[PATCH v4] NFSv4: fix possible NULL-pointer dereference in nfs42_complete_copies()
From: zhangyanjun
Date: Tue Oct 01 2024 - 03:28:03 EST
From: Yanjun Zhang <zhangyanjun@xxxxxxxx>
On the node of an NFS client, some files saved in the mountpoint of the
NFS server were coping data within the same server. Accidentally, the
nfs42_complete_copies() got a NULL-pointer dereference crash with the
following syslog:
[232064.838881] NFSv4: state recovery failed for open file nfs/pvc-12b5200d-cd0f-46a3-b9f0-af8f4fe0ef64.qcow2, error = -116
[232064.839360] NFSv4: state recovery failed for open file nfs/pvc-12b5200d-cd0f-46a3-b9f0-af8f4fe0ef64.qcow2, error = -116
[232066.588183] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000058
[232066.588586] Mem abort info:
[232066.588701] ESR = 0x0000000096000007
[232066.588862] EC = 0x25: DABT (current EL), IL = 32 bits
[232066.589084] SET = 0, FnV = 0
[232066.589216] EA = 0, S1PTW = 0
[232066.589340] FSC = 0x07: level 3 translation fault
[232066.589559] Data abort info:
[232066.589683] ISV = 0, ISS = 0x00000007
[232066.589842] CM = 0, WnR = 0
[232066.589967] user pgtable: 64k pages, 48-bit VAs, pgdp=00002000956ff400
[232066.590231] [0000000000000058] pgd=08001100ae100003, p4d=08001100ae100003, pud=08001100ae100003, pmd=08001100b3c00003, pte=0000000000000000
[232066.590757] Internal error: Oops: 96000007 [#1] SMP
[232066.590958] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm vhost_net vhost vhost_iotlb tap tun ipt_rpfilter xt_multiport ip_set_hash_ip ip_set_hash_net xfrm_interface xfrm6_tunnel tunnel4 tunnel6 esp4 ah4 wireguard libcurve25519_generic veth xt_addrtype xt_set nf_conntrack_netlink ip_set_hash_ipportnet ip_set_hash_ipportip ip_set_bitmap_port ip_set_hash_ipport dummy ip_set ip_vs_sh ip_vs_wrr ip_vs_rr ip_vs iptable_filter sch_ingress nfnetlink_cttimeout vport_gre ip_gre ip_tunnel gre vport_geneve geneve vport_vxlan vxlan ip6_udp_tunnel udp_tunnel openvswitch nf_conncount dm_round_robin dm_service_time dm_multipath xt_nat xt_MASQUERADE nft_chain_nat nf_nat xt_mark xt_conntrack xt_comment nft_compat nft_counter nf_tables nfnetlink ocfs2 ocfs2_nodemanager ocfs2_stackglue iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ipmi_ssif nbd overlay 8021q garp mrp bonding tls rfkill sunrpc ext4 mbcache jbd2
[232066.591052] vfat fat cas_cache cas_disk ses enclosure scsi_transport_sas sg acpi_ipmi ipmi_si ipmi_devintf ipmi_msghandler ip_tables vfio_pci vfio_pci_core vfio_virqfd vfio_iommu_type1 vfio dm_mirror dm_region_hash dm_log dm_mod nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter bridge stp llc fuse xfs libcrc32c ast drm_vram_helper qla2xxx drm_kms_helper syscopyarea crct10dif_ce sysfillrect ghash_ce sysimgblt sha2_ce fb_sys_fops cec sha256_arm64 sha1_ce drm_ttm_helper ttm nvme_fc igb sbsa_gwdt nvme_fabrics drm nvme_core i2c_algo_bit i40e scsi_transport_fc megaraid_sas aes_neon_bs
[232066.596953] CPU: 6 PID: 4124696 Comm: 10.253.166.125- Kdump: loaded Not tainted 5.15.131-9.cl9_ocfs2.aarch64 #1
[232066.597356] Hardware name: Great Wall .\x93\x8e...RF6260 V5/GWMSSE2GL1T, BIOS T656FBE_V3.0.18 2024-01-06
[232066.597721] pstate: 20400009 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[232066.598034] pc : nfs4_reclaim_open_state+0x220/0x800 [nfsv4]
[232066.598327] lr : nfs4_reclaim_open_state+0x12c/0x800 [nfsv4]
[232066.598595] sp : ffff8000f568fc70
[232066.598731] x29: ffff8000f568fc70 x28: 0000000000001000 x27: ffff21003db33000
[232066.599030] x26: ffff800005521ae0 x25: ffff0100f98fa3f0 x24: 0000000000000001
[232066.599319] x23: ffff800009920008 x22: ffff21003db33040 x21: ffff21003db33050
[232066.599628] x20: ffff410172fe9e40 x19: ffff410172fe9e00 x18: 0000000000000000
[232066.599914] x17: 0000000000000000 x16: 0000000000000004 x15: 0000000000000000
[232066.600195] x14: 0000000000000000 x13: ffff800008e685a8 x12: 00000000eac0c6e6
[232066.600498] x11: 0000000000000000 x10: 0000000000000008 x9 : ffff8000054e5828
[232066.600784] x8 : 00000000ffffffbf x7 : 0000000000000001 x6 : 000000000a9eb14a
[232066.601062] x5 : 0000000000000000 x4 : ffff70ff8a14a800 x3 : 0000000000000058
[232066.601348] x2 : 0000000000000001 x1 : 54dce46366daa6c6 x0 : 0000000000000000
[232066.601636] Call trace:
[232066.601749] nfs4_reclaim_open_state+0x220/0x800 [nfsv4]
[232066.601998] nfs4_do_reclaim+0x1b8/0x28c [nfsv4]
[232066.602218] nfs4_state_manager+0x928/0x10f0 [nfsv4]
[232066.602455] nfs4_run_state_manager+0x78/0x1b0 [nfsv4]
[232066.602690] kthread+0x110/0x114
[232066.602830] ret_from_fork+0x10/0x20
[232066.602985] Code: 1400000d f9403f20 f9402e61 91016003 (f9402c00)
[232066.603284] SMP: stopping secondary CPUs
[232066.606936] Starting crashdump kernel...
[232066.607146] Bye!
Analysing the vmcore, we know that nfs4_copy_state listed by destination
nfs_server->ss_copies was added by the field copies in handle_async_copy(),
and we found a waiting copy process with the stack as:
PID: 3511963 TASK: ffff710028b47e00 CPU: 0 COMMAND: "cp"
#0 [ffff8001116ef740] __switch_to at ffff8000081b92f4
#1 [ffff8001116ef760] __schedule at ffff800008dd0650
#2 [ffff8001116ef7c0] schedule at ffff800008dd0a00
#3 [ffff8001116ef7e0] schedule_timeout at ffff800008dd6aa0
#4 [ffff8001116ef860] __wait_for_common at ffff800008dd166c
#5 [ffff8001116ef8e0] wait_for_completion_interruptible at ffff800008dd1898
#6 [ffff8001116ef8f0] handle_async_copy at ffff8000055142f4 [nfsv4]
#7 [ffff8001116ef970] _nfs42_proc_copy at ffff8000055147c8 [nfsv4]
#8 [ffff8001116efa80] nfs42_proc_copy at ffff800005514cf0 [nfsv4]
#9 [ffff8001116efc50] __nfs4_copy_file_range.constprop.0 at ffff8000054ed694 [nfsv4]
The NULL-pointer dereference was due to nfs42_complete_copies() listed
the nfs_server->ss_copies by the field ss_copies of nfs4_copy_state.
So the nfs4_copy_state address ffff0100f98fa3f0 was offset by 0x10 and
the data accessed through this pointer was also incorrect. Generally,
the ordered list nfs4_state_owner->so_states indicate open(O_RDWR) or
open(O_WRITE) states are reclaimed firstly by nfs4_reclaim_open_state().
When destination state reclaim is failed with NFS_STATE_RECOVERY_FAILED
and copies are not deleted in nfs_server->ss_copies, the source state
may be passed to the nfs42_complete_copies() process earlier, resulting
in this crash scene finally. To solve this issue, we add a list_head
nfs_server->ss_src_copies for a server-to-server copy specially.
Fixes: 0e65a32c8a56 ("NFS: handle source server reboot")
Signed-off-by: Yanjun Zhang <zhangyanjun@xxxxxxxx>
Reviewed-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
v2:
- add an initialiser for the new list in nfs_alloc_server().
- change the new list name from ds_copies to ss_src_copies.
v3:
- correct the commit ID of Fixes tags.
- append parentheses to any function names.
- modify the title and text to get smaller line lengths.
v4:
- add Reviewed-by tags and patch changelogs.
- adjust the patch description more accurately.
fs/nfs/client.c | 1 +
fs/nfs/nfs42proc.c | 2 +-
fs/nfs/nfs4state.c | 2 +-
include/linux/nfs_fs_sb.h | 1 +
4 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 8286edd60..c49d5cce5 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -983,6 +983,7 @@ struct nfs_server *nfs_alloc_server(void)
INIT_LIST_HEAD(&server->layouts);
INIT_LIST_HEAD(&server->state_owners_lru);
INIT_LIST_HEAD(&server->ss_copies);
+ INIT_LIST_HEAD(&server->ss_src_copies);
atomic_set(&server->active, 0);
diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
index 28704f924..531c9c20e 100644
--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -218,7 +218,7 @@ static int handle_async_copy(struct nfs42_copy_res *res,
if (dst_server != src_server) {
spin_lock(&src_server->nfs_client->cl_lock);
- list_add_tail(©->src_copies, &src_server->ss_copies);
+ list_add_tail(©->src_copies, &src_server->ss_src_copies);
spin_unlock(&src_server->nfs_client->cl_lock);
}
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 877f682b4..00516982b 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1596,7 +1596,7 @@ static void nfs42_complete_copies(struct nfs4_state_owner *sp, struct nfs4_state
complete(©->completion);
}
}
- list_for_each_entry(copy, &sp->so_server->ss_copies, src_copies) {
+ list_for_each_entry(copy, &sp->so_server->ss_src_copies, src_copies) {
if ((test_bit(NFS_CLNT_SRC_SSC_COPY_STATE, &state->flags) &&
!nfs4_stateid_match_other(&state->stateid,
©->parent_src_state->stateid)))
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 1df86ab98..793a4a610 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -240,6 +240,7 @@ struct nfs_server {
struct list_head layouts;
struct list_head delegations;
struct list_head ss_copies;
+ struct list_head ss_src_copies;
unsigned long delegation_gen;
unsigned long mig_gen;
--
2.31.1