| Message ID | c79f9ff1-e451-d2b4-a800-738053e47df8@jp.fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: ctree.h: Fix suspicious rcu usage warning in btrfs_debug_in_rcu() | expand |
On Fri, Aug 24, 2018 at 11:35:28AM +0900, Misono Tomohiro wrote: > commit 672d599041c8 ("btrfs: Use wrapper macro for rcu string to remove > duplicate code") replaces some open coded rcu string handling with macro. > > It turns out that btrfs_debug_in_rcu() is used for the first time and > the macro lacks lock/unlock of rcu string for non debug case > (i.e. when message is not printed), leading suspicious RCU usage warning > when CONFIG_PROVE_RCU is on. > > Fix this by adding a wrapper to call lock/unlock for non debug case too. > > Fixes: 672d599041c8 ("btrfs: Use wrapper macro for rcu string to remove > duplicate code") > Reported-by: David Howells <dhowells@redhat.com> > Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Thanks, I'll add it to the 4.19 queue, expected to appear in rc2.
Misono Tomohiro <misono.tomohiro@jp.fujitsu.com> wrote: > commit 672d599041c8 ("btrfs: Use wrapper macro for rcu string to remove > duplicate code") replaces some open coded rcu string handling with macro. > > It turns out that btrfs_debug_in_rcu() is used for the first time and > the macro lacks lock/unlock of rcu string for non debug case > (i.e. when message is not printed), leading suspicious RCU usage warning > when CONFIG_PROVE_RCU is on. > > Fix this by adding a wrapper to call lock/unlock for non debug case too. > > Fixes: 672d599041c8 ("btrfs: Use wrapper macro for rcu string to remove > duplicate code") > Reported-by: David Howells <dhowells@redhat.com> > Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com> Tested-by: David Howells <dhowells@redhat.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 53af9f5253f4..cc8b4ff8dcea 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3390,9 +3390,9 @@ do { \ #define btrfs_debug(fs_info, fmt, args...) \ btrfs_no_printk(fs_info, KERN_DEBUG fmt, ##args) #define btrfs_debug_in_rcu(fs_info, fmt, args...) \ - btrfs_no_printk(fs_info, KERN_DEBUG fmt, ##args) + btrfs_no_printk_in_rcu(fs_info, KERN_DEBUG fmt, ##args) #define btrfs_debug_rl_in_rcu(fs_info, fmt, args...) \ - btrfs_no_printk(fs_info, KERN_DEBUG fmt, ##args) + btrfs_no_printk_in_rcu(fs_info, KERN_DEBUG fmt, ##args) #define btrfs_debug_rl(fs_info, fmt, args...) \ btrfs_no_printk(fs_info, KERN_DEBUG fmt, ##args) #endif @@ -3404,6 +3404,13 @@ do { \ rcu_read_unlock(); \ } while (0) +#define btrfs_no_printk_in_rcu(fs_info, fmt, args...) \ +do { \ + rcu_read_lock(); \ + btrfs_no_printk(fs_info, fmt, ##args); \ + rcu_read_unlock(); \ +} while (0) + #define btrfs_printk_ratelimited(fs_info, fmt, args...) \ do { \ static DEFINE_RATELIMIT_STATE(_rs, \
commit 672d599041c8 ("btrfs: Use wrapper macro for rcu string to remove duplicate code") replaces some open coded rcu string handling with macro. It turns out that btrfs_debug_in_rcu() is used for the first time and the macro lacks lock/unlock of rcu string for non debug case (i.e. when message is not printed), leading suspicious RCU usage warning when CONFIG_PROVE_RCU is on. Fix this by adding a wrapper to call lock/unlock for non debug case too. Fixes: 672d599041c8 ("btrfs: Use wrapper macro for rcu string to remove duplicate code") Reported-by: David Howells <dhowells@redhat.com> Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com> --- fs/btrfs/ctree.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)