On Mon, Apr 05, 2021 at 12:19:46PM +0100, Filipe Manana wrote:
> On Sun, Apr 4, 2021 at 5:16 AM Zygo Blaxell
> <ce3g8...@umail.furryterror.org> wrote:
> >
> > Base kernel is 9228ad80f849 "btrfs: zoned: move log tree node allocation
> > out of log_root_tree->log_mutex" from misc-next on 2021-03-29.
> >
> > The BUG() moved, but we are still hitting it:
> >
> > [145427.426011][ T5492] BTRFS info (device dm-0): balance: canceled
> > [145427.689964][ T4811] ------------[ cut here ]------------
> > [145427.692498][ T4811] kernel BUG at fs/btrfs/tree-mod-log.c:675!
> > [145427.694668][ T4811] invalid opcode: 0000 [#1] SMP KASAN PTI
> > [145427.696379][ T4811] CPU: 3 PID: 4811 Comm: crawl_1215 Tainted:
> > G W 5.12.0-7d1efdf501f8-misc-next+ #99
> > [145427.700221][ T4811] Hardware name: QEMU Standard PC (i440FX +
> > PIIX, 1996), BIOS 1.12.0-1 04/01/2014
> > [145427.703623][ T4811] RIP: 0010:tree_mod_log_rewind+0x3b1/0x3c0
> > [145427.706135][ T4811] Code: 05 48 8d 74 10 65 ba 19 00 00 00 e8
> > 49 5e f2 ff e9 a7 fd ff ff 4c 8d 7b 2c 4c 89 ff e8 28 23 b4 ff 48 63 43 2c
> > e9 a2 fe ff ff <0f> 0b 0f 0b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00
> > 00 55 48
> > [145427.713034][ T4811] RSP: 0018:ffffc90001027090 EFLAGS: 00010293
> > [145427.714996][ T4811] RAX: 0000000000000000 RBX: ffff8880a8514600
> > RCX: ffffffffaa9e59b6
> > [145427.717158][ T4811] RDX: 0000000000000007 RSI: dffffc0000000000
> > RDI: ffff8880a851462c
> > [145427.720422][ T4811] RBP: ffffc900010270e0 R08: 00000000000000c0
> > R09: ffffed1004333417
> > [145427.723835][ T4811] R10: ffff88802199a0b7 R11: ffffed1004333416
> > R12: 000000000000000e
> > [145427.727695][ T4811] R13: ffff888135af8748 R14: ffff88818766ff00
> > R15: ffff8880a851462c
> > [145427.731636][ T4811] FS: 00007f29acf62700(0000)
> > GS:ffff8881f2200000(0000) knlGS:0000000000000000
> > [145427.736305][ T4811] CS: 0010 DS: 0000 ES: 0000 CR0:
> > 0000000080050033
> > [145427.739587][ T4811] CR2: 00007f0e6013f718 CR3: 000000010d42e003
> > CR4: 0000000000170ee0
> > [145427.743573][ T4811] Call Trace:
> > [145427.745117][ T4811] btrfs_get_old_root+0x16a/0x5c0
> > [145427.747686][ T4811] ? lock_downgrade+0x400/0x400
> > [145427.754189][ T4811] btrfs_search_old_slot+0x192/0x520
> > [145427.758023][ T4811] ? btrfs_search_slot+0x1090/0x1090
> > [145427.761014][ T4811] ? free_extent_buffer.part.61+0xd7/0x140
> > [145427.765208][ T4811] ? free_extent_buffer+0x13/0x20
> > [145427.770042][ T4811] resolve_indirect_refs+0x3e9/0xfc0
> > [145427.773633][ T4811] ? lock_downgrade+0x400/0x400
> > [145427.777323][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.780539][ T4811] ? add_prelim_ref.part.11+0x150/0x150
> > [145427.785722][ T4811] ? lock_downgrade+0x400/0x400
> > [145427.791086][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.796266][ T4811] ? lock_acquired+0xbb/0x620
> > [145427.798764][ T4811] ? __kasan_check_write+0x14/0x20
> > [145427.801118][ T4811] ? do_raw_spin_unlock+0xa8/0x140
> > [145427.804491][ T4811] ? rb_insert_color+0x340/0x360
> > [145427.808066][ T4811] ? prelim_ref_insert+0x12d/0x430
> > [145427.811889][ T4811] find_parent_nodes+0x5c3/0x1830
> > [145427.815498][ T4811] ? stack_trace_save+0x87/0xb0
> > [145427.819210][ T4811] ? resolve_indirect_refs+0xfc0/0xfc0
> > [145427.823254][ T4811] ? fs_reclaim_acquire+0x67/0xf0
> > [145427.827220][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.829080][ T4811] ? lockdep_hardirqs_on_prepare+0x210/0x210
> > [145427.831237][ T4811] ? fs_reclaim_acquire+0x67/0xf0
> > [145427.835061][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.836508][ T4811] ? ___might_sleep+0x10f/0x1e0
> > [145427.841389][ T4811] ? __kasan_kmalloc+0x9d/0xd0
> > [145427.843054][ T4811] ? trace_hardirqs_on+0x55/0x120
> > [145427.845533][ T4811] btrfs_find_all_roots_safe+0x142/0x1e0
> > [145427.847325][ T4811] ? find_parent_nodes+0x1830/0x1830
> > [145427.849318][ T4811] ? trace_hardirqs_on+0x55/0x120
> > [145427.851210][ T4811] ? ulist_free+0x1f/0x30
> > [145427.852809][ T4811] ? btrfs_inode_flags_to_xflags+0x50/0x50
> > [145427.854654][ T4811] iterate_extent_inodes+0x20e/0x580
> > [145427.856429][ T4811] ? tree_backref_for_extent+0x230/0x230
> > [145427.858552][ T4811] ? release_extent_buffer+0x225/0x280
> > [145427.862789][ T4811] ? read_extent_buffer+0xdd/0x110
> > [145427.865092][ T4811] ? lock_downgrade+0x400/0x400
> > [145427.867069][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.868585][ T4811] ? lock_acquired+0xbb/0x620
> > [145427.872309][ T4811] ? __kasan_check_write+0x14/0x20
> > [145427.873641][ T4811] ? do_raw_spin_unlock+0xa8/0x140
> > [145427.878150][ T4811] ? _raw_spin_unlock+0x22/0x30
> > [145427.879355][ T4811] ? release_extent_buffer+0x225/0x280
> > [145427.881424][ T4811] iterate_inodes_from_logical+0x129/0x170
> > [145427.884711][ T4811] ? iterate_inodes_from_logical+0x129/0x170
> > [145427.888124][ T4811] ? btrfs_inode_flags_to_xflags+0x50/0x50
> > [145427.891553][ T4811] ? iterate_extent_inodes+0x580/0x580
> > [145427.894531][ T4811] ? __vmalloc_node+0x92/0xb0
> > [145427.897439][ T4811] ? init_data_container+0x34/0xb0
> > [145427.900518][ T4811] ? init_data_container+0x34/0xb0
> > [145427.903705][ T4811] ? kvmalloc_node+0x60/0x80
> > [145427.906538][ T4811] btrfs_ioctl_logical_to_ino+0x158/0x230
> > [145427.910125][ T4811] btrfs_ioctl+0x2038/0x4360
> > [145427.912430][ T4811] ? __kasan_check_write+0x14/0x20
> > [145427.914061][ T4811] ? mmput+0x3b/0x220
> > [145427.915380][ T4811] ?
> > btrfs_ioctl_get_supported_features+0x30/0x30
> > [145427.917512][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.919110][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.920845][ T4811] ? lock_release+0xc8/0x650
> > [145427.922227][ T4811] ? __might_fault+0x64/0xd0
> > [145427.923687][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.925222][ T4811] ? lock_downgrade+0x400/0x400
> > [145427.926729][ T4811] ? lockdep_hardirqs_on_prepare+0x210/0x210
> > [145427.928496][ T4811] ? lockdep_hardirqs_on_prepare+0x13/0x210
> > [145427.930396][ T4811] ? _raw_spin_unlock_irqrestore+0x51/0x63
> > [145427.932123][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.933910][ T4811] ? do_vfs_ioctl+0xfc/0x9d0
> > [145427.935664][ T4811] ? ioctl_file_clone+0xe0/0xe0
> > [145427.938147][ T4811] ? lock_downgrade+0x400/0x400
> > [145427.940717][ T4811] ? lockdep_hardirqs_on_prepare+0x210/0x210
> > [145427.943673][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.946249][ T4811] ? lock_release+0xc8/0x650
> > [145427.948509][ T4811] ? __task_pid_nr_ns+0xd3/0x250
> > [145427.950946][ T4811] ? __kasan_check_read+0x11/0x20
> > [145427.953415][ T4811] ? __fget_files+0x160/0x230
> > [145427.955693][ T4811] ? __fget_light+0xf2/0x110
> > [145427.957951][ T4811] __x64_sys_ioctl+0xc3/0x100
> > [145427.961647][ T4811] do_syscall_64+0x37/0x80
> > [145427.963112][ T4811] entry_SYSCALL_64_after_hwframe+0x44/0xae
> > [145427.971975][ T4811] RIP: 0033:0x7f29ae85b427
> > [145427.974101][ T4811] Code: 00 00 90 48 8b 05 69 aa 0c 00 64 c7
> > 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10
> > 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 39 aa 0c 00 f7 d8 64
> > 89 01 48
> > [145427.980483][ T4811] RSP: 002b:00007f29acf5fcf8 EFLAGS: 00000246
> > ORIG_RAX: 0000000000000010
> > [145427.983314][ T4811] RAX: ffffffffffffffda RBX: 00007f29acf5ff40
> > RCX: 00007f29ae85b427
> > [145427.985963][ T4811] RDX: 00007f29acf5ff48 RSI: 00000000c038943b
> > RDI: 0000000000000003
> > [145427.988504][ T4811] RBP: 0000000001000000 R08: 0000000000000000
> > R09: 00007f29acf60120
> > [145427.991085][ T4811] R10: 00005640d5fc7b00 R11: 0000000000000246
> > R12: 0000000000000003
> > [145427.993662][ T4811] R13: 00007f29acf5ff48 R14: 00007f29acf5ff40
> > R15: 00007f29acf5fef8
> > [145427.996289][ T4811] Modules linked in:
> > [145427.997661][ T4811] ---[ end trace 85e5fce078dfbe04 ]---
> >
> > (gdb) l *(tree_mod_log_rewind+0x3b1)
> > 0xffffffff819e5b21 is in tree_mod_log_rewind
> > (fs/btrfs/tree-mod-log.c:675).
> > 670 * the modification. As we're going
> > backwards, we do the
> > 671 * opposite of each operation here.
> > 672 */
> > 673 switch (tm->op) {
> > 674 case BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING:
> > 675 BUG_ON(tm->slot < n);
> > 676 fallthrough;
> > 677 case BTRFS_MOD_LOG_KEY_REMOVE_WHILE_MOVING:
> > 678 case BTRFS_MOD_LOG_KEY_REMOVE:
> > 679 btrfs_set_node_key(eb, &tm->key,
> > tm->slot);
> > (gdb) quit
>
> Ok, there's another similar race to the one previously fixed (missing
> read lock), that I previously missed.
> Can you try the following patch, against misc-next:
>
> https://pastebin.com/raw/MQCCFwhf
>
> Let me know how it goes after that.
> Thanks.
OK so far, but this is only day 3, and these bugs take a week to hit
with my test workload. I'll let you know if anything happens.
>
> --
> Filipe David Manana,
>
> “Whether you think you can, or you think you can't — you're right.”
