Hi, i enabled KCSAN for Linux 6.6.19 on Raspberry Pi 3 B+ (arm64/defconfig) and after installing a Debian packaging on the ext4 rootfs the following has been triggered in the kernel log: [ 1389.056656] ================================================================== [ 1389.056781] BUG: KCSAN: data-race in ext4_da_write_end / mpage_process_page_bufs [ 1389.056926] write to 0xffff29ba65896a68 of 8 bytes by task 1447 on cpu 1: [ 1389.056989] ext4_da_write_end+0xe4/0x43c [ 1389.057058] generic_perform_write+0x1c0/0x2dc [ 1389.057161] ext4_buffered_write_iter+0x90/0x198 [ 1389.057246] ext4_file_write_iter+0x98/0x84c [ 1389.057328] vfs_write+0x374/0x4bc [ 1389.057398] ksys_write+0x84/0x138 [ 1389.057467] __arm64_sys_write+0x44/0x58 [ 1389.057539] invoke_syscall+0x60/0x180 [ 1389.057636] el0_svc_common.constprop.0+0x78/0x14c [ 1389.057735] do_el0_svc+0x34/0x44 [ 1389.057827] el0_svc+0x38/0x70 [ 1389.057914] el0t_64_sync_handler+0x13c/0x158 [ 1389.058007] el0t_64_sync+0x190/0x194 [ 1389.058109] read to 0xffff29ba65896a68 of 8 bytes by task 939 on cpu 0: [ 1389.058172] mpage_process_page_bufs+0x54/0x308 [ 1389.058268] mpage_prepare_extent_to_map+0x670/0x81c [ 1389.058337] ext4_do_writepages+0x5bc/0xf78 [ 1389.058405] ext4_writepages+0xf4/0x1a4 [ 1389.058471] do_writepages+0xb8/0x294 [ 1389.058557] __writeback_single_inode+0x54/0x270 [ 1389.058628] writeback_sb_inodes+0x374/0x6ac [ 1389.058697] __writeback_inodes_wb+0x68/0x150 [ 1389.058767] wb_writeback.isra.0+0x228/0x258 [ 1389.058837] wb_workfn+0x3e4/0x618 [ 1389.058904] process_one_work+0x314/0x53c [ 1389.058993] worker_thread+0x628/0x7e4 [ 1389.059080] kthread+0x1c0/0x1c4 [ 1389.059156] ret_from_fork+0x10/0x20 [ 1389.059262] value changed: 0x0000000002a34000 -> 0x0000000002a35000 [ 1389.059347] Reported by Kernel Concurrency Sanitizer on: [ 1389.059390] CPU: 0 PID: 939 Comm: kworker/u8:1 Not tainted 6.6.19 #2 [ 1389.059466] Hardware name: Raspberry Pi 3 Model B Plus Rev 1.3 (DT) [ 1389.059519] Workqueue: writeback wb_workfn (flush-179:0) [ 1389.059631] ================================================================== I hope this isn't a false positive and helpful. Regards
