kernel/linux.git/fs/nfs/write.c, branch v6.6.131

NFS: Fix a deadlock involving nfs_release_folio()

2026-03-25T10:05:59+00:00

[ Upstream commit cce0be6eb4971456b703aaeafd571650d314bcca ] Wang Zhaolong reports a deadlock involving NFSv4.1 state recovery waiting on kthreadd, which is attempting to reclaim memory by calling nfs_release_folio(). The latter cannot make progress due to state recovery being needed. It seems that the only safe thing to do here is to kick off a writeback of the folio, without waiting for completion, or else kicking off an asynchronous commit. Reported-by: Wang Zhaolong Fixes: 96780ca55e3c ("NFS: fix up nfs_release_folio() to try to release the page") Signed-off-by: Trond Myklebust [ Minor conflict resolved. ] Signed-off-by: Li hongliang <1468888505@139.com> Signed-off-by: Greg Kroah-Hartman

nfs: pass explicit offset/count to trace events

2026-03-25T10:05:59+00:00

[ Upstream commit fada32ed6dbc748f447c8d050a961b75d946055a ] nfs_folio_length is unsafe to use without having the folio locked and a check for a NULL ->f_mapping that protects against truncations and can lead to kernel crashes. E.g. when running xfstests generic/065 with all nfs trace points enabled. Follow the model of the XFS trace points and pass in an explіcit offset and length. This has the additional benefit that these values can be more accurate as some of the users touch partial folio ranges. Fixes: eb5654b3b89d ("NFS: Enable tracing of nfs_invalidate_folio() and nfs_launder_folio()") Reported-by: Chuck Lever Signed-off-by: Christoph Hellwig Signed-off-by: Anna Schumaker [ Minor conflict resolved. ] Signed-off-by: Li hongliang <1468888505@139.com> Signed-off-by: Greg Kroah-Hartman

NFS: check if suid/sgid was cleared after a write as needed

2025-11-24T09:29:57+00:00

[ Upstream commit 9ff022f3820a31507cb93be6661bf5f3ca0609a4 ] I noticed xfstests generic/193 and generic/355 started failing against knfsd after commit e7a8ebc305f2 ("NFSD: Offer write delegation for OPEN with OPEN4_SHARE_ACCESS_WRITE"). I ran those same tests against ONTAP (which has had write delegation support for a lot longer than knfsd) and they fail there too... so while it's a new failure against knfsd, it isn't an entirely new failure. Add the NFS_INO_REVAL_FORCED flag so that the presence of a delegation doesn't keep the inode from being revalidated to fetch the updated mode. Signed-off-by: Scott Mayhew Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin

NFS: Fix a race when updating an existing write

2025-09-04T13:30:20+00:00

commit 76d2e3890fb169168c73f2e4f8375c7cc24a765e upstream. After nfs_lock_and_join_requests() tests for whether the request is still attached to the mapping, nothing prevents a call to nfs_inode_remove_request() from succeeding until we actually lock the page group. The reason is that whoever called nfs_inode_remove_request() doesn't necessarily have a lock on the page group head. So in order to avoid races, let's take the page group lock earlier in nfs_lock_and_join_requests(), and hold it across the removal of the request in nfs_inode_remove_request(). Reported-by: Jeff Layton Tested-by: Joe Quanaim Tested-by: Andrew Steffen Reviewed-by: Jeff Layton Fixes: bd37d6fce184 ("NFSv4: Convert nfs_lock_and_join_requests() to use nfs_page_find_head_request()") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman

nfs: fold nfs_page_group_lock_subrequests into nfs_lock_and_join_requests

2025-09-04T13:30:20+00:00

commit 25edbcac6e32eab345e470d56ca9974a577b878b upstream. Fold nfs_page_group_lock_subrequests into nfs_lock_and_join_requests to prepare for future changes to this code, and move the helpers to write.c as well. Signed-off-by: Christoph Hellwig Reviewed-by: Sagi Grimberg Signed-off-by: Anna Schumaker Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman

nfs: fix UAF in direct writes

2024-04-03T13:28:29+00:00

[ Upstream commit 17f46b803d4f23c66cacce81db35fef3adb8f2af ] In production we have been hitting the following warning consistently ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 17 PID: 1800359 at lib/refcount.c:28 refcount_warn_saturate+0x9c/0xe0 Workqueue: nfsiod nfs_direct_write_schedule_work [nfs] RIP: 0010:refcount_warn_saturate+0x9c/0xe0 PKRU: 55555554 Call Trace: ? __warn+0x9f/0x130 ? refcount_warn_saturate+0x9c/0xe0 ? report_bug+0xcc/0x150 ? handle_bug+0x3d/0x70 ? exc_invalid_op+0x16/0x40 ? asm_exc_invalid_op+0x16/0x20 ? refcount_warn_saturate+0x9c/0xe0 nfs_direct_write_schedule_work+0x237/0x250 [nfs] process_one_work+0x12f/0x4a0 worker_thread+0x14e/0x3b0 ? ZSTD_getCParams_internal+0x220/0x220 kthread+0xdc/0x120 ? __btf_name_valid+0xa0/0xa0 ret_from_fork+0x1f/0x30 This is because we're completing the nfs_direct_request twice in a row. The source of this is when we have our commit requests to submit, we process them and send them off, and then in the completion path for the commit requests we have if (nfs_commit_end(cinfo.mds)) nfs_direct_write_complete(dreq); However since we're submitting asynchronous requests we sometimes have one that completes before we submit the next one, so we end up calling complete on the nfs_direct_request twice. The only other place we use nfs_generic_commit_list() is in __nfs_commit_inode, which wraps this call in a nfs_commit_begin(); nfs_commit_end(); Which is a common pattern for this style of completion handling, one that is also repeated in the direct code with get_dreq()/put_dreq() calls around where we process events as well as in the completion paths. Fix this by using the same pattern for the commit requests. Before with my 200 node rocksdb stress running this warning would pop every 10ish minutes. With my patch the stress test has been running for several hours without popping. Signed-off-by: Josef Bacik Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin

NFS: Fix data corruption caused by congestion.

2024-03-06T14:48:42+00:00

when AOP_WRITEPAGE_ACTIVATE is returned (as NFS does when it detects congestion) it is important that the folio is redirtied. nfs_writepage_locked() doesn't do this, so files can become corrupted as writes can be lost. Note that this is not needed in v6.8 as AOP_WRITEPAGE_ACTIVATE cannot be returned. It is needed for kernels v5.18..v6.7. Prior to 6.3 the patch is different as it needs to mention "page", not "folio". Reported-and-tested-by: Jacek Tomaka Fixes: 6df25e58532b ("nfs: remove reliance on bdi congestion") Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman

NFS: Fix potential oops in nfs_inode_remove_request()

2023-10-11T15:09:56+00:00

Once a folio's private data has been cleared, it's possible for another process to clear the folio->mapping (e.g. via invalidate_complete_folio2 or evict_mapping_folio), so it wouldn't be safe to call nfs_page_to_inode() after that. Fixes: 0c493b5cf16e ("NFS: Convert buffered writes to use folios") Signed-off-by: Scott Mayhew Reviewed-by: Benjamin Coddington Tested-by: Benjamin Coddington Reviewed-by: Jeff Layton Signed-off-by: Anna Schumaker

nfs: decrement nrequests counter before releasing the req

2023-09-28T16:22:25+00:00

I hit this panic in testing: [ 6235.500016] run fstests generic/464 at 2023-09-18 22:51:24 [ 6288.410761] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 6288.412174] #PF: supervisor read access in kernel mode [ 6288.413160] #PF: error_code(0x0000) - not-present page [ 6288.413992] PGD 0 P4D 0 [ 6288.414603] Oops: 0000 [#1] PREEMPT SMP PTI [ 6288.415419] CPU: 0 PID: 340798 Comm: kworker/u18:8 Not tainted 6.6.0-rc1-gdcf620ceebac #95 [ 6288.416538] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 [ 6288.417701] Workqueue: nfsiod rpc_async_release [sunrpc] [ 6288.418676] RIP: 0010:nfs_inode_remove_request+0xc8/0x150 [nfs] [ 6288.419836] Code: ff ff 48 8b 43 38 48 8b 7b 10 a8 04 74 5b 48 85 ff 74 56 48 8b 07 a9 00 00 08 00 74 58 48 8b 07 f6 c4 10 74 50 e8 c8 44 b3 d5 <48> 8b 00 f0 48 ff 88 30 ff ff ff 5b 5d 41 5c c3 cc cc cc cc 48 8b [ 6288.422389] RSP: 0018:ffffbd618353bda8 EFLAGS: 00010246 [ 6288.423234] RAX: 0000000000000000 RBX: ffff9a29f9a25280 RCX: 0000000000000000 [ 6288.424351] RDX: ffff9a29f9a252b4 RSI: 000000000000000b RDI: ffffef41448e3840 [ 6288.425345] RBP: ffffef41448e3840 R08: 0000000000000038 R09: ffffffffffffffff [ 6288.426334] R10: 0000000000033f80 R11: ffff9a2a7fffa000 R12: ffff9a29093f98c4 [ 6288.427353] R13: 0000000000000000 R14: ffff9a29230f62e0 R15: ffff9a29230f62d0 [ 6288.428358] FS: 0000000000000000(0000) GS:ffff9a2a77c00000(0000) knlGS:0000000000000000 [ 6288.429513] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 6288.430427] CR2: 0000000000000000 CR3: 0000000264748002 CR4: 0000000000770ef0 [ 6288.431553] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 6288.432715] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 6288.433698] PKRU: 55555554 [ 6288.434196] Call Trace: [ 6288.434667] [ 6288.435132] ? __die+0x1f/0x70 [ 6288.435723] ? page_fault_oops+0x159/0x450 [ 6288.436389] ? try_to_wake_up+0x98/0x5d0 [ 6288.437044] ? do_user_addr_fault+0x65/0x660 [ 6288.437728] ? exc_page_fault+0x7a/0x180 [ 6288.438368] ? asm_exc_page_fault+0x22/0x30 [ 6288.439137] ? nfs_inode_remove_request+0xc8/0x150 [nfs] [ 6288.440112] ? nfs_inode_remove_request+0xa0/0x150 [nfs] [ 6288.440924] nfs_commit_release_pages+0x16e/0x340 [nfs] [ 6288.441700] ? __pfx_call_transmit+0x10/0x10 [sunrpc] [ 6288.442475] ? _raw_spin_lock_irqsave+0x23/0x50 [ 6288.443161] nfs_commit_release+0x15/0x40 [nfs] [ 6288.443926] rpc_free_task+0x36/0x60 [sunrpc] [ 6288.444741] rpc_async_release+0x29/0x40 [sunrpc] [ 6288.445509] process_one_work+0x171/0x340 [ 6288.446135] worker_thread+0x277/0x3a0 [ 6288.446724] ? __pfx_worker_thread+0x10/0x10 [ 6288.447376] kthread+0xf0/0x120 [ 6288.447903] ? __pfx_kthread+0x10/0x10 [ 6288.448500] ret_from_fork+0x2d/0x50 [ 6288.449078] ? __pfx_kthread+0x10/0x10 [ 6288.449665] ret_from_fork_asm+0x1b/0x30 [ 6288.450283] [ 6288.450688] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace sunrpc nls_iso8859_1 nls_cp437 vfat fat 9p netfs ext4 kvm_intel crc16 mbcache jbd2 joydev kvm xfs irqbypass virtio_net pcspkr net_failover psmouse failover 9pnet_virtio cirrus drm_shmem_helper virtio_balloon drm_kms_helper button evdev drm loop dm_mod zram zsmalloc crct10dif_pclmul crc32_pclmul ghash_clmulni_intel sha512_ssse3 sha512_generic virtio_blk nvme aesni_intel crypto_simd cryptd nvme_core t10_pi i6300esb crc64_rocksoft_generic crc64_rocksoft crc64 virtio_pci virtio virtio_pci_legacy_dev virtio_pci_modern_dev virtio_ring serio_raw btrfs blake2b_generic libcrc32c crc32c_generic crc32c_intel xor raid6_pq autofs4 [ 6288.460211] CR2: 0000000000000000 [ 6288.460787] ---[ end trace 0000000000000000 ]--- [ 6288.461571] RIP: 0010:nfs_inode_remove_request+0xc8/0x150 [nfs] [ 6288.462500] Code: ff ff 48 8b 43 38 48 8b 7b 10 a8 04 74 5b 48 85 ff 74 56 48 8b 07 a9 00 00 08 00 74 58 48 8b 07 f6 c4 10 74 50 e8 c8 44 b3 d5 <48> 8b 00 f0 48 ff 88 30 ff ff ff 5b 5d 41 5c c3 cc cc cc cc 48 8b [ 6288.465136] RSP: 0018:ffffbd618353bda8 EFLAGS: 00010246 [ 6288.465963] RAX: 0000000000000000 RBX: ffff9a29f9a25280 RCX: 0000000000000000 [ 6288.467035] RDX: ffff9a29f9a252b4 RSI: 000000000000000b RDI: ffffef41448e3840 [ 6288.468093] RBP: ffffef41448e3840 R08: 0000000000000038 R09: ffffffffffffffff [ 6288.469121] R10: 0000000000033f80 R11: ffff9a2a7fffa000 R12: ffff9a29093f98c4 [ 6288.470109] R13: 0000000000000000 R14: ffff9a29230f62e0 R15: ffff9a29230f62d0 [ 6288.471106] FS: 0000000000000000(0000) GS:ffff9a2a77c00000(0000) knlGS:0000000000000000 [ 6288.472216] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 6288.473059] CR2: 0000000000000000 CR3: 0000000264748002 CR4: 0000000000770ef0 [ 6288.474096] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 6288.475097] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 6288.476148] PKRU: 55555554 [ 6288.476665] note: kworker/u18:8[340798] exited with irqs disabled Once we've released "req", it's not safe to dereference it anymore. Decrement the nrequests counter before dropping the reference. Signed-off-by: Jeff Layton Reviewed-by: Benjamin Coddington Tested-by: Benjamin Coddington Signed-off-by: Anna Schumaker

NFS: Use the correct commit info in nfs_join_page_group()

2023-09-13T15:51:11+00:00

Ensure that nfs_clear_request_commit() updates the correct counters when it removes them from the commit list. Fixes: ed5d588fe47f ("NFS: Try to join page groups before an O_DIRECT retransmission") Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker