Messages in this thread | | | Date | Mon, 20 Oct 2008 13:57:07 -0700 | From | Greg KH <> | Subject | Re: [PATCH 02/46] sysfs: crash debugging |
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On Thu, Oct 16, 2008 at 01:40:56PM -0400, Mathieu Desnoyers wrote: > * Greg Kroah-Hartman (gregkh@suse.de) wrote: > > From: Andrew Morton <akpm@linux-foundation.org> > > > > Print the name of the last-accessed sysfs file when we oops, to help track > > down oopses which occur in sysfs store/read handlers. Because these oopses > > tend to not leave any trace of the offending code in the stack traces. > > > > Cc: Kay Sievers <kay.sievers@vrfy.org> > > Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> > > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > > Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> > > --- > > arch/x86/kernel/dumpstack_32.c | 2 ++ > > arch/x86/kernel/dumpstack_64.c | 2 ++ > > fs/sysfs/file.c | 13 +++++++++++++ > > include/linux/sysfs.h | 6 ++++++ > > 4 files changed, 23 insertions(+), 0 deletions(-) > > > > diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c > > index 201ee35..1a78180 100644 > > --- a/arch/x86/kernel/dumpstack_32.c > > +++ b/arch/x86/kernel/dumpstack_32.c > > @@ -13,6 +13,7 @@ > > #include <linux/kexec.h> > > #include <linux/bug.h> > > #include <linux/nmi.h> > > +#include <linux/sysfs.h> > > > > #include <asm/stacktrace.h> > > > > @@ -343,6 +344,7 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err) > > printk("DEBUG_PAGEALLOC"); > > #endif > > printk("\n"); > > + sysfs_printk_last_file(); > > if (notify_die(DIE_OOPS, str, regs, err, > > current->thread.trap_no, SIGSEGV) == NOTIFY_STOP) > > return 1; > > diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c > > index 086cc81..96a5db7 100644 > > --- a/arch/x86/kernel/dumpstack_64.c > > +++ b/arch/x86/kernel/dumpstack_64.c > > @@ -13,6 +13,7 @@ > > #include <linux/kexec.h> > > #include <linux/bug.h> > > #include <linux/nmi.h> > > +#include <linux/sysfs.h> > > > > #include <asm/stacktrace.h> > > > > @@ -489,6 +490,7 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err) > > printk("DEBUG_PAGEALLOC"); > > #endif > > printk("\n"); > > + sysfs_printk_last_file(); > > if (notify_die(DIE_OOPS, str, regs, err, > > current->thread.trap_no, SIGSEGV) == NOTIFY_STOP) > > return 1; > > diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c > > index c9e4e50..ce8339c 100644 > > --- a/fs/sysfs/file.c > > +++ b/fs/sysfs/file.c > > @@ -19,10 +19,18 @@ > > #include <linux/poll.h> > > #include <linux/list.h> > > #include <linux/mutex.h> > > +#include <linux/limits.h> > > #include <asm/uaccess.h> > > > > #include "sysfs.h" > > > > +/* used in crash dumps to help with debugging */ > > +static char last_sysfs_file[PATH_MAX]; > > +void sysfs_printk_last_file(void) > > +{ > > + printk(KERN_EMERG "last sysfs file: %s\n", last_sysfs_file); > > +} > > + > > /* > > * There's one sysfs_buffer for each open file and one > > * sysfs_open_dirent for each sysfs_dirent with one or more open > > @@ -328,6 +336,11 @@ static int sysfs_open_file(struct inode *inode, struct file *file) > > struct sysfs_buffer *buffer; > > struct sysfs_ops *ops; > > int error = -EACCES; > > + char *p; > > + > > + p = d_path(&file->f_path, last_sysfs_file, sizeof(last_sysfs_file)); > > + if (p) > > if (!IS_ERR(p)) ? > > > + memmove(last_sysfs_file, p, strlen(p) + 1); > > > > Given we do a strlen() here anyway, shouldn't we just use strcpy ?
Probably would be good.
Care to send a patch for both of these?
thanks,
greg k-h
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