[BUG?] invalidate_lock not held in read_cache_folio()

[Dev Jain]

Hi,

My understanding is that there are two ways we are serializing against concurrent
addition of a folio into the pagecache (see 730633f0b7f9).

The kerneldoc of read_cache_folio() says:

"Context: May sleep.  Expects mapping->invalidate_lock to be held."

I put the following in __filemap_add_folio():

+       BUG_ON(!inode_is_locked(mapping->host) &&
+              !rwsem_is_locked(&mapping->invalidate_lock));


And got the following trace:


[    0.088725] kernel BUG at mm/filemap.c:858!
[    0.088727] Internal error: Oops - BUG: 00000000f2000800 [#1]  SMP
[    0.111312] Modules linked in:
[    0.111437] CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 7.1.0-rc5-00493-g65484bf449f7 #178 PREEMPT
[    0.111801] Hardware name: linux,dummy-virt (DT)
[    0.111987] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[    0.112255] pc : __filemap_add_folio+0x5dc/0x680
[    0.112437] lr : __filemap_add_folio+0x168/0x680
[    0.112629] sp : ffff80008005b550
[    0.112757] x29: ffff80008005b5b0 x28: 0000000000100cc0 x27: 00000000ffffffff
[    0.113030] x26: 0000000000000000 x25: 0000000000000001 x24: 0000000000000000
[    0.113312] x23: 0000000000100cc0 x22: ffff0000c2825cc8 x21: 0000000000000000
[    0.113599] x20: fffffdffc30cd700 x19: 0000000000000000 x18: 00000000ffffffff
[    0.113885] x17: 2e33352820736b63 x16: 6f6c62206c616369 x15: ffff80008005b4d0
[    0.114167] x14: 0000000000000000 x13: ffff0000c34a225f x12: 0000000000000000
[    0.114451] x11: 0000000000000000 x10: 000000000000003a x9 : ffffce3993f54940
[    0.114759] x8 : 0000000000000000 x7 : ffff00017f3fc910 x6 : 05ffff0000000001
[    0.115040] x5 : ffff0000c150b000 x4 : ffff80008005b610 x3 : 0000000000100cc0
[    0.115312] x2 : 0000000000000003 x1 : 0000000000000000 x0 : 0000000000000000
[    0.115587] Call trace:
[    0.115686]  __filemap_add_folio+0x5dc/0x680 (P)
[    0.115871]  filemap_add_folio+0xec/0x2d0
[    0.116031]  do_read_cache_folio+0x144/0x2d8
[    0.116194]  read_cache_folio+0x1c/0x30
[    0.116344]  read_part_sector+0x4c/0xf0
[    0.116499]  read_lba+0xb0/0x1a0
[    0.116627]  efi_partition+0xa8/0x740
[    0.116769]  bdev_disk_changed+0x238/0x620
[    0.116939]  blkdev_get_whole+0xac/0x100
[    0.117090]  bdev_open+0x280/0x3c0
[    0.117221]  bdev_file_open_by_dev+0xe4/0x158
[    0.117394]  disk_scan_partitions+0x70/0x160
[    0.117565]  add_disk_fwnode+0x1a4/0x1d0
[    0.117725]  device_add_disk+0x1c/0x30
[    0.117869]  virtblk_probe+0x6a0/0x918
[    0.118025]  virtio_dev_probe+0x1c8/0x310
[    0.118184]  really_probe+0xc4/0x2b0
[    0.118330]  __driver_probe_device+0x88/0x170
[    0.118497]  driver_probe_device+0x44/0x178
[    0.118669]  __driver_attach+0x98/0x1b8
[    0.118819]  bus_for_each_dev+0x84/0xf0
[    0.118979]  driver_attach+0x2c/0x40
[    0.119123]  bus_add_driver+0xec/0x218
[    0.119269]  driver_register+0x64/0x138
[    0.119419]  __register_virtio_driver+0x2c/0x50
[    0.119598]  virtio_blk_init+0x74/0xd0
[    0.119757]  do_one_initcall+0x60/0x3f0
[    0.119903]  kernel_init_freeable+0x1f4/0x540
[    0.120075]  kernel_init+0x2c/0x1f8
[    0.120218]  ret_from_fork+0x10/0x20
[    0.120357] Code: 9401562d d4210000 f9400ec0 b5ffdd20 (d4210000)
[    0.120592] ---[ end trace 0000000000000000 ]---