Certain calls from the kdb shell will call out to printk(), and any of these calls should get vectored back to the kdb_printf() so that the kdb pager and processing can be used, as well as to properly channel I/O to the polled I/O devices.
CC: Randy Dunlap <[email protected]> CC: Andrew Morton <[email protected]> Signed-off-by: Jason Wessel <[email protected]> --- include/linux/kdb.h | 3 +++ kernel/debug/kdb/kdb_bt.c | 2 ++ kernel/debug/kdb/kdb_io.c | 24 ++++++++++++++++++++---- kernel/debug/kdb/kdb_main.c | 4 ++++ kernel/printk.c | 9 +++++++++ 5 files changed, 38 insertions(+), 4 deletions(-) diff --git a/include/linux/kdb.h b/include/linux/kdb.h index bff071e..118fd49 100644 --- a/include/linux/kdb.h +++ b/include/linux/kdb.h @@ -80,6 +80,9 @@ typedef enum { KDB_REASON_SSTEP, /* Single Step trap. - regs valid */ } kdb_reason_t; +extern int kdb_trap_printk; +extern int vkdb_printf(const char *fmt, va_list args) + __attribute__ ((format (printf, 1, 0))); extern int kdb_printf(const char *, ...) __attribute__ ((format (printf, 1, 2))); typedef int (*kdb_printf_t)(const char *, ...) diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c index c73402c..176da1a 100644 --- a/kernel/debug/kdb/kdb_bt.c +++ b/kernel/debug/kdb/kdb_bt.c @@ -23,6 +23,7 @@ static void kdb_show_stack(struct task_struct *p, void *addr) { int old_lvl = console_loglevel; console_loglevel = 15; + kdb_trap_printk++; kdb_set_current_task(p); if (addr) { show_stack((struct task_struct *)p, addr); @@ -36,6 +37,7 @@ static void kdb_show_stack(struct task_struct *p, void *addr) show_stack(p, NULL); } console_loglevel = old_lvl; + kdb_trap_printk--; } /* diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index 32d5521..dd75c20 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -29,6 +29,7 @@ #define CMD_BUFLEN 256 char kdb_prompt_str[CMD_BUFLEN]; +int kdb_trap_printk; static void kgdb_transition_check(char *buffer) { @@ -532,12 +533,12 @@ static int kdb_search_string(char *searched, char *searchfor) return 0; } -int kdb_printf(const char *fmt, ...) +int vkdb_printf(const char *fmt, va_list ap) { - va_list ap; int diag; int linecount; int logging, saved_loglevel = 0; + int saved_trap_printk; int got_printf_lock = 0; int retlen = 0; int fnd, len; @@ -548,6 +549,9 @@ int kdb_printf(const char *fmt, ...) unsigned long uninitialized_var(flags); preempt_disable(); + saved_trap_printk = kdb_trap_printk; + kdb_trap_printk = 0; + /* Serialize kdb_printf if multiple cpus try to write at once. * But if any cpu goes recursive in kdb, just print the output, * even if it is interleaved with any other text. @@ -574,9 +578,7 @@ int kdb_printf(const char *fmt, ...) next_avail = kdb_buffer; size_avail = sizeof(kdb_buffer); } - va_start(ap, fmt); vsnprintf(next_avail, size_avail, fmt, ap); - va_end(ap); /* * If kdb_parse() found that the command was cmd xxx | grep yyy @@ -804,6 +806,20 @@ kdb_print_out: } else { __release(kdb_printf_lock); } + kdb_trap_printk = saved_trap_printk; preempt_enable(); return retlen; } + +int kdb_printf(const char *fmt, ...) +{ + va_list ap; + int r; + + va_start(ap, fmt); + r = vkdb_printf(fmt, ap); + va_end(ap); + + return r; +} + diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 59bb68d..852e003 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -1056,7 +1056,9 @@ static void kdb_dumpregs(struct pt_regs *regs) { int old_lvl = console_loglevel; console_loglevel = 15; + kdb_trap_printk++; show_regs(regs); + kdb_trap_printk--; kdb_printf("\n"); console_loglevel = old_lvl; } @@ -1837,7 +1839,9 @@ static int kdb_sr(int argc, const char **argv) __sysrq_enabled = 1; } + kdb_trap_printk++; handle_sysrq(*argv[1], NULL); + kdb_trap_printk--; return 0; } diff --git a/kernel/printk.c b/kernel/printk.c index 9bee02e..cd17a79 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -33,6 +33,7 @@ #include <linux/bootmem.h> #include <linux/syscalls.h> #include <linux/kexec.h> +#include <linux/kdb.h> #include <linux/ratelimit.h> #include <linux/kmsg_dump.h> @@ -609,6 +610,14 @@ asmlinkage int printk(const char *fmt, ...) va_list args; int r; +#ifdef CONFIG_KGDB_KDB + if (unlikely(kdb_trap_printk)) { + va_start(args, fmt); + r = vkdb_printf(fmt, args); + va_end(args); + return r; + } +#endif va_start(args, fmt); r = vprintk(fmt, args); va_end(args); -- 1.6.3.1.9.g95405b ------------------------------------------------------------------------------ Throughout its 18-year history, RSA Conference consistently attracts the world's best and brightest in the field, creating opportunities for Conference attendees to learn about information security's most important issues through interactions with peers, luminaries and emerging and established companies. http://p.sf.net/sfu/rsaconf-dev2dev _______________________________________________ Kgdb-bugreport mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
