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SubjectRe: [PATCH v2] nvme: fix multipath crash when ANA desactivated
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On 7/5/2019 5:05 PM, Marta Rybczynska wrote:
> Fix a crash with multipath activated. It happends when ANA log
> page is larger than MDTS and because of that ANA is disabled.
> The driver then tries to access unallocated buffer when connecting
> to a nvme target. The signature is as follows:
>
> [ 300.433586] nvme nvme0: ANA log page size (8208) larger than MDTS (8192).
> [ 300.435387] nvme nvme0: disabling ANA support.
> [ 300.437835] nvme nvme0: creating 4 I/O queues.
> [ 300.459132] nvme nvme0: new ctrl: NQN "nqn.0.0.0", addr 10.91.0.1:8009
> [ 300.464609] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
> [ 300.466342] #PF error: [normal kernel read fault]
> [ 300.467385] PGD 0 P4D 0
> [ 300.467987] Oops: 0000 [#1] SMP PTI
> [ 300.468787] CPU: 3 PID: 50 Comm: kworker/u8:1 Not tainted 5.0.20kalray+ #4
> [ 300.470264] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
> [ 300.471532] Workqueue: nvme-wq nvme_scan_work [nvme_core]
> [ 300.472724] RIP: 0010:nvme_parse_ana_log+0x21/0x140 [nvme_core]
> [ 300.474038] Code: 45 01 d2 d8 48 98 c3 66 90 0f 1f 44 00 00 41 57 41 56 41 55 41 54 55 53 48 89 fb 48 83 ec 08 48 8b af 20 0a 00 00 48 89 34 24 <66> 83 7d 08 00 0f 84 c6 00 00 00 44 8b 7d 14 49 89 d5 8b 55 10 48
> [ 300.477374] RSP: 0018:ffffa50e80fd7cb8 EFLAGS: 00010296
> [ 300.478334] RAX: 0000000000000001 RBX: ffff9130f1872258 RCX: 0000000000000000
> [ 300.479784] RDX: ffffffffc06c4c30 RSI: ffff9130edad4280 RDI: ffff9130f1872258
> [ 300.481488] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000044
> [ 300.483203] R10: 0000000000000220 R11: 0000000000000040 R12: ffff9130f18722c0
> [ 300.484928] R13: ffff9130f18722d0 R14: ffff9130edad4280 R15: ffff9130f18722c0
> [ 300.486626] FS: 0000000000000000(0000) GS:ffff9130f7b80000(0000) knlGS:0000000000000000
> [ 300.488538] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 300.489907] CR2: 0000000000000008 CR3: 00000002365e6000 CR4: 00000000000006e0
> [ 300.491612] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 300.493303] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 300.494991] Call Trace:
> [ 300.495645] nvme_mpath_add_disk+0x5c/0xb0 [nvme_core]
> [ 300.496880] nvme_validate_ns+0x2ef/0x550 [nvme_core]
> [ 300.498105] ? nvme_identify_ctrl.isra.45+0x6a/0xb0 [nvme_core]
> [ 300.499539] nvme_scan_work+0x2b4/0x370 [nvme_core]
> [ 300.500717] ? __switch_to_asm+0x35/0x70
> [ 300.501663] process_one_work+0x171/0x380
> [ 300.502340] worker_thread+0x49/0x3f0
> [ 300.503079] kthread+0xf8/0x130
> [ 300.503795] ? max_active_store+0x80/0x80
> [ 300.504690] ? kthread_bind+0x10/0x10
> [ 300.505502] ret_from_fork+0x35/0x40
> [ 300.506280] Modules linked in: nvme_tcp nvme_rdma rdma_cm iw_cm ib_cm ib_core nvme_fabrics nvme_core xt_physdev ip6table_raw ip6table_mangle ip6table_filter ip6_tables xt_comment iptable_nat nf_nat_ipv4 nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xt_CHECKSUM iptable_mangle iptable_filter veth ebtable_filter ebtable_nat ebtables iptable_raw vxlan ip6_udp_tunnel udp_tunnel sunrpc joydev pcspkr virtio_balloon br_netfilter bridge stp llc ip_tables xfs libcrc32c ata_generic pata_acpi virtio_net virtio_console net_failover virtio_blk failover ata_piix serio_raw libata virtio_pci virtio_ring virtio
> [ 300.514984] CR2: 0000000000000008
> [ 300.515569] ---[ end trace faa2eefad7e7f218 ]---
> [ 300.516354] RIP: 0010:nvme_parse_ana_log+0x21/0x140 [nvme_core]
> [ 300.517330] Code: 45 01 d2 d8 48 98 c3 66 90 0f 1f 44 00 00 41 57 41 56 41 55 41 54 55 53 48 89 fb 48 83 ec 08 48 8b af 20 0a 00 00 48 89 34 24 <66> 83 7d 08 00 0f 84 c6 00 00 00 44 8b 7d 14 49 89 d5 8b 55 10 48
> [ 300.520353] RSP: 0018:ffffa50e80fd7cb8 EFLAGS: 00010296
> [ 300.521229] RAX: 0000000000000001 RBX: ffff9130f1872258 RCX: 0000000000000000
> [ 300.522399] RDX: ffffffffc06c4c30 RSI: ffff9130edad4280 RDI: ffff9130f1872258
> [ 300.523560] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000044
> [ 300.524734] R10: 0000000000000220 R11: 0000000000000040 R12: ffff9130f18722c0
> [ 300.525915] R13: ffff9130f18722d0 R14: ffff9130edad4280 R15: ffff9130f18722c0
> [ 300.527084] FS: 0000000000000000(0000) GS:ffff9130f7b80000(0000) knlGS:0000000000000000
> [ 300.528396] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 300.529440] CR2: 0000000000000008 CR3: 00000002365e6000 CR4: 00000000000006e0
> [ 300.530739] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 300.531989] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 300.533264] Kernel panic - not syncing: Fatal exception
> [ 300.534338] Kernel Offset: 0x17c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
> [ 300.536227] ---[ end Kernel panic - not syncing: Fatal exception ]---
>
> Signed-off-by: Marta Rybczynska <marta.rybczynska@kalray.eu>
> Tested-by: Jean-Baptiste Riaux <jbriaux@kalray.eu>
> ---
> drivers/nvme/host/multipath.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 499acf0..5ba982b 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -14,7 +14,8 @@
>
> inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl)
> {
> - return multipath && ctrl->subsys && (ctrl->subsys->cmic & (1 << 3));
> + return multipath && ctrl->ana_log_buf && ctrl->subsys &&
> + (ctrl->subsys->cmic & (1 << 3));
> }
>
> /*
> @@ -614,7 +615,10 @@ int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
> {
> int error;
>
> - if (!nvme_ctrl_use_ana(ctrl))
> + /* check if multipath is enabled and we have the capability */
> + if (!multipath)
> + return 0;
> + if (!ctrl->subsys || ((ctrl->subsys->cmic & (1 << 3)) != 0))

shouldn't it be:

if (!ctrl->subsys || ((ctrl->subsys->cmic & (1 << 3)) == 0))

or

if (!ctrl->subsys || !(ctrl->subsys->cmic & (1 << 3)))


Otherwise, you don't really do any initialization and return 0 in case you have the capability, right ?

> return 0;
>
> ctrl->anacap = id->anacap;

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