| Message ID | alpine.DEB.2.10.1403180922050.17965@nuc (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 03/18/2014 04:37 PM, Christoph Lameter wrote: > On Tue, 18 Mar 2014, Grygorii Strashko wrote: > >> diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c >> index a270dce..73a2004 100644 >> --- a/lib/smp_processor_id.c >> +++ b/lib/smp_processor_id.c >> @@ -58,9 +58,6 @@ EXPORT_SYMBOL(debug_smp_processor_id); >> >> notrace void __this_cpu_preempt_check(const char *op) >> { >> - char text[40]; >> - >> - snprintf(text, sizeof(text), "__this_cpu_%s()", op); >> - check_preemption_disabled(text); >> + check_preemption_disabled(op); >> } >> EXPORT_SYMBOL(__this_cpu_preempt_check); > > So it looks like there is an early this cpu operation in a context that > cannot handle snprintf. But the checks in check_preemption_disabled() > avoid processing there so that works. Just to be sure that I've described time point of issue correctly: [ 2.161746] dwc3 2690000.dwc3: failed to initialize core [ 2.167255] dwc3: probe of 2690000.dwc3 failed with error -38 [ 2.259687] Freeing unused kernel memory: 280K (c0678000 - c06be000) Please press Enter to activate this console. ^^^ system stall here Any way, I can boot and console works fine with your change :) Thanks. Tested-by: Grygorii Strashko <grygorii.strashko@ti.com> > > We could fix this by moving the string concatenation operation into > the check function. > > Index: linux/lib/smp_processor_id.c > =================================================================== > --- linux.orig/lib/smp_processor_id.c 2014-03-18 09:36:31.330450525 -0500 > +++ linux/lib/smp_processor_id.c 2014-03-18 09:36:37.822315534 -0500 > @@ -7,7 +7,8 @@ > #include <linux/kallsyms.h> > #include <linux/sched.h> > > -notrace static unsigned int check_preemption_disabled(char *what) > +notrace static unsigned int check_preemption_disabled(const char *what1, > + const char *what2) > { > int this_cpu = raw_smp_processor_id(); > > @@ -38,8 +39,8 @@ > if (!printk_ratelimit()) > goto out_enable; > > - printk(KERN_ERR "BUG: using %s in preemptible [%08x] code: %s/%d\n", > - what, preempt_count() - 1, current->comm, current->pid); > + printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n", > + what1, what2, preempt_count() - 1, current->comm, current->pid); > > print_symbol("caller is %s\n", (long)__builtin_return_address(0)); > dump_stack(); > @@ -52,15 +53,12 @@ > > notrace unsigned int debug_smp_processor_id(void) > { > - return check_preemption_disabled("smp_processor_id()"); > + return check_preemption_disabled("smp_processor_id",""); > } > EXPORT_SYMBOL(debug_smp_processor_id); > > notrace void __this_cpu_preempt_check(const char *op) > { > - char text[40]; > - > - snprintf(text, sizeof(text), "__this_cpu_%s()", op); > - check_preemption_disabled(text); > + check_preemption_disabled("__this_cpu_", op); > } > EXPORT_SYMBOL(__this_cpu_preempt_check); >
Index: linux/lib/smp_processor_id.c =================================================================== --- linux.orig/lib/smp_processor_id.c 2014-03-18 09:36:31.330450525 -0500 +++ linux/lib/smp_processor_id.c 2014-03-18 09:36:37.822315534 -0500 @@ -7,7 +7,8 @@ #include <linux/kallsyms.h> #include <linux/sched.h> -notrace static unsigned int check_preemption_disabled(char *what) +notrace static unsigned int check_preemption_disabled(const char *what1, + const char *what2) { int this_cpu = raw_smp_processor_id(); @@ -38,8 +39,8 @@ if (!printk_ratelimit()) goto out_enable; - printk(KERN_ERR "BUG: using %s in preemptible [%08x] code: %s/%d\n", - what, preempt_count() - 1, current->comm, current->pid); + printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n", + what1, what2, preempt_count() - 1, current->comm, current->pid); print_symbol("caller is %s\n", (long)__builtin_return_address(0)); dump_stack(); @@ -52,15 +53,12 @@ notrace unsigned int debug_smp_processor_id(void) { - return check_preemption_disabled("smp_processor_id()"); + return check_preemption_disabled("smp_processor_id",""); } EXPORT_SYMBOL(debug_smp_processor_id); notrace void __this_cpu_preempt_check(const char *op) { - char text[40]; - - snprintf(text, sizeof(text), "__this_cpu_%s()", op); - check_preemption_disabled(text); + check_preemption_disabled("__this_cpu_", op); } EXPORT_SYMBOL(__this_cpu_preempt_check);