Got that at a hardened Gentoo Linux server with 4.12.0 (for the first time) at a BTRFS logical volume occuping about 4/9 of a 5 TB volume group after an uptime of about 2 days : Had issues with processes accessing files at that volume now too.
Jul 6 15:33:53 mr-fox kernel: [158695.417132] ================================================================================ Jul 6 15:33:53 mr-fox kernel: [158695.417137] UBSAN: Undefined behaviour in fs/fs-writeback.c:1586:18 Jul 6 15:33:53 mr-fox kernel: [158695.417139] signed integer overflow: Jul 6 15:33:53 mr-fox kernel: [158695.417140] 9223372036854775807 - -327 cannot be represented in type 'long int' Jul 6 15:33:53 mr-fox kernel: [158695.417143] CPU: 9 PID: 20027 Comm: kworker/u24:16 Not tainted 4.12.0 #1 Jul 6 15:33:53 mr-fox kernel: [158695.417144] Hardware name: /DX79TO, BIOS SIX7910J.86A.0650.2014.0307.0138 03/07/2014 Jul 6 15:33:53 mr-fox kernel: [158695.417151] Workqueue: writeback wb_workfn (flush-btrfs-1) Jul 6 15:33:53 mr-fox kernel: [158695.417153] Call Trace: Jul 6 15:33:53 mr-fox kernel: [158695.417158] dump_stack+0x60/0x9a Jul 6 15:33:53 mr-fox kernel: [158695.417161] ubsan_epilogue+0xd/0x40 Jul 6 15:33:53 mr-fox kernel: [158695.417163] handle_overflow+0xc8/0xf0 Jul 6 15:33:53 mr-fox kernel: [158695.417165] ? __writeback_single_inode+0x17c/0x560 Jul 6 15:33:53 mr-fox kernel: [158695.417167] __ubsan_handle_sub_overflow+0xe/0x10 Jul 6 15:33:53 mr-fox kernel: [158695.417169] writeback_sb_inodes+0x7a3/0x850 Jul 6 15:33:53 mr-fox kernel: [158695.417171] __writeback_inodes_wb+0xa0/0x140 Jul 6 15:33:53 mr-fox kernel: [158695.417172] wb_writeback+0x35c/0x4d0 Jul 6 15:33:53 mr-fox kernel: [158695.417174] wb_workfn+0x25b/0x6b0 Jul 6 15:33:53 mr-fox kernel: [158695.417175] ? wb_workfn+0x25b/0x6b0 Jul 6 15:33:53 mr-fox kernel: [158695.417178] process_one_work+0x225/0x7d0 Jul 6 15:33:53 mr-fox kernel: [158695.417180] worker_thread+0x6b/0x500 Jul 6 15:33:53 mr-fox kernel: [158695.417182] kthread+0x168/0x240 Jul 6 15:33:53 mr-fox kernel: [158695.417184] ? process_one_work+0x7d0/0x7d0 Jul 6 15:33:53 mr-fox kernel: [158695.417185] ? __kthread_create_on_node+0x1c0/0x1c0 Jul 6 15:33:53 mr-fox kernel: [158695.417189] ret_from_fork+0x22/0x30 Jul 6 15:33:53 mr-fox kernel: [158695.417190] ================================================================================ Jul 6 15:33:53 mr-fox kernel: [158695.417193] ================================================================================ Jul 6 15:33:53 mr-fox kernel: [158695.417194] UBSAN: Undefined behaviour in fs/fs-writeback.c:1797:9 Jul 6 15:33:53 mr-fox kernel: [158695.417195] signed integer overflow: Jul 6 15:33:53 mr-fox kernel: [158695.417196] 9223372036854775807 - -9223372036854775482 cannot be represented in type 'long int' Jul 6 15:33:53 mr-fox kernel: [158695.417198] CPU: 9 PID: 20027 Comm: kworker/u24:16 Not tainted 4.12.0 #1 Jul 6 15:33:53 mr-fox kernel: [158695.417199] Hardware name: /DX79TO, BIOS SIX7910J.86A.0650.2014.0307.0138 03/07/2014 Jul 6 15:33:53 mr-fox kernel: [158695.417201] Workqueue: writeback wb_workfn (flush-btrfs-1) Jul 6 15:33:53 mr-fox kernel: [158695.417203] Call Trace: Jul 6 15:33:53 mr-fox kernel: [158695.417204] dump_stack+0x60/0x9a Jul 6 15:33:53 mr-fox kernel: [158695.417206] ubsan_epilogue+0xd/0x40 Jul 6 15:33:53 mr-fox kernel: [158695.417208] handle_overflow+0xc8/0xf0 Jul 6 15:33:53 mr-fox kernel: [158695.417210] __ubsan_handle_sub_overflow+0xe/0x10 Jul 6 15:33:53 mr-fox kernel: [158695.417211] wb_writeback+0x3a7/0x4d0 Jul 6 15:33:53 mr-fox kernel: [158695.417213] wb_workfn+0x25b/0x6b0 Jul 6 15:33:53 mr-fox kernel: [158695.417214] ? wb_workfn+0x25b/0x6b0 Jul 6 15:33:53 mr-fox kernel: [158695.417216] process_one_work+0x225/0x7d0 Jul 6 15:33:53 mr-fox kernel: [158695.417218] worker_thread+0x6b/0x500 Jul 6 15:33:53 mr-fox kernel: [158695.417219] kthread+0x168/0x240 Jul 6 15:33:53 mr-fox kernel: [158695.417221] ? process_one_work+0x7d0/0x7d0 Jul 6 15:33:53 mr-fox kernel: [158695.417222] ? __kthread_create_on_node+0x1c0/0x1c0 Jul 6 15:33:53 mr-fox kernel: [158695.417224] ret_from_fork+0x22/0x30 Jul 6 15:33:53 mr-fox kernel: [158695.417225] ================================================================================ -- Toralf PGP C4EACDDE 0076E94E
