va_list ap) | |
| 551 | +int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap) | |
| 552 | 552 | { |
| 553 | 553 | int diag; |
| 554 | 554 | int linecount; |
| @@ -691,19 +691,20 @@ kdb_printit: · 136 unmodified lines | ||
| 691 | 691 | * Write to all consoles. |
| 692 | 692 | */ |
| 693 | 693 | retlen = strlen(kdb_buffer); |
| 694 | + cp = (char *) printk_skip_level(kdb_buffer); | |
| 694 | 695 | if (!dbg_kdb_mode && kgdb_connected) { |
| 695 | − gdbstub_msg_write(kdb_buffer, retlen); | |
| 696 | + gdbstub_msg_write(cp, retlen - (cp - kdb_buffer)); | |
| 696 | 697 | } else { |
| 697 | 698 | if (dbg_io_ops && !dbg_io_ops->is_console) { |
| 698 | − len = retlen; | |
| 699 | − cp = kdb_buffer; | |
| 699 | + len = retlen - (cp - kdb_buffer); | |
| 700 | + cp2 = cp; | |
| 700 | 701 | while (len--) { |
| 701 | − dbg_io_ops->write_char(*cp); | |
| 702 | − cp++; | |
| 702 | + dbg_io_ops->write_char(*cp2); | |
| 703 | + cp2++; | |
| 703 | 704 | } |
| 704 | 705 | } |
| 705 | 706 | while (c) { |
| 706 | − c->write(c, kdb_buffer, retlen); | |
| 707 | + c->write(c, cp, retlen - (cp - kdb_buffer)); | |
| 707 | 708 | touch_nmi_watchdog(); |
| 708 | 709 | c = c->next; |
| 709 | 710 | } |
| @@ -711,7 +712,10 @@ kdb_printit: · 1 unmodified line | ||
| 711 | 712 | if (logging) { |
| 712 | 713 | saved_loglevel = console_loglevel; |
| 713 | 714 | console_loglevel = CONSOLE_LOGLEVEL_SILENT; |
| 714 | − printk(KERN_INFO "%s", kdb_buffer); | |
| 715 | + if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK) | |
| 716 | + printk("%s", kdb_buffer); | |
| 717 | + else | |
| 718 | + pr_info("%s", kdb_buffer); | |
| 715 | 719 | } |
| 716 | 720 | |
| 717 | 721 | if (KDB_STATE(PAGER)) { |
| @@ -844,7 +848,7 @@ int kdb_printf(const char *fmt, ...) · 126 unmodified lines | ||
| 844 | 848 | int r; |
| 845 | 849 | |
| 846 | 850 | va_start(ap, fmt); |
| 847 | − r = vkdb_printf(fmt, ap); | |
| 851 | + r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap); | |
| 848 | 852 | va_end(ap); |
| 849 | 853 | |
| 850 | 854 | return r; |
| @@ -1811,7 +1811,7 @@ int vprintk_default(const char *fmt, va_list args) · 1810 unmodified lines | ||
| 1811 | 1811 | |
| 1812 | 1812 | #ifdef CONFIG_KGDB_KDB |
| 1813 | 1813 | if (unlikely(kdb_trap_printk)) { |
| 1814 | − r = vkdb_printf(fmt, args); | |
| 1814 | + r = vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args); | |
| 1815 | 1815 | return r; |
| 1816 | 1816 | } |
| 1817 | 1817 | #endif |