On Mon, Jan 20, 2025 at 6:09 PM Ignat Korchagin <ignat@xxxxxxxxxxxxxx> wrote:
>
>
>
> > On 15 Jan 2025, at 10:36, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> > 6.6-stable review patch. If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: Amir Goldstein <amir73il@xxxxxxxxx>
> >
> > [ Upstream commit 5b02bfc1e7e3811c5bf7f0fa626a0694d0dbbd77 ]
> >
> > When lower fs is a nested overlayfs, calling encode_fh() on a lower
> > directory dentry may trigger copy up and take sb_writers on the upper fs
> > of the lower nested overlayfs.
> >
> > The lower nested overlayfs may have the same upper fs as this overlayfs,
> > so nested sb_writers lock is illegal.
> >
> > Move all the callers that encode lower fh to before ovl_want_write().
> >
> > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> > Stable-dep-of: c45beebfde34 ("ovl: support encoding fid from inode with no alias")
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> > ---
>
> Hi,
>
> This patch seems to trigger the following warning on 6.6.72, when running simple “$ docker run --rm -it debian” (creating a container):
>
> ------------[ cut here ]------------
> WARNING: CPU: 12 PID: 668 at fs/namespace.c:1245 cleanup_mnt+0x130/0x150
> Modules linked in: xt_conntrack(E) nft_chain_nat(E) xt_MASQUERADE(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E) bridge(E) stp(E) llc(E) xfrm_user(E) xfrm_algo(E) xt_addrtype(E) nft_compat(E) nf_tables(E) overlay(E) kvm_amd(E) ccp(E) kvm(E) irqbypass(E) crc32_pclmul(E) sha512_ssse3(E) sha256_ssse3(E) sha1_ssse3(E) aesni_intel(E) crypto_simd(E) cryptd(E) iTCO_wdt(E) virtio_console(E) virtio_balloon(E) iTCO_vendor_support(E) tiny_power_button(E) button(E) sch_fq_codel(E) fuse(E) nfnetlink(E) vsock_loopback(E) vmw_vsock_virtio_transport_common(E) vsock(E) efivarfs(E) ip_tables(E) x_tables(E) virtio_net(E) net_failover(E) virtio_blk(E) virtio_scsi(E) failover(E) crc32c_intel(E) i2c_i801(E) virtio_pci(E) virtio_pci_legacy_dev(E) i2c_smbus(E) lpc_ich(E) virtio_pci_modern_dev(E) mfd_core(E) virtio(E) virtio_ring(E)
> CPU: 12 PID: 668 Comm: dockerd Tainted: G E 6.6.71+ #18
> Hardware name: KubeVirt None/RHEL, BIOS edk2-20230524-3.el9 05/24/2023
> RIP: 0010:cleanup_mnt+0x130/0x150
> Code: 2c 01 00 00 85 c0 75 16 e8 6d fb ff ff eb 8a c7 87 2c 01 00 00 00 00 00 00 e9 6a ff ff ff c7 87 2c 01 00 00 00 00 00 00 eb de <0f> 0b 48 83 bd 30 01 00 00 00 0f 84 e9 fe ff ff 48 89 ef e8 18 e7
> RSP: 0018:ffffc9000095fec8 EFLAGS: 00010282
> RAX: 00000000fffffffe RBX: 0000000000000000 RCX: 0000000000000010
> RDX: 0000000000000010 RSI: 0000000000000010 RDI: 0000000000000010
> RBP: ffff888109ea57c0 R08: ffffffffbc27ab60 R09: 0000000000000000
> R10: 0000000000037420 R11: 0000000000000000 R12: ffff88810acba9bc
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> FS: 00007f1041ffb6c0(0000) GS:ffff88903fc00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000c000b7f02f CR3: 00000001034ca002 CR4: 0000000000770ee0
> PKRU: 55555554
> Call Trace:
> <TASK>
> ? cleanup_mnt+0x130/0x150
> ? __warn+0x81/0x130
> ? cleanup_mnt+0x130/0x150
> ? report_bug+0x16f/0x1a0
> ? handle_bug+0x53/0x90
> ? exc_invalid_op+0x17/0x70
> ? asm_exc_invalid_op+0x1a/0x20
> ? cleanup_mnt+0x130/0x150
> ? cleanup_mnt+0x13/0x150
> task_work_run+0x5d/0x90
> exit_to_user_mode_prepare+0xf8/0x100
> syscall_exit_to_user_mode+0x21/0x40
> ? srso_alias_return_thunk+0x5/0xfbef5
> do_syscall_64+0x45/0x90
> entry_SYSCALL_64_after_hwframe+0x60/0xca
> RIP: 0033:0x55d0e0726dee
> Code: 48 83 ec 38 e8 13 00 00 00 48 83 c4 38 5d c3 cc cc cc cc cc cc cc cc cc cc cc cc cc 49 89 f2 48 89 fa 48 89 ce 48 89 df 0f 05 <48> 3d 01 f0 ff ff 76 15 48 f7 d8 48 89 c1 48 c7 c0 ff ff ff ff 48
> RSP: 002b:000000c000145a10 EFLAGS: 00000216 ORIG_RAX: 00000000000000a6
> RAX: 0000000000000000 RBX: 000000c000b7fce0 RCX: 000055d0e0726dee
> RDX: 0000000000000000 RSI: 0000000000000002 RDI: 000000c000b7fce0
> RBP: 000000c000145a50 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000216 R12: 000000c000b7fce0
> R13: 0000000000000000 R14: 000000c000b06e00 R15: 1fffffffffffffff
> </TASK>
> ---[ end trace 0000000000000000 ]—
>
> This commit was pointed by my bisecting 6.6.71..6.6.72, but to double-check it I had to revert the following commits to make 6.6.72 compile and not exhibit the issue:
Can you say what the compile error was?
Maybe it is easy to fix without reverting the entire bunch.
Just by looking, it is hard for me to guess what caused the scripts to
pull in this dependency patch.
>
> * a3f8a2b13a277d942c810d2ccc654d5bc824a430 (“ovl: pass realinode to ovl_encode_real_fh() instead of realdentry
> ”) [ Upstream commit 07aeefae7ff44d80524375253980b1bdee2396b0 ]
> * 26423e18cd6f709ca4fe7194c29c11658cd0cdd0 (“ovl: do not encode lower fh with upper sb_writers held”) [ Upstream commit 5b02bfc1e7e3811c5bf7f0fa626a0694d0dbbd77 ]
> * a1a541fbfa7e97c1100144db34b57553d7164ce5 ("ovl: support encoding fid from inode with no alias”) [ Upstream commit c45beebfde34aa71afbc48b2c54cdda623515037 ]
>
> I can also confirm we don’t see this warning on the latest 6.12.10 release, so perhaps we have missed some dependencies in 6.6?
>
Nah. pulling in the dependency patch was wrong.
This patch was not supposed to be applied detached from the entire series
https://lore.kernel.org/linux-unionfs/20230816152334.924960-1-amir73il@xxxxxxxxx/
and I think this is a risky series to backport.
Thanks,
Amir.
