Messages in this thread | | | Subject | Re: [PATCH] f2fs: do not use mutex lock in atomic context | From | Chao Yu <> | Date | Wed, 13 Feb 2019 11:25:31 +0800 |
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On 2019/2/4 16:06, Sahitya Tummala wrote: > Fix below warning coming because of using mutex lock in atomic context. > > BUG: sleeping function called from invalid context at kernel/locking/mutex.c:98 > in_atomic(): 1, irqs_disabled(): 0, pid: 585, name: sh > Preemption disabled at: __radix_tree_preload+0x28/0x130 > Call trace: > dump_backtrace+0x0/0x2b4 > show_stack+0x20/0x28 > dump_stack+0xa8/0xe0 > ___might_sleep+0x144/0x194 > __might_sleep+0x58/0x8c > mutex_lock+0x2c/0x48 > f2fs_trace_pid+0x88/0x14c > f2fs_set_node_page_dirty+0xd0/0x184 > > Do not use f2fs_radix_tree_insert() to avoid doing cond_resched() with > spin_lock() acquired. > > Signed-off-by: Sahitya Tummala <stummala@codeaurora.org> > --- > fs/f2fs/trace.c | 20 +++++++++++++------- > 1 file changed, 13 insertions(+), 7 deletions(-) > > diff --git a/fs/f2fs/trace.c b/fs/f2fs/trace.c > index ce2a5eb..d0ab533 100644 > --- a/fs/f2fs/trace.c > +++ b/fs/f2fs/trace.c > @@ -14,7 +14,7 @@ > #include "trace.h" > > static RADIX_TREE(pids, GFP_ATOMIC); > -static struct mutex pids_lock; > +static spinlock_t pids_lock; > static struct last_io_info last_io; > > static inline void __print_last_io(void) > @@ -58,23 +58,29 @@ void f2fs_trace_pid(struct page *page) > > set_page_private(page, (unsigned long)pid); > > +retry: > if (radix_tree_preload(GFP_NOFS)) > return; > > - mutex_lock(&pids_lock); > + spin_lock(&pids_lock); > p = radix_tree_lookup(&pids, pid); > if (p == current) > goto out; > if (p) > radix_tree_delete(&pids, pid); > > - f2fs_radix_tree_insert(&pids, pid, current); > + if (radix_tree_insert(&pids, pid, current)) { > + spin_unlock(&pids_lock); > + radix_tree_preload_end(); > + cond_resched(); > + goto retry; > + } > > trace_printk("%3x:%3x %4x %-16s\n", > MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev), > pid, current->comm);
Hi Sahitya,
Can trace_printk sleep? For safety, how about moving it out of spinlock?
Thanks,
> out: > - mutex_unlock(&pids_lock); > + spin_unlock(&pids_lock); > radix_tree_preload_end(); > } > > @@ -119,7 +125,7 @@ void f2fs_trace_ios(struct f2fs_io_info *fio, int flush) > > void f2fs_build_trace_ios(void) > { > - mutex_init(&pids_lock); > + spin_lock_init(&pids_lock); > } > > #define PIDVEC_SIZE 128 > @@ -147,7 +153,7 @@ void f2fs_destroy_trace_ios(void) > pid_t next_pid = 0; > unsigned int found; > > - mutex_lock(&pids_lock); > + spin_lock(&pids_lock); > while ((found = gang_lookup_pids(pid, next_pid, PIDVEC_SIZE))) { > unsigned idx; > > @@ -155,5 +161,5 @@ void f2fs_destroy_trace_ios(void) > for (idx = 0; idx < found; idx++) > radix_tree_delete(&pids, pid[idx]); > } > - mutex_unlock(&pids_lock); > + spin_unlock(&pids_lock); > } >
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