On Wed, May 29, 2024 at 01:19:55AM +0000, Harshad Shirwadkar wrote: > If the inode that's being requested to track using ext4_fc_track_inode > is being committed, then wait until the inode finishes the > commit. Also, add calls to ext4_fc_track_inode at the right places. > > With this patch, now calling ext4_reserve_inode_write() results in > inode being tracked for next fast commit. A subtle lock ordering > requirement with i_data_sem (which is documented in the code) requires > that ext4_fc_track_inode() be called before grabbing i_data_sem. So, > this patch also adds explicit ext4_fc_track_inode() calls in places > where i_data_sem grabbed. > > Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx> I tried applying this patchset to both the current ext4/dev branch as well as on to 6.10-rc5, and generic/241 is triggering large series of WARNINGS followed by a BUG (or in some cases, a soft lockup). A bisection leads me to this patch. The WARN stack trace: [ 4.061189] ------------[ cut here ]------------ [ 4.061848] WARNING: CPU: 1 PID: 2627 at fs/ext4/fast_commit.c:259 ext4_fc_del+0x7d/0x190 [ 4.062919] CPU: 1 PID: 2627 Comm: dbench Not tainted 6.10.0-rc5-xfstests-00033-gb6f5b0076b56 #350 [ 4.064070] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 4.065077] RIP: 0010:ext4_fc_del+0x7d/0x190 [ 4.065404] Code: 0f 84 f0 00 00 00 48 8b 83 48 ff ff ff 48 0f ba e0 2a 73 18 48 8b 43 28 48 8b 80 90 03 00 00 48 8b 80 80 00 00 00 a8 02 75 02 <0f> 0b 48 89 ef e8 09 ad 68 00 84 c0 74 0f 48 8b 53 98 48 8b 43 a0 [ 4.066190] RSP: 0018:ffffc90003707d98 EFLAGS: 00010246 [ 4.066415] RAX: 0000000000000001 RBX: ffff888013de5c08 RCX: 0000000000000000 [ 4.066718] RDX: 0000000000000001 RSI: 00000000ffffffff RDI: ffff88800a22c7f0 [ 4.067019] RBP: ffff888013de5ba0 R08: ffffffff827fc6fe R09: ffff888008bed000 [ 4.067323] R10: 0000000000000008 R11: 000000000000001e R12: ffff88800a22c7f0 [ 4.067629] R13: ffff88800a22c000 R14: ffff888013de5b90 R15: ffff88800ac0c000 [ 4.067935] FS: 00007fec79a4e740(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000 [ 4.068281] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 4.068530] CR2: 000055d2f34b87e8 CR3: 000000000f492003 CR4: 0000000000770ef0 [ 4.068834] PKRU: 55555554 [ 4.068952] Call Trace: [ 4.069061] <TASK> [ 4.069158] ? __warn+0x7b/0x120 [ 4.069338] ? ext4_fc_del+0x7d/0x190 [ 4.069497] ? report_bug+0x174/0x1c0 [ 4.069655] ? handle_bug+0x3a/0x70 [ 4.069809] ? exc_invalid_op+0x17/0x70 [ 4.069975] ? asm_exc_invalid_op+0x1a/0x20 [ 4.070156] ? ext4_fc_del+0x7d/0x190 [ 4.070309] ? ext4_fc_del+0x44/0x190 [ 4.070468] ext4_clear_inode+0x12/0xb0 [ 4.070636] ext4_free_inode+0x86/0x5a0 [ 4.070802] ext4_evict_inode+0x457/0x6b0 [ 4.070976] evict+0xcd/0x1d0 [ 4.071114] do_unlinkat+0x2de/0x330 [ 4.071271] __x64_sys_unlink+0x23/0x30 [ 4.071436] do_syscall_64+0x4b/0x110 [ 4.071596] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 4.071812] RIP: 0033:0x7fec79b4aa07 [ 4.071969] Code: f0 ff ff 73 01 c3 48 8b 0d f6 83 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c9 83 0d 00 f7 d8 64 89 01 48 [ 4.072760] RSP: 002b:00007ffed55de918 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 [ 4.073081] RAX: ffffffffffffffda RBX: 00007ffed55dedb0 RCX: 00007fec79b4aa07 [ 4.073429] RDX: 0000000000000000 RSI: 00007ffed55dedb0 RDI: 00007ffed55dedb0 [ 4.073733] RBP: 000055d2f34a37f0 R08: 0fffffffffffffff R09: 0000000000000000 [ 4.074033] R10: 0000000000000000 R11: 0000000000000206 R12: 000055d2f34a35d0 [ 4.074338] R13: 00007fec79c35000 R14: 0000000000000004 R15: 00007fec79c35050 [ 4.074650] </TASK> [ 4.074747] ---[ end trace 0000000000000000 ]--- And here's the BUG: [ 5.121989] BUG: kernel NULL pointer dereference, address: 00000000000000b8 [ 5.122281] #PF: supervisor read access in kernel mode [ 5.122500] #PF: error_code(0x0000) - not-present page [ 5.122717] PGD 0 P4D 0 [ 5.122828] Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI [ 5.123036] CPU: 0 PID: 2629 Comm: dbench Tainted: G W 6.10.0-rc5-xfstests-00033-gb6f5b0076b56 #350 [ 5.123470] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 5.123857] RIP: 0010:ext4_fc_perform_commit+0x303/0x4b0 [ 5.124082] Code: fd 48 2d a0 00 00 00 48 39 d3 75 af e9 ac fe ff ff 49 8b 4d 58 49 8d 45 58 48 39 c1 0f 84 9f 01 00 00 49 8b 45 58 49 63 4d 08 <48> 39 88 b8 00 00 00 4c 8d 78 78 0f 85 7f 01 00 00 48 89 ef e8 c4 [ 5.124855] RSP: 0018:ffffc90003727df8 EFLAGS: 00010246 [ 5.125072] RAX: 0000000000000000 RBX: ffff8880089e5f08 RCX: 00000000089e5f08 [ 5.125416] RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffff88800a22c7f0 [ 5.125712] RBP: ffff88800a22c7f0 R08: ffff88807dc2fbc0 R09: 0000000000000000 [ 5.126009] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88800a22c7c8 [ 5.126310] R13: ffff8880089e5f08 R14: ffff88800a22c7a8 R15: ffff88800a22c708 [ 5.126609] FS: 00007fec79a4e740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 [ 5.126943] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5.127188] CR2: 00000000000000b8 CR3: 000000000f48e002 CR4: 0000000000770ef0 [ 5.127483] PKRU: 55555554 [ 5.127598] Call Trace: [ 5.127705] <TASK> [ 5.127838] ? __die+0x23/0x60 [ 5.127973] ? page_fault_oops+0xa3/0x160 [ 5.128143] ? exc_page_fault+0x6a/0x160 [ 5.128351] ? asm_exc_page_fault+0x26/0x30 [ 5.128530] ? ext4_fc_perform_commit+0x303/0x4b0 [ 5.128728] ? ext4_fc_perform_commit+0x36b/0x4b0 [ 5.128948] ext4_fc_commit+0x17f/0x300 [ 5.129116] ext4_sync_file+0x1ce/0x380 [ 5.129310] __x64_sys_fsync+0x3b/0x70 [ 5.129470] do_syscall_64+0x4b/0x110 [ 5.129627] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 5.129840] RIP: 0033:0x7fec79b4fb10 [ 5.129995] Code: 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 80 3d d1 ba 0d 00 00 74 17 b8 4a 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c [ 5.130764] RSP: 002b:00007ffed55de948 EFLAGS: 00000202 ORIG_RAX: 000000000000004a [ 5.131079] RAX: ffffffffffffffda RBX: 00007fec79c35450 RCX: 00007fec79b4fb10 [ 5.131381] RDX: 0000000000002b6f RSI: 0000000000002b6f RDI: 0000000000000005 [ 5.131681] RBP: 000055d2f34a3660 R08: 1999999999999999 R09: 0000000000000000 [ 5.131981] R10: 00007fec79bcdac0 R11: 0000000000000202 R12: 000055d2f34a35d0 [ 5.132280] R13: 00007fec79c35450 R14: 0000000000000003 R15: 00007fec79c354a0 [ 5.132575] </TASK> [ 5.132670] CR2: 00000000000000b8 [ 5.132812] ---[ end trace 0000000000000000 ]--- Harshad, can you take a look? Thanks! - Ted
