On Mon, Oct 18, 2021 at 11:50 AM David Howells <dhowells@xxxxxxxxxx> wrote: > > > Here's a set of patches that rewrites and simplifies the fscache index API > to remove the complex operation scheduling and object state machine in > favour of something much smaller and simpler. It is built on top of the > set of patches that removes the old API[1]. Testing this series in our afs test framework, saw the oops pasted below. cachefiles_begin_operation+0x2d maps to cachefiles/io.c:565, where object is probably NULL (object->file is at offset 0x28). Marc === BUG: kernel NULL pointer dereference, address: 0000000000000028 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 5 PID: 16607 Comm: ar Tainted: G E 5.15.0-rc5.kafs_testing+ #37 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2.fc34 04/01/2014 RIP: 0010:cachefiles_begin_operation+0x2d/0x80 [cachefiles] Code: 00 00 55 53 48 83 ec 08 48 8b 47 08 48 83 7f 10 00 48 8b 68 20 74 0c b8 01 00 00 00 48 83 c4 08 5b 5d c3 48 c7 07 a0 12 1b a0 <48> 8b 45 28 48 89 fb 48 85 c0 74 20 48 8d 7d 04 89 74 24 04 e8 3a RSP: 0018:ffffc90000d33b48 EFLAGS: 00010246 RAX: ffff888014991420 RBX: ffff888100ae9cf0 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff888100ae9cf0 RBP: 0000000000000000 R08: 00000000000006b8 R09: ffff88810e98e000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888014991434 R13: 0000000000000002 R14: ffff888014991420 R15: 0000000000000002 FS: 00007f72d0486b80(0000) GS:ffff888139940000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000028 CR3: 000000007bac8004 CR4: 0000000000770ee0 PKRU: 55555554 Call Trace: fscache_begin_operation.part.0+0x1e3/0x210 [fscache] netfs_write_begin+0x3fb/0x800 [netfs] ? __fscache_use_cookie+0x120/0x200 [fscache] afs_write_begin+0x58/0x2c0 [kafs] ? __vfs_getxattr+0x2a/0x70 generic_perform_write+0xb1/0x1b0 ? file_update_time+0xcf/0x120 __generic_file_write_iter+0x14c/0x1d0 generic_file_write_iter+0x5d/0xb0 afs_file_write+0x73/0xa0 [kafs] new_sync_write+0x105/0x180 vfs_write+0x1cb/0x260 ksys_write+0x4f/0xc0 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f72d059a7a7 Code: 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24 RSP: 002b:00007fffc31942b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f72d059a7a7 RDX: 0000000000000008 RSI: 000055fe42367730 RDI: 0000000000000003 RBP: 000055fe42367730 R08: 0000000000000000 R09: 00007f72d066ca00 R10: 000000000000007c R11: 0000000000000246 R12: 0000000000000008
