kernel/fs/nfsd, branch linux-rolling-lts

nfsd: Fix cred ref leak in nfsd_nl_listener_set_doit().

2026-03-19T15:08:34Z

commit 92978c83bb4eef55d02a6c990c01c423131eefa7 upstream. nfsd_nl_listener_set_doit() uses get_current_cred() without put_cred(). As we can see from other callers, svc_xprt_create_from_sa() does not require the extra refcount. nfsd_nl_listener_set_doit() is always in the process context, sendmsg(), and current->cred does not go away. Let's use current_cred() in nfsd_nl_listener_set_doit(). Fixes: 16a471177496 ("NFSD: add listener-{set,get} netlink command") Cc: stable@vger.kernel.org Signed-off-by: Kuniyuki Iwashima Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: Fix cred ref leak in nfsd_nl_threads_set_doit().

2026-03-12T11:09:41Z

commit 1cb968a2013ffa8112d52ebe605009ea1c6a582c upstream. syzbot reported memory leak of struct cred. [0] nfsd_nl_threads_set_doit() passes get_current_cred() to nfsd_svc(), but put_cred() is not called after that. The cred is finally passed down to _svc_xprt_create(), which calls get_cred() with the cred for struct svc_xprt. The ownership of the refcount by get_current_cred() is not transferred to anywhere and is just leaked. nfsd_svc() is also called from write_threads(), but it does not bump file->f_cred there. nfsd_nl_threads_set_doit() is called from sendmsg() and current->cred does not go away. Let's use current_cred() in nfsd_nl_threads_set_doit(). [0]: BUG: memory leak unreferenced object 0xffff888108b89480 (size 184): comm "syz-executor", pid 5994, jiffies 4294943386 hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 369454a7): kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline] slab_post_alloc_hook mm/slub.c:4958 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x412/0x580 mm/slub.c:5270 prepare_creds+0x22/0x600 kernel/cred.c:185 copy_creds+0x44/0x290 kernel/cred.c:286 copy_process+0x7a7/0x2870 kernel/fork.c:2086 kernel_clone+0xac/0x6e0 kernel/fork.c:2651 __do_sys_clone+0x7f/0xb0 kernel/fork.c:2792 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 924f4fb003ba ("NFSD: convert write_threads to netlink command") Cc: stable@vger.kernel.org Reported-by: syzbot+dd3b43aa0204089217ee@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69744674.a00a0220.33ccc7.0000.GAE@google.com/ Tested-by: syzbot+dd3b43aa0204089217ee@syzkaller.appspotmail.com Signed-off-by: Kuniyuki Iwashima Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: fix return error code for nfsd_map_name_to_[ug]id

2026-03-04T12:21:17Z

[ Upstream commit 404d779466646bf1461f2090ff137e99acaecf42 ] idmap lookups can time out while the cache is waiting for a userspace upcall reply. In that case cache_check() returns -ETIMEDOUT to callers. The nfsd_map_name_to_[ug]id functions currently proceed with attempting to map the id to a kuid despite a potentially temporary failure to perform the idmap lookup. This results in the code returning the error NFSERR_BADOWNER which can cause client operations to return to userspace with failure. Fix this by returning the failure status before attempting kuid mapping. This will return NFSERR_JUKEBOX on idmap lookup timeout so that clients can retry the operation instead of aborting it. Fixes: 65e10f6d0ab0 ("nfsd: Convert idmap to use kuids and kgids") Cc: stable@vger.kernel.org Signed-off-by: Anthony Iliopoulos Reviewed-by: NeilBrown Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

NFSD: fix setting FMODE_NOCMTIME in nfs4_open_delegation

2026-03-04T12:21:17Z

[ Upstream commit 41b0a87bc60d5ccfa8575481ddb4d4d8758507fa ] fstests generic/215 and generic/407 were failing because the server wasn't updating mtime properly. When deleg attribute support is not compiled in and thus no attribute delegation was given, the server was skipping updating mtime and ctime because FMODE_NOCMTIME was uncoditionally set for the write delegation. Fixes: e5e9b24ab8fa ("nfsd: freeze c/mtime updates with outstanding WRITE_ATTRS delegation") Cc: stable@vger.kernel.org Signed-off-by: Olga Kornievskaia Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

nfsd: never defer requests during idmap lookup

2026-02-26T22:59:18Z

[ Upstream commit f9c206cdc4266caad6a9a7f46341420a10f03ccb ] During v4 request compound arg decoding, some ops (e.g. SETATTR) can trigger idmap lookup upcalls. When those upcall responses get delayed beyond the allowed time limit, cache_check() will mark the request for deferral and cause it to be dropped. This prevents nfs4svc_encode_compoundres from being executed, and thus the session slot flag NFSD4_SLOT_INUSE never gets cleared. Subsequent client requests will fail with NFSERR_JUKEBOX, given that the slot will be marked as in-use, making the SEQUENCE op fail. Fix this by making sure that the RQ_USEDEFERRAL flag is always clear during nfs4svc_decode_compoundargs(), since no v4 request should ever be deferred. Fixes: 2f425878b6a7 ("nfsd: don't use the deferral service, return NFS4ERR_DELAY") Signed-off-by: Anthony Iliopoulos Reviewed-by: NeilBrown Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

NFS: NFSERR_INVAL is not defined by NFSv2

2026-02-26T22:59:18Z

[ Upstream commit 0ac903d1bfdce8ff40657c2b7d996947b72b6645 ] A documenting comment in include/uapi/linux/nfs.h claims incorrectly that NFSv2 defines NFSERR_INVAL. There is no such definition in either RFC 1094 or https://pubs.opengroup.org/onlinepubs/9629799/chap7.htm NFS3ERR_INVAL is introduced in RFC 1813. NFSD returns NFSERR_INVAL for PROC_GETACL, which has no specification (yet). However, nfsd_map_status() maps nfserr_symlink and nfserr_wrong_type to nfserr_inval, which does not align with RFC 1094. This logic was introduced only recently by commit 438f81e0e92a ("nfsd: move error choice for incorrect object types to version-specific code."). Given that we have no INVAL or SERVERFAULT status in NFSv2, probably the only choice is NFSERR_IO. Fixes: 438f81e0e92a ("nfsd: move error choice for incorrect object types to version-specific code.") Reviewed-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

NFSD: Remove NFSERR_EAGAIN

2026-01-17T15:35:10Z

commit c6c209ceb87f64a6ceebe61761951dcbbf4a0baa upstream. I haven't found an NFSERR_EAGAIN in RFCs 1094, 1813, 7530, or 8881. None of these RFCs have an NFS status code that match the numeric value "11". Based on the meaning of the EAGAIN errno, I presume the use of this status in NFSD means NFS4ERR_DELAY. So replace the one usage of nfserr_eagain, and remove it from NFSD's NFS status conversion tables. As far as I can tell, NFSERR_EAGAIN has existed since the pre-git era, but was not actually used by any code until commit f4e44b393389 ("NFSD: delay unmount source's export after inter-server copy completed."), at which time it become possible for NFSD to return a status code of 11 (which is not valid NFS protocol). Fixes: f4e44b393389 ("NFSD: delay unmount source's export after inter-server copy completed.") Cc: stable@vger.kernel.org Reviewed-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

NFSD: net ref data still needs to be freed even if net hasn't startup

2026-01-17T15:35:10Z

commit 0b88bfa42e5468baff71909c2f324a495318532b upstream. When the NFSD instance doesn't to startup, the net ref data memory is not properly reclaimed, which triggers the memory leak issue reported by syzbot [1]. To avoid the problem reported in [1], the net ref data memory reclamation action is moved outside of nfsd_net_up when the net is shutdown. [1] unreferenced object 0xffff88812a39dfc0 (size 64): backtrace (crc a2262fc6): percpu_ref_init+0x94/0x1e0 lib/percpu-refcount.c:76 nfsd_create_serv+0xbe/0x260 fs/nfsd/nfssvc.c:605 nfsd_nl_listener_set_doit+0x62/0xb00 fs/nfsd/nfsctl.c:1882 genl_family_rcv_msg_doit+0x11e/0x190 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x2fd/0x440 net/netlink/genetlink.c:1210 BUG: memory leak Reported-by: syzbot+6ee3b889bdeada0a6226@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=6ee3b889bdeada0a6226 Fixes: 39972494e318 ("nfsd: update percpu_ref to manage references on nfsd_net") Cc: stable@vger.kernel.org Signed-off-by: Edward Adam Davis Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: check that server is running in unlock_filesystem

2026-01-17T15:35:10Z

commit d0424066fcd294977f310964bed6f2a487fa4515 upstream. If we are trying to unlock the filesystem via an administrative interface and nfsd isn't running, it crashes the server. This happens currently because nfsd4_revoke_states() access state structures (eg., conf_id_hashtbl) that has been freed as a part of the server shutdown. [ 59.465072] Call trace: [ 59.465308] nfsd4_revoke_states+0x1b4/0x898 [nfsd] (P) [ 59.465830] write_unlock_fs+0x258/0x440 [nfsd] [ 59.466278] nfsctl_transaction_write+0xb0/0x120 [nfsd] [ 59.466780] vfs_write+0x1f0/0x938 [ 59.467088] ksys_write+0xfc/0x1f8 [ 59.467395] __arm64_sys_write+0x74/0xb8 [ 59.467746] invoke_syscall.constprop.0+0xdc/0x1e8 [ 59.468177] do_el0_svc+0x154/0x1d8 [ 59.468489] el0_svc+0x40/0xe0 [ 59.468767] el0t_64_sync_handler+0xa0/0xe8 [ 59.469138] el0t_64_sync+0x1ac/0x1b0 Ensure this can't happen by taking the nfsd_mutex and checking that the server is still up, and then holding the mutex across the call to nfsd4_revoke_states(). Reviewed-by: NeilBrown Reviewed-by: Jeff Layton Fixes: 1ac3629bf0125 ("nfsd: prepare for supporting admin-revocation of state") Cc: stable@vger.kernel.org Signed-off-by: Olga Kornievskaia Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: use correct loop termination in nfsd4_revoke_states()

2026-01-17T15:35:10Z

commit fb321998de7639f1954430674475e469fb529d9c upstream. The loop in nfsd4_revoke_states() stops one too early because the end value given is CLIENT_HASH_MASK where it should be CLIENT_HASH_SIZE. This means that an admin request to drop all locks for a filesystem will miss locks held by clients which hash to the maximum possible hash value. Fixes: 1ac3629bf012 ("nfsd: prepare for supporting admin-revocation of state") Cc: stable@vger.kernel.org Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman