On Tue, Dec 28, 2021 at 10:00:53PM +0100, August Wikerfors wrote:
> (resending from gmail due to bounce with outlook)
>
> Hi, I ran into a bug with a very similar call trace, also when copying files
> with rsync from a filesystem mounted using ntfs3. I was able to reproduce it
> on both the default Arch Linux kernel (5.15.11-arch2-1) and on mainline
> 5.16-rc7.
Hi August! This is very helpful; thank you for putting in the work to
figure this out. I am still a little baffled:
> [ 486.361177] RIP: 0010:0xffffff8306d925ff
> [ 486.361192] Code: Unable to access opcode bytes at RIP 0xffffff8306d925d5.
> [ 486.361214] RSP: 0018:ffffaa9ec0f8fb37 EFLAGS: 00010246
> [ 486.361232] RAX: 0000000000000000 RBX: 00000000000002ab RCX: 0000000000000000
> [ 486.361255] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> [ 486.361279] RBP: ffaa9ec0f8fbf800 R08: 0000000000000000 R09: 0000000000000000
> [ 486.361302] R10: 0000000000000000 R11: 0000000000000000 R12: ff99687f5746e000
> [ 486.361324] R13: 00000001112ccaff R14: fffcbb8097368000 R15: 00000000000001ff
> [ 486.361349] ? page_cache_ra_unbounded+0x1c5/0x250
> [ 486.361369] ? filemap_get_pages+0x117/0x730
> [ 486.361386] ? make_kuid+0xf/0x20
> [ 486.361401] ? generic_permission+0x27/0x210
> [ 486.361419] ? walk_component+0x11d/0x1c0
> [ 486.361435] ? filemap_read+0xb9/0x360
> [ 486.361451] ? new_sync_read+0x159/0x1f0
> [ 486.361467] ? vfs_read+0xff/0x1a0
> [ 486.361489] ? ksys_read+0x67/0xf0
> [ 486.361503] ? do_syscall_64+0x5c/0x90
>
> $ scripts/faddr2line vmlinux.5.15.11-arch2-1 page_cache_ra_unbounded+0x1c5/0x250
> page_cache_ra_unbounded+0x1c5/0x250:
> filemap_invalidate_unlock_shared at include/linux/fs.h:853
> (inlined by) page_cache_ra_unbounded at mm/readahead.c:240
So ... Jan added this code in commit 730633f0b7f9, but I don't see how
it could be buggy:
filemap_invalidate_lock_shared(mapping);
... things that don't change mapping ...
filemap_invalidate_unlock_shared(mapping);
and the _unlock_ appears to have a bad pointer. Which makes no sense
to me. Jan, any ideas?
