https://bugzilla.kernel.org/show_bug.cgi?id=208565
Bug ID: 208565 Summary: There may be dead lock for cp_rwsem during checkpoint Product: File System Version: 2.5 Kernel Version: 4.14.181 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: high Priority: P1 Component: f2fs Assignee: filesystem_f...@kernel-bugs.kernel.org Reporter: zhiguo....@unisoc.com Regression: No A deadlock may happens in the following scenario, backtrace is: PID: 257 TASK: ecdd0000 CPU: 0 COMMAND: "init" #0 [<c0b420ec>] (__schedule) from [<c0b423c8>] #1 [<c0b423c8>] (schedule) from [<c0b459d4>] #2 [<c0b459d4>] (rwsem_down_read_failed) from [<c0b44fa0>] #3 [<c0b44fa0>] (down_read) from [<c044233c>] #4 [<c044233c>] (f2fs_truncate_blocks) from [<c0442890>] #5 [<c0442890>] (f2fs_truncate) from [<c044d408>] #6 [<c044d408>] (f2fs_evict_inode) from [<c030be18>] #7 [<c030be18>] (evict) from [<c030a558>] #8 [<c030a558>] (iput) from [<c047c600>] #9 [<c047c600>] (f2fs_sync_node_pages) from [<c0465414>] #10 [<c0465414>] (f2fs_write_checkpoint) from [<c04575f4>] #11 [<c04575f4>] (f2fs_sync_fs) from [<c0441918>] #12 [<c0441918>] (f2fs_do_sync_file) from [<c0441098>] #13 [<c0441098>] (f2fs_sync_file) from [<c0323fa0>] #14 [<c0323fa0>] (vfs_fsync_range) from [<c0324294>] #15 [<c0324294>] (do_fsync) from [<c0324014>] #16 [<c0324014>] (sys_fsync) from [<c0108bc0>] f2fs_sync_node_pages tries to flush dirty inode and calls iput(). This results in deadlock as iput() tries to hold cp_rwsem, which is already held at the beginning by checkpoint->block_operations(). There is a similar issue and patch in android.googlesource.com with commit id is 82cc5e607b56abea4ea77023650247f5ae41b515, but the call trace is: - f2fs_sync_node_pages() - if (is_inline_node(page)) > - flush_inline_data() - ilookup() page = f2fs_pagecache_get_page() if (!page) goto iput_out; iput_out: -close() -iput() iput(inode); - f2fs_evict_inode() - f2fs_truncate_blocks() - f2fs_lock_op() - down_read(&sbi->cp_rwsem); it seems than this patch has not cover current deadlock scenario, the current deadlock call trace is: - f2fs_sync_node_pages() > - if (flush_dirty_inode(page)) - iput(inode); - f2fs_evict_inode() - f2fs_truncate_blocks() - f2fs_lock_op() - down_read(&sbi->cp_rwsem); please help check and confirm. thanks! -- You are receiving this mail because: You are watching the assignee of the bug. _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel