-
Jaegeuk Kim authored
This patch should resolve the following bug. ========================================================= [ INFO: possible irq lock inversion dependency detected ] 3.13.0-rc5.f2fs+ #6 Not tainted --------------------------------------------------------- kswapd0/41 just changed the state of lock: (&sbi->gc_mutex){+.+.-.}, at: [<ffffffffa030503e>] f2fs_balance_fs+0xae/0xd0 [f2fs] but this lock took another, RECLAIM_FS-READ-unsafe lock in the past: (&sbi->cp_rwsem){++++.?} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Chain exists of: &sbi->gc_mutex --> &sbi->cp_mutex --> &sbi->cp_rwsem Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sbi->cp_rwsem); local_irq_disable(); lock(&sbi->gc_mutex); lock(&sbi->cp_mutex); <Interrupt> lock(&sbi->gc_mutex); *** DEADLOCK *** This bug is due to the f2fs_balance_fs call in f2fs_write_data_page. If f2fs_write_data_page is triggered by wbc->for_reclaim via kswapd, it should not call f2fs_balance_fs which tries to get a mutex grabbed by original syscall flow. Signed-off-by:
Jaegeuk Kim <jaegeuk.kim@samsung.com>
c33ec326