| Message ID | 4f75c511d209281967ff8eaa97a75d38d5346903.1308131436.git.laijs@cn.fujitsu.com |
|---|---|
| State | Rejected, archived |
| Headers | show |
On Thu, 2011-06-16 at 09:47 +0800, Lai Jiangshan wrote: > TP_printk() is not inside the RCU critical section, so the return value > of jbd2_dev_to_name() may be invalid. This fix pass a devname argument to > store the result name to void this problem. > > And ftrace_print_bdevname() is introduced to wrap > trace_seq_reserve() and jbd2_dev_to_name(). > > Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Ted, Are you going to take these patches? Probably too late for 3.0, but maybe can get them into 3.1? -- Steve > --- > fs/jbd2/journal.c | 27 ++++++++++++--------------- > include/linux/ftrace_event.h | 10 ++++++++++ > include/linux/jbd2.h | 6 +++--- > include/trace/events/jbd2.h | 15 ++++++++------- > 4 files changed, 33 insertions(+), 25 deletions(-) > > diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c > index 1c45b6a..c37597a 100644 > --- a/fs/jbd2/journal.c > +++ b/fs/jbd2/journal.c > @@ -2427,11 +2427,8 @@ static void __exit journal_exit(void) > * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 > * tracing infrastructure to map a dev_t to a device name. > * > - * The caller should use rcu_read_lock() in order to make sure the > - * device name stays valid until its done with it. We use > - * rcu_read_lock() as well to make sure we're safe in case the caller > - * gets sloppy, and because rcu_read_lock() is cheap and can be safely > - * nested. > + * We use caches to cache the results and use rcu_read_lock() > + * to protect the caches. > */ > struct devname_cache { > struct rcu_head rcu; > @@ -2442,34 +2439,35 @@ struct devname_cache { > static struct devname_cache __rcu *devcache[1 << CACHE_SIZE_BITS]; > static DEFINE_SPINLOCK(devname_cache_lock); > > -const char *jbd2_dev_to_name(dev_t device) > +void jbd2_dev_to_name(dev_t device, char *devname) > { > int i = hash_32(device, CACHE_SIZE_BITS); > - char *ret; > struct block_device *bd; > static struct devname_cache *cache; > > rcu_read_lock(); > cache = rcu_dereference(devcache[i]); > if (cache && cache->device == device) { > - ret = cache->devname; > + memcpy(devname, cache->devname, BDEVNAME_SIZE); > rcu_read_unlock(); > - return ret; > + return; > } > rcu_read_unlock(); > > cache = kmalloc(sizeof(struct devname_cache), GFP_KERNEL); > - if (!cache) > - return "NODEV-ALLOCFAILURE"; /* Something non-NULL */ > + if (!cache) { > + __bdevname(device, devname); > + return; > + } > bd = bdget(device); > spin_lock(&devname_cache_lock); > if (devcache[i]) { > if (devcache[i]->device == device) { > kfree(cache); > bdput(bd); > - ret = devcache[i]->devname; > + memcpy(devname, devcache[i]->devname, BDEVNAME_SIZE); > spin_unlock(&devname_cache_lock); > - return ret; > + return; > } > kfree_rcu(devcache[i], rcu); > } > @@ -2480,9 +2478,8 @@ const char *jbd2_dev_to_name(dev_t device) > } else > __bdevname(device, cache->devname); > rcu_assign_pointer(devcache[i], cache); > - ret = cache->devname; > + memcpy(devname, cache->devname, BDEVNAME_SIZE); > spin_unlock(&devname_cache_lock); > - return ret; > } > EXPORT_SYMBOL(jbd2_dev_to_name); > > diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h > index 59d3ef1..2959ead 100644 > --- a/include/linux/ftrace_event.h > +++ b/include/linux/ftrace_event.h > @@ -6,6 +6,7 @@ > #include <linux/percpu.h> > #include <linux/hardirq.h> > #include <linux/perf_event.h> > +#include <linux/jbd2.h> > > struct trace_array; > struct tracer; > @@ -28,6 +29,15 @@ const char *ftrace_print_flags_seq(struct trace_seq *p, const char *delim, > const char *ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val, > const struct trace_print_flags *symbol_array); > > +static inline const char *ftrace_print_bdevname(struct trace_seq *p, dev_t device) > +{ > + char *bdevname = trace_seq_reserve(p, BDEVNAME_SIZE); > + > + jbd2_dev_to_name(device, bdevname); > + > + return bdevname; > +} > + > #if BITS_PER_LONG == 32 > const char *ftrace_print_symbols_seq_u64(struct trace_seq *p, > unsigned long long val, > diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h > index 4ecb7b1..964f375 100644 > --- a/include/linux/jbd2.h > +++ b/include/linux/jbd2.h > @@ -1331,11 +1331,11 @@ extern int jbd_blocks_per_page(struct inode *inode); > #define BUFFER_TRACE2(bh, bh2, info) do {} while (0) > #define JBUFFER_TRACE(jh, info) do {} while (0) > > -/* > - * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 > +/* > + * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 > * tracing infrastructure to map a dev_t to a device name. > */ > -extern const char *jbd2_dev_to_name(dev_t device); > +extern void jbd2_dev_to_name(dev_t device, char *bdevname); > > #endif /* __KERNEL__ */ > > diff --git a/include/trace/events/jbd2.h b/include/trace/events/jbd2.h > index bf16545..a9c8b44 100644 > --- a/include/trace/events/jbd2.h > +++ b/include/trace/events/jbd2.h > @@ -27,7 +27,7 @@ TRACE_EVENT(jbd2_checkpoint, > ), > > TP_printk("dev %s result %d", > - jbd2_dev_to_name(__entry->dev), __entry->result) > + ftrace_print_bdevname(p, __entry->dev), __entry->result) > ); > > DECLARE_EVENT_CLASS(jbd2_commit, > @@ -49,7 +49,7 @@ DECLARE_EVENT_CLASS(jbd2_commit, > ), > > TP_printk("dev %s transaction %d sync %d", > - jbd2_dev_to_name(__entry->dev), __entry->transaction, > + ftrace_print_bdevname(p, __entry->dev), __entry->transaction, > __entry->sync_commit) > ); > > @@ -101,7 +101,7 @@ TRACE_EVENT(jbd2_end_commit, > ), > > TP_printk("dev %s transaction %d sync %d head %d", > - jbd2_dev_to_name(__entry->dev), __entry->transaction, > + ftrace_print_bdevname(p, __entry->dev), __entry->transaction, > __entry->sync_commit, __entry->head) > ); > > @@ -121,7 +121,8 @@ TRACE_EVENT(jbd2_submit_inode_data, > ), > > TP_printk("dev %s ino %lu", > - jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino) > + ftrace_print_bdevname(p, __entry->dev), > + (unsigned long) __entry->ino) > ); > > TRACE_EVENT(jbd2_run_stats, > @@ -158,7 +159,7 @@ TRACE_EVENT(jbd2_run_stats, > > TP_printk("dev %s tid %lu wait %u running %u locked %u flushing %u " > "logging %u handle_count %u blocks %u blocks_logged %u", > - jbd2_dev_to_name(__entry->dev), __entry->tid, > + ftrace_print_bdevname(p, __entry->dev), __entry->tid, > jiffies_to_msecs(__entry->wait), > jiffies_to_msecs(__entry->running), > jiffies_to_msecs(__entry->locked), > @@ -194,7 +195,7 @@ TRACE_EVENT(jbd2_checkpoint_stats, > > TP_printk("dev %s tid %lu chp_time %u forced_to_close %u " > "written %u dropped %u", > - jbd2_dev_to_name(__entry->dev), __entry->tid, > + ftrace_print_bdevname(p, __entry->dev), __entry->tid, > jiffies_to_msecs(__entry->chp_time), > __entry->forced_to_close, __entry->written, __entry->dropped) > ); > @@ -223,7 +224,7 @@ TRACE_EVENT(jbd2_cleanup_journal_tail, > ), > > TP_printk("dev %s from %u to %u offset %lu freed %lu", > - jbd2_dev_to_name(__entry->dev), __entry->tail_sequence, > + ftrace_print_bdevname(p, __entry->dev), __entry->tail_sequence, > __entry->first_tid, __entry->block_nr, __entry->freed) > ); > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jul 07, 2011 at 10:06:24PM -0400, Steven Rostedt wrote: > On Thu, 2011-06-16 at 09:47 +0800, Lai Jiangshan wrote: > > TP_printk() is not inside the RCU critical section, so the return value > > of jbd2_dev_to_name() may be invalid. This fix pass a devname argument to > > store the result name to void this problem. > > > > And ftrace_print_bdevname() is introduced to wrap > > trace_seq_reserve() and jbd2_dev_to_name(). > > > > Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> > > Acked-by: Steven Rostedt <rostedt@goodmis.org> > > Ted, > > Are you going to take these patches? Probably too late for 3.0, but > maybe can get them into 3.1? Me too. Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > -- Steve > > > --- > > fs/jbd2/journal.c | 27 ++++++++++++--------------- > > include/linux/ftrace_event.h | 10 ++++++++++ > > include/linux/jbd2.h | 6 +++--- > > include/trace/events/jbd2.h | 15 ++++++++------- > > 4 files changed, 33 insertions(+), 25 deletions(-) > > > > diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c > > index 1c45b6a..c37597a 100644 > > --- a/fs/jbd2/journal.c > > +++ b/fs/jbd2/journal.c > > @@ -2427,11 +2427,8 @@ static void __exit journal_exit(void) > > * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 > > * tracing infrastructure to map a dev_t to a device name. > > * > > - * The caller should use rcu_read_lock() in order to make sure the > > - * device name stays valid until its done with it. We use > > - * rcu_read_lock() as well to make sure we're safe in case the caller > > - * gets sloppy, and because rcu_read_lock() is cheap and can be safely > > - * nested. > > + * We use caches to cache the results and use rcu_read_lock() > > + * to protect the caches. > > */ > > struct devname_cache { > > struct rcu_head rcu; > > @@ -2442,34 +2439,35 @@ struct devname_cache { > > static struct devname_cache __rcu *devcache[1 << CACHE_SIZE_BITS]; > > static DEFINE_SPINLOCK(devname_cache_lock); > > > > -const char *jbd2_dev_to_name(dev_t device) > > +void jbd2_dev_to_name(dev_t device, char *devname) > > { > > int i = hash_32(device, CACHE_SIZE_BITS); > > - char *ret; > > struct block_device *bd; > > static struct devname_cache *cache; > > > > rcu_read_lock(); > > cache = rcu_dereference(devcache[i]); > > if (cache && cache->device == device) { > > - ret = cache->devname; > > + memcpy(devname, cache->devname, BDEVNAME_SIZE); > > rcu_read_unlock(); > > - return ret; > > + return; > > } > > rcu_read_unlock(); > > > > cache = kmalloc(sizeof(struct devname_cache), GFP_KERNEL); > > - if (!cache) > > - return "NODEV-ALLOCFAILURE"; /* Something non-NULL */ > > + if (!cache) { > > + __bdevname(device, devname); > > + return; > > + } > > bd = bdget(device); > > spin_lock(&devname_cache_lock); > > if (devcache[i]) { > > if (devcache[i]->device == device) { > > kfree(cache); > > bdput(bd); > > - ret = devcache[i]->devname; > > + memcpy(devname, devcache[i]->devname, BDEVNAME_SIZE); > > spin_unlock(&devname_cache_lock); > > - return ret; > > + return; > > } > > kfree_rcu(devcache[i], rcu); > > } > > @@ -2480,9 +2478,8 @@ const char *jbd2_dev_to_name(dev_t device) > > } else > > __bdevname(device, cache->devname); > > rcu_assign_pointer(devcache[i], cache); > > - ret = cache->devname; > > + memcpy(devname, cache->devname, BDEVNAME_SIZE); > > spin_unlock(&devname_cache_lock); > > - return ret; > > } > > EXPORT_SYMBOL(jbd2_dev_to_name); > > > > diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h > > index 59d3ef1..2959ead 100644 > > --- a/include/linux/ftrace_event.h > > +++ b/include/linux/ftrace_event.h > > @@ -6,6 +6,7 @@ > > #include <linux/percpu.h> > > #include <linux/hardirq.h> > > #include <linux/perf_event.h> > > +#include <linux/jbd2.h> > > > > struct trace_array; > > struct tracer; > > @@ -28,6 +29,15 @@ const char *ftrace_print_flags_seq(struct trace_seq *p, const char *delim, > > const char *ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val, > > const struct trace_print_flags *symbol_array); > > > > +static inline const char *ftrace_print_bdevname(struct trace_seq *p, dev_t device) > > +{ > > + char *bdevname = trace_seq_reserve(p, BDEVNAME_SIZE); > > + > > + jbd2_dev_to_name(device, bdevname); > > + > > + return bdevname; > > +} > > + > > #if BITS_PER_LONG == 32 > > const char *ftrace_print_symbols_seq_u64(struct trace_seq *p, > > unsigned long long val, > > diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h > > index 4ecb7b1..964f375 100644 > > --- a/include/linux/jbd2.h > > +++ b/include/linux/jbd2.h > > @@ -1331,11 +1331,11 @@ extern int jbd_blocks_per_page(struct inode *inode); > > #define BUFFER_TRACE2(bh, bh2, info) do {} while (0) > > #define JBUFFER_TRACE(jh, info) do {} while (0) > > > > -/* > > - * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 > > +/* > > + * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 > > * tracing infrastructure to map a dev_t to a device name. > > */ > > -extern const char *jbd2_dev_to_name(dev_t device); > > +extern void jbd2_dev_to_name(dev_t device, char *bdevname); > > > > #endif /* __KERNEL__ */ > > > > diff --git a/include/trace/events/jbd2.h b/include/trace/events/jbd2.h > > index bf16545..a9c8b44 100644 > > --- a/include/trace/events/jbd2.h > > +++ b/include/trace/events/jbd2.h > > @@ -27,7 +27,7 @@ TRACE_EVENT(jbd2_checkpoint, > > ), > > > > TP_printk("dev %s result %d", > > - jbd2_dev_to_name(__entry->dev), __entry->result) > > + ftrace_print_bdevname(p, __entry->dev), __entry->result) > > ); > > > > DECLARE_EVENT_CLASS(jbd2_commit, > > @@ -49,7 +49,7 @@ DECLARE_EVENT_CLASS(jbd2_commit, > > ), > > > > TP_printk("dev %s transaction %d sync %d", > > - jbd2_dev_to_name(__entry->dev), __entry->transaction, > > + ftrace_print_bdevname(p, __entry->dev), __entry->transaction, > > __entry->sync_commit) > > ); > > > > @@ -101,7 +101,7 @@ TRACE_EVENT(jbd2_end_commit, > > ), > > > > TP_printk("dev %s transaction %d sync %d head %d", > > - jbd2_dev_to_name(__entry->dev), __entry->transaction, > > + ftrace_print_bdevname(p, __entry->dev), __entry->transaction, > > __entry->sync_commit, __entry->head) > > ); > > > > @@ -121,7 +121,8 @@ TRACE_EVENT(jbd2_submit_inode_data, > > ), > > > > TP_printk("dev %s ino %lu", > > - jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino) > > + ftrace_print_bdevname(p, __entry->dev), > > + (unsigned long) __entry->ino) > > ); > > > > TRACE_EVENT(jbd2_run_stats, > > @@ -158,7 +159,7 @@ TRACE_EVENT(jbd2_run_stats, > > > > TP_printk("dev %s tid %lu wait %u running %u locked %u flushing %u " > > "logging %u handle_count %u blocks %u blocks_logged %u", > > - jbd2_dev_to_name(__entry->dev), __entry->tid, > > + ftrace_print_bdevname(p, __entry->dev), __entry->tid, > > jiffies_to_msecs(__entry->wait), > > jiffies_to_msecs(__entry->running), > > jiffies_to_msecs(__entry->locked), > > @@ -194,7 +195,7 @@ TRACE_EVENT(jbd2_checkpoint_stats, > > > > TP_printk("dev %s tid %lu chp_time %u forced_to_close %u " > > "written %u dropped %u", > > - jbd2_dev_to_name(__entry->dev), __entry->tid, > > + ftrace_print_bdevname(p, __entry->dev), __entry->tid, > > jiffies_to_msecs(__entry->chp_time), > > __entry->forced_to_close, __entry->written, __entry->dropped) > > ); > > @@ -223,7 +224,7 @@ TRACE_EVENT(jbd2_cleanup_journal_tail, > > ), > > > > TP_printk("dev %s from %u to %u offset %lu freed %lu", > > - jbd2_dev_to_name(__entry->dev), __entry->tail_sequence, > > + ftrace_print_bdevname(p, __entry->dev), __entry->tail_sequence, > > __entry->first_tid, __entry->block_nr, __entry->freed) > > ); > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 1c45b6a..c37597a 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -2427,11 +2427,8 @@ static void __exit journal_exit(void) * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 * tracing infrastructure to map a dev_t to a device name. * - * The caller should use rcu_read_lock() in order to make sure the - * device name stays valid until its done with it. We use - * rcu_read_lock() as well to make sure we're safe in case the caller - * gets sloppy, and because rcu_read_lock() is cheap and can be safely - * nested. + * We use caches to cache the results and use rcu_read_lock() + * to protect the caches. */ struct devname_cache { struct rcu_head rcu; @@ -2442,34 +2439,35 @@ struct devname_cache { static struct devname_cache __rcu *devcache[1 << CACHE_SIZE_BITS]; static DEFINE_SPINLOCK(devname_cache_lock); -const char *jbd2_dev_to_name(dev_t device) +void jbd2_dev_to_name(dev_t device, char *devname) { int i = hash_32(device, CACHE_SIZE_BITS); - char *ret; struct block_device *bd; static struct devname_cache *cache; rcu_read_lock(); cache = rcu_dereference(devcache[i]); if (cache && cache->device == device) { - ret = cache->devname; + memcpy(devname, cache->devname, BDEVNAME_SIZE); rcu_read_unlock(); - return ret; + return; } rcu_read_unlock(); cache = kmalloc(sizeof(struct devname_cache), GFP_KERNEL); - if (!cache) - return "NODEV-ALLOCFAILURE"; /* Something non-NULL */ + if (!cache) { + __bdevname(device, devname); + return; + } bd = bdget(device); spin_lock(&devname_cache_lock); if (devcache[i]) { if (devcache[i]->device == device) { kfree(cache); bdput(bd); - ret = devcache[i]->devname; + memcpy(devname, devcache[i]->devname, BDEVNAME_SIZE); spin_unlock(&devname_cache_lock); - return ret; + return; } kfree_rcu(devcache[i], rcu); } @@ -2480,9 +2478,8 @@ const char *jbd2_dev_to_name(dev_t device) } else __bdevname(device, cache->devname); rcu_assign_pointer(devcache[i], cache); - ret = cache->devname; + memcpy(devname, cache->devname, BDEVNAME_SIZE); spin_unlock(&devname_cache_lock); - return ret; } EXPORT_SYMBOL(jbd2_dev_to_name); diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 59d3ef1..2959ead 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -6,6 +6,7 @@ #include <linux/percpu.h> #include <linux/hardirq.h> #include <linux/perf_event.h> +#include <linux/jbd2.h> struct trace_array; struct tracer; @@ -28,6 +29,15 @@ const char *ftrace_print_flags_seq(struct trace_seq *p, const char *delim, const char *ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val, const struct trace_print_flags *symbol_array); +static inline const char *ftrace_print_bdevname(struct trace_seq *p, dev_t device) +{ + char *bdevname = trace_seq_reserve(p, BDEVNAME_SIZE); + + jbd2_dev_to_name(device, bdevname); + + return bdevname; +} + #if BITS_PER_LONG == 32 const char *ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val, diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 4ecb7b1..964f375 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1331,11 +1331,11 @@ extern int jbd_blocks_per_page(struct inode *inode); #define BUFFER_TRACE2(bh, bh2, info) do {} while (0) #define JBUFFER_TRACE(jh, info) do {} while (0) -/* - * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 +/* + * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 * tracing infrastructure to map a dev_t to a device name. */ -extern const char *jbd2_dev_to_name(dev_t device); +extern void jbd2_dev_to_name(dev_t device, char *bdevname); #endif /* __KERNEL__ */ diff --git a/include/trace/events/jbd2.h b/include/trace/events/jbd2.h index bf16545..a9c8b44 100644 --- a/include/trace/events/jbd2.h +++ b/include/trace/events/jbd2.h @@ -27,7 +27,7 @@ TRACE_EVENT(jbd2_checkpoint, ), TP_printk("dev %s result %d", - jbd2_dev_to_name(__entry->dev), __entry->result) + ftrace_print_bdevname(p, __entry->dev), __entry->result) ); DECLARE_EVENT_CLASS(jbd2_commit, @@ -49,7 +49,7 @@ DECLARE_EVENT_CLASS(jbd2_commit, ), TP_printk("dev %s transaction %d sync %d", - jbd2_dev_to_name(__entry->dev), __entry->transaction, + ftrace_print_bdevname(p, __entry->dev), __entry->transaction, __entry->sync_commit) ); @@ -101,7 +101,7 @@ TRACE_EVENT(jbd2_end_commit, ), TP_printk("dev %s transaction %d sync %d head %d", - jbd2_dev_to_name(__entry->dev), __entry->transaction, + ftrace_print_bdevname(p, __entry->dev), __entry->transaction, __entry->sync_commit, __entry->head) ); @@ -121,7 +121,8 @@ TRACE_EVENT(jbd2_submit_inode_data, ), TP_printk("dev %s ino %lu", - jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino) + ftrace_print_bdevname(p, __entry->dev), + (unsigned long) __entry->ino) ); TRACE_EVENT(jbd2_run_stats, @@ -158,7 +159,7 @@ TRACE_EVENT(jbd2_run_stats, TP_printk("dev %s tid %lu wait %u running %u locked %u flushing %u " "logging %u handle_count %u blocks %u blocks_logged %u", - jbd2_dev_to_name(__entry->dev), __entry->tid, + ftrace_print_bdevname(p, __entry->dev), __entry->tid, jiffies_to_msecs(__entry->wait), jiffies_to_msecs(__entry->running), jiffies_to_msecs(__entry->locked), @@ -194,7 +195,7 @@ TRACE_EVENT(jbd2_checkpoint_stats, TP_printk("dev %s tid %lu chp_time %u forced_to_close %u " "written %u dropped %u", - jbd2_dev_to_name(__entry->dev), __entry->tid, + ftrace_print_bdevname(p, __entry->dev), __entry->tid, jiffies_to_msecs(__entry->chp_time), __entry->forced_to_close, __entry->written, __entry->dropped) ); @@ -223,7 +224,7 @@ TRACE_EVENT(jbd2_cleanup_journal_tail, ), TP_printk("dev %s from %u to %u offset %lu freed %lu", - jbd2_dev_to_name(__entry->dev), __entry->tail_sequence, + ftrace_print_bdevname(p, __entry->dev), __entry->tail_sequence, __entry->first_tid, __entry->block_nr, __entry->freed) );
TP_printk() is not inside the RCU critical section, so the return value of jbd2_dev_to_name() may be invalid. This fix pass a devname argument to store the result name to void this problem. And ftrace_print_bdevname() is introduced to wrap trace_seq_reserve() and jbd2_dev_to_name(). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> --- fs/jbd2/journal.c | 27 ++++++++++++--------------- include/linux/ftrace_event.h | 10 ++++++++++ include/linux/jbd2.h | 6 +++--- include/trace/events/jbd2.h | 15 ++++++++------- 4 files changed, 33 insertions(+), 25 deletions(-)