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FAILED: patch "[PATCH] wifi: mac80211: Discard Beacon frames to non-broadcast" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

2 days, 2 hours

FAILED: patch "[PATCH] lockd: fix vfs_test_lock() calls" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x a49a2a1baa0c553c3548a1c414b6a3c005a8deba # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010559-plaster-snowsuit-aa37@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a49a2a1baa0c553c3548a1c414b6a3c005a8deba Mon Sep 17 00:00:00 2001 From: NeilBrown <neil(a)brown.name> Date: Sat, 22 Nov 2025 12:00:36 +1100 Subject: [PATCH] lockd: fix vfs_test_lock() calls Usage of vfs_test_lock() is somewhat confused. Documentation suggests it is given a "lock" but this is not the case. It is given a struct file_lock which contains some details of the sort of lock it should be looking for. In particular passing a "file_lock" containing fl_lmops or fl_ops is meaningless and possibly confusing. This is particularly problematic in lockd. nlmsvc_testlock() receives an initialised "file_lock" from xdr-decode, including manager ops and an owner. It then mistakenly passes this to vfs_test_lock() which might replace the owner and the ops. This can lead to confusion when freeing the lock. The primary role of the 'struct file_lock' passed to vfs_test_lock() is to report a conflicting lock that was found, so it makes more sense for nlmsvc_testlock() to pass "conflock", which it uses for returning the conflicting lock. With this change, freeing of the lock is not confused and code in __nlm4svc_proc_test() and __nlmsvc_proc_test() can be simplified. Documentation for vfs_test_lock() is improved to reflect its real purpose, and a WARN_ON_ONCE() is added to avoid a similar problem in the future. Reported-by: Olga Kornievskaia <okorniev(a)redhat.com> Closes: https://lore.kernel.org/all/20251021130506.45065-1-okorniev@redhat.com Signed-off-by: NeilBrown <neil(a)brown.name> Fixes: 20fa19027286 ("nfs: add export operations") Cc: stable(a)vger.kernel.org Reviewed-by: Jeff Layton <jlayton(a)kernel.org> Signed-off-by: Chuck Lever <chuck.lever(a)oracle.com> diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c index 109e5caae8c7..4b6f18d97734 100644 --- a/fs/lockd/svc4proc.c +++ b/fs/lockd/svc4proc.c @@ -97,7 +97,6 @@ __nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) struct nlm_args *argp = rqstp->rq_argp; struct nlm_host *host; struct nlm_file *file; - struct nlm_lockowner *test_owner; __be32 rc = rpc_success; dprintk("lockd: TEST4 called\n"); @@ -107,7 +106,6 @@ __nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) if ((resp->status = nlm4svc_retrieve_args(rqstp, argp, &host, &file))) return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success; - test_owner = argp->lock.fl.c.flc_owner; /* Now check for conflicting locks */ resp->status = nlmsvc_testlock(rqstp, file, host, &argp->lock, &resp->lock); @@ -116,7 +114,7 @@ __nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) else dprintk("lockd: TEST4 status %d\n", ntohl(resp->status)); - nlmsvc_put_lockowner(test_owner); + nlmsvc_release_lockowner(&argp->lock); nlmsvc_release_host(host); nlm_release_file(file); return rc; diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c index 3a3d05cfe09a..6bce19fd024c 100644 --- a/fs/lockd/svclock.c +++ b/fs/lockd/svclock.c @@ -633,7 +633,13 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file, } mode = lock_to_openmode(&lock->fl); - error = vfs_test_lock(file->f_file[mode], &lock->fl); + locks_init_lock(&conflock->fl); + /* vfs_test_lock only uses start, end, and owner, but tests flc_file */ + conflock->fl.c.flc_file = lock->fl.c.flc_file; + conflock->fl.fl_start = lock->fl.fl_start; + conflock->fl.fl_end = lock->fl.fl_end; + conflock->fl.c.flc_owner = lock->fl.c.flc_owner; + error = vfs_test_lock(file->f_file[mode], &conflock->fl); if (error) { /* We can't currently deal with deferred test requests */ if (error == FILE_LOCK_DEFERRED) @@ -643,22 +649,19 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file, goto out; } - if (lock->fl.c.flc_type == F_UNLCK) { + if (conflock->fl.c.flc_type == F_UNLCK) { ret = nlm_granted; goto out; } dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", - lock->fl.c.flc_type, (long long)lock->fl.fl_start, - (long long)lock->fl.fl_end); + conflock->fl.c.flc_type, (long long)conflock->fl.fl_start, + (long long)conflock->fl.fl_end); conflock->caller = "somehost"; /* FIXME */ conflock->len = strlen(conflock->caller); conflock->oh.len = 0; /* don't return OH info */ - conflock->svid = lock->fl.c.flc_pid; - conflock->fl.c.flc_type = lock->fl.c.flc_type; - conflock->fl.fl_start = lock->fl.fl_start; - conflock->fl.fl_end = lock->fl.fl_end; - locks_release_private(&lock->fl); + conflock->svid = conflock->fl.c.flc_pid; + locks_release_private(&conflock->fl); ret = nlm_lck_denied; out: diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c index f53d5177f267..5817ef272332 100644 --- a/fs/lockd/svcproc.c +++ b/fs/lockd/svcproc.c @@ -117,7 +117,6 @@ __nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) struct nlm_args *argp = rqstp->rq_argp; struct nlm_host *host; struct nlm_file *file; - struct nlm_lockowner *test_owner; __be32 rc = rpc_success; dprintk("lockd: TEST called\n"); @@ -127,8 +126,6 @@ __nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) if ((resp->status = nlmsvc_retrieve_args(rqstp, argp, &host, &file))) return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success; - test_owner = argp->lock.fl.c.flc_owner; - /* Now check for conflicting locks */ resp->status = cast_status(nlmsvc_testlock(rqstp, file, host, &argp->lock, &resp->lock)); @@ -138,7 +135,7 @@ __nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) dprintk("lockd: TEST status %d vers %d\n", ntohl(resp->status), rqstp->rq_vers); - nlmsvc_put_lockowner(test_owner); + nlmsvc_release_lockowner(&argp->lock); nlmsvc_release_host(host); nlm_release_file(file); return rc; diff --git a/fs/locks.c b/fs/locks.c index 04a3f0e20724..bf5e0d05a026 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -2185,13 +2185,21 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) /** * vfs_test_lock - test file byte range lock * @filp: The file to test lock for - * @fl: The lock to test; also used to hold result + * @fl: The byte-range in the file to test; also used to hold result * + * On entry, @fl does not contain a lock, but identifies a range (fl_start, fl_end) + * in the file (c.flc_file), and an owner (c.flc_owner) for whom existing locks + * should be ignored. c.flc_type and c.flc_flags are ignored. + * Both fl_lmops and fl_ops in @fl must be NULL. * Returns -ERRNO on failure. Indicates presence of conflicting lock by - * setting conf->fl_type to something other than F_UNLCK. + * setting fl->fl_type to something other than F_UNLCK. + * + * If vfs_test_lock() does find a lock and return it, the caller must + * use locks_free_lock() or locks_release_private() on the returned lock. */ int vfs_test_lock(struct file *filp, struct file_lock *fl) { + WARN_ON_ONCE(fl->fl_ops || fl->fl_lmops); WARN_ON_ONCE(filp != fl->c.flc_file); if (filp->f_op->lock) return filp->f_op->lock(filp, F_GETLK, fl);

2 days, 2 hours

FAILED: patch "[PATCH] mptcp: ensure context reset on disconnect()" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

2 days, 2 hours

FAILED: patch "[PATCH] mm: consider non-anon swap cache folios in" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

2 days, 2 hours

FAILED: patch "[PATCH] mptcp: ensure context reset on disconnect()" failed to apply to 6.18-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y git checkout FETCH_HEAD git cherry-pick -x 86730ac255b0497a272704de9a1df559f5d6602e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010548-scotch-cardboard-13c7@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 86730ac255b0497a272704de9a1df559f5d6602e Mon Sep 17 00:00:00 2001 From: Paolo Abeni <pabeni(a)redhat.com> Date: Fri, 12 Dec 2025 13:54:04 +0100 Subject: [PATCH] mptcp: ensure context reset on disconnect() After the blamed commit below, if the MPC subflow is already in TCP_CLOSE status or has fallback to TCP at mptcp_disconnect() time, mptcp_do_fastclose() skips setting the `send_fastclose flag` and the later __mptcp_close_ssk() does not reset anymore the related subflow context. Any later connection will be created with both the `request_mptcp` flag and the msk-level fallback status off (it is unconditionally cleared at MPTCP disconnect time), leading to a warning in subflow_data_ready(): WARNING: CPU: 26 PID: 8996 at net/mptcp/subflow.c:1519 subflow_data_ready (net/mptcp/subflow.c:1519 (discriminator 13)) Modules linked in: CPU: 26 UID: 0 PID: 8996 Comm: syz.22.39 Not tainted 6.18.0-rc7-05427-g11fc074f6c36 #1 PREEMPT(voluntary) Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 RIP: 0010:subflow_data_ready (net/mptcp/subflow.c:1519 (discriminator 13)) Code: 90 0f 0b 90 90 e9 04 fe ff ff e8 b7 1e f5 fe 89 ee bf 07 00 00 00 e8 db 19 f5 fe 83 fd 07 0f 84 35 ff ff ff e8 9d 1e f5 fe 90 <0f> 0b 90 e9 27 ff ff ff e8 8f 1e f5 fe 4c 89 e7 48 89 de e8 14 09 RSP: 0018:ffffc9002646fb30 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff88813b218000 RCX: ffffffff825c8435 RDX: ffff8881300b3580 RSI: ffffffff825c8443 RDI: 0000000000000005 RBP: 000000000000000b R08: ffffffff825c8435 R09: 000000000000000b R10: 0000000000000005 R11: 0000000000000007 R12: ffff888131ac0000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f88330af6c0(0000) GS:ffff888a93dd2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f88330aefe8 CR3: 000000010ff59000 CR4: 0000000000350ef0 Call Trace: <TASK> tcp_data_ready (net/ipv4/tcp_input.c:5356) tcp_data_queue (net/ipv4/tcp_input.c:5445) tcp_rcv_state_process (net/ipv4/tcp_input.c:7165) tcp_v4_do_rcv (net/ipv4/tcp_ipv4.c:1955) __release_sock (include/net/sock.h:1158 (discriminator 6) net/core/sock.c:3180 (discriminator 6)) release_sock (net/core/sock.c:3737) mptcp_sendmsg (net/mptcp/protocol.c:1763 net/mptcp/protocol.c:1857) inet_sendmsg (net/ipv4/af_inet.c:853 (discriminator 7)) __sys_sendto (net/socket.c:727 (discriminator 15) net/socket.c:742 (discriminator 15) net/socket.c:2244 (discriminator 15)) __x64_sys_sendto (net/socket.c:2247) do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1)) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) RIP: 0033:0x7f883326702d Address the issue setting an explicit `fastclosing` flag at fastclose time, and checking such flag after mptcp_do_fastclose(). Fixes: ae155060247b ("mptcp: fix duplicate reset on fastclose") Cc: stable(a)vger.kernel.org Signed-off-by: Paolo Abeni <pabeni(a)redhat.com> Reviewed-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> Link: https://patch.msgid.link/20251212-net-mptcp-subflow_data_ready-warn-v1-2-d1… Signed-off-by: Paolo Abeni <pabeni(a)redhat.com> diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 9b1fafd87cb9..f505b780f713 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2467,10 +2467,10 @@ bool __mptcp_retransmit_pending_data(struct sock *sk) */ static void __mptcp_subflow_disconnect(struct sock *ssk, struct mptcp_subflow_context *subflow, - unsigned int flags) + bool fastclosing) { if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) || - subflow->send_fastclose) { + fastclosing) { /* The MPTCP code never wait on the subflow sockets, TCP-level * disconnect should never fail */ @@ -2538,7 +2538,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk); if (!dispose_it) { - __mptcp_subflow_disconnect(ssk, subflow, flags); + __mptcp_subflow_disconnect(ssk, subflow, msk->fastclosing); release_sock(ssk); goto out; @@ -2884,6 +2884,7 @@ static void mptcp_do_fastclose(struct sock *sk) mptcp_set_state(sk, TCP_CLOSE); mptcp_backlog_purge(sk); + msk->fastclosing = 1; /* Explicitly send the fastclose reset as need */ if (__mptcp_check_fallback(msk)) @@ -3418,6 +3419,7 @@ static int mptcp_disconnect(struct sock *sk, int flags) msk->bytes_sent = 0; msk->bytes_retrans = 0; msk->rcvspace_init = 0; + msk->fastclosing = 0; /* for fallback's sake */ WRITE_ONCE(msk->ack_seq, 0); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index bed0c9aa28b6..66e973500791 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -320,7 +320,8 @@ struct mptcp_sock { fastopening:1, in_accept_queue:1, free_first:1, - rcvspace_init:1; + rcvspace_init:1, + fastclosing:1; u32 notsent_lowat; int keepalive_cnt; int keepalive_idle;

2 days, 4 hours

FAILED: patch "[PATCH] mm/page_alloc: change all pageblocks migrate type on" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 7838a4eb8a1d23160bd3f588ea7f2b8f7c00c55b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010526-crux-caddy-a1e3@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 7838a4eb8a1d23160bd3f588ea7f2b8f7c00c55b Mon Sep 17 00:00:00 2001 From: Alexander Gordeev <agordeev(a)linux.ibm.com> Date: Fri, 12 Dec 2025 16:14:57 +0100 Subject: [PATCH] mm/page_alloc: change all pageblocks migrate type on coalescing When a page is freed it coalesces with a buddy into a higher order page while possible. When the buddy page migrate type differs, it is expected to be updated to match the one of the page being freed. However, only the first pageblock of the buddy page is updated, while the rest of the pageblocks are left unchanged. That causes warnings in later expand() and other code paths (like below), since an inconsistency between migration type of the list containing the page and the page-owned pageblocks migration types is introduced. [ 308.986589] ------------[ cut here ]------------ [ 308.987227] page type is 0, passed migratetype is 1 (nr=256) [ 308.987275] WARNING: CPU: 1 PID: 5224 at mm/page_alloc.c:812 expand+0x23c/0x270 [ 308.987293] Modules linked in: algif_hash(E) af_alg(E) nft_fib_inet(E) nft_fib_ipv4(E) nft_fib_ipv6(E) nft_fib(E) nft_reject_inet(E) nf_reject_ipv4(E) nf_reject_ipv6(E) nft_reject(E) nft_ct(E) nft_chain_nat(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E) nf_tables(E) s390_trng(E) vfio_ccw(E) mdev(E) vfio_iommu_type1(E) vfio(E) sch_fq_codel(E) drm(E) i2c_core(E) drm_panel_orientation_quirks(E) loop(E) nfnetlink(E) vsock_loopback(E) vmw_vsock_virtio_transport_common(E) vsock(E) ctcm(E) fsm(E) diag288_wdt(E) watchdog(E) zfcp(E) scsi_transport_fc(E) ghash_s390(E) prng(E) aes_s390(E) des_generic(E) des_s390(E) libdes(E) sha3_512_s390(E) sha3_256_s390(E) sha_common(E) paes_s390(E) crypto_engine(E) pkey_cca(E) pkey_ep11(E) zcrypt(E) rng_core(E) pkey_pckmo(E) pkey(E) autofs4(E) [ 308.987439] Unloaded tainted modules: hmac_s390(E):2 [ 308.987650] CPU: 1 UID: 0 PID: 5224 Comm: mempig_verify Kdump: loaded Tainted: G E 6.18.0-gcc-bpf-debug #431 PREEMPT [ 308.987657] Tainted: [E]=UNSIGNED_MODULE [ 308.987661] Hardware name: IBM 3906 M04 704 (z/VM 7.3.0) [ 308.987666] Krnl PSW : 0404f00180000000 00000349976fa600 (expand+0x240/0x270) [ 308.987676] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:3 PM:0 RI:0 EA:3 [ 308.987682] Krnl GPRS: 0000034980000004 0000000000000005 0000000000000030 000003499a0e6d88 [ 308.987688] 0000000000000005 0000034980000005 000002be803ac000 0000023efe6c8300 [ 308.987692] 0000000000000008 0000034998d57290 000002be00000100 0000023e00000008 [ 308.987696] 0000000000000000 0000000000000000 00000349976fa5fc 000002c99b1eb6f0 [ 308.987708] Krnl Code: 00000349976fa5f0: c020008a02f2 larl %r2,000003499883abd4 00000349976fa5f6: c0e5ffe3f4b5 brasl %r14,0000034997378f60 #00000349976fa5fc: af000000 mc 0,0 >00000349976fa600: a7f4ff4c brc 15,00000349976fa498 00000349976fa604: b9040026 lgr %r2,%r6 00000349976fa608: c0300088317f larl %r3,0000034998800906 00000349976fa60e: c0e5fffdb6e1 brasl %r14,00000349976b13d0 00000349976fa614: af000000 mc 0,0 [ 308.987734] Call Trace: [ 308.987738] [<00000349976fa600>] expand+0x240/0x270 [ 308.987744] ([<00000349976fa5fc>] expand+0x23c/0x270) [ 308.987749] [<00000349976ff95e>] rmqueue_bulk+0x71e/0x940 [ 308.987754] [<00000349976ffd7e>] __rmqueue_pcplist+0x1fe/0x2a0 [ 308.987759] [<0000034997700966>] rmqueue.isra.0+0xb46/0xf40 [ 308.987763] [<0000034997703ec8>] get_page_from_freelist+0x198/0x8d0 [ 308.987768] [<0000034997706fa8>] __alloc_frozen_pages_noprof+0x198/0x400 [ 308.987774] [<00000349977536f8>] alloc_pages_mpol+0xb8/0x220 [ 308.987781] [<0000034997753bf6>] folio_alloc_mpol_noprof+0x26/0xc0 [ 308.987786] [<0000034997753e4c>] vma_alloc_folio_noprof+0x6c/0xa0 [ 308.987791] [<0000034997775b22>] vma_alloc_anon_folio_pmd+0x42/0x240 [ 308.987799] [<000003499777bfea>] __do_huge_pmd_anonymous_page+0x3a/0x210 [ 308.987804] [<00000349976cb08e>] __handle_mm_fault+0x4de/0x500 [ 308.987809] [<00000349976cb14c>] handle_mm_fault+0x9c/0x3a0 [ 308.987813] [<000003499734d70e>] do_exception+0x1de/0x540 [ 308.987822] [<0000034998387390>] __do_pgm_check+0x130/0x220 [ 308.987830] [<000003499839a934>] pgm_check_handler+0x114/0x160 [ 308.987838] 3 locks held by mempig_verify/5224: [ 308.987842] #0: 0000023ea44c1e08 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0xb2/0x2a0 [ 308.987859] #1: 0000023ee4d41b18 (&pcp->lock){+.+.}-{2:2}, at: rmqueue.isra.0+0xad6/0xf40 [ 308.987871] #2: 0000023efe6c8998 (&zone->lock){..-.}-{2:2}, at: rmqueue_bulk+0x5a/0x940 [ 308.987886] Last Breaking-Event-Address: [ 308.987890] [<0000034997379096>] __warn_printk+0x136/0x140 [ 308.987897] irq event stamp: 52330356 [ 308.987901] hardirqs last enabled at (52330355): [<000003499838742e>] __do_pgm_check+0x1ce/0x220 [ 308.987907] hardirqs last disabled at (52330356): [<000003499839932e>] _raw_spin_lock_irqsave+0x9e/0xe0 [ 308.987913] softirqs last enabled at (52329882): [<0000034997383786>] handle_softirqs+0x2c6/0x530 [ 308.987922] softirqs last disabled at (52329859): [<0000034997382f86>] __irq_exit_rcu+0x126/0x140 [ 308.987929] ---[ end trace 0000000000000000 ]--- [ 308.987936] ------------[ cut here ]------------ [ 308.987940] page type is 0, passed migratetype is 1 (nr=256) [ 308.987951] WARNING: CPU: 1 PID: 5224 at mm/page_alloc.c:860 __del_page_from_free_list+0x1be/0x1e0 [ 308.987960] Modules linked in: algif_hash(E) af_alg(E) nft_fib_inet(E) nft_fib_ipv4(E) nft_fib_ipv6(E) nft_fib(E) nft_reject_inet(E) nf_reject_ipv4(E) nf_reject_ipv6(E) nft_reject(E) nft_ct(E) nft_chain_nat(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E) nf_tables(E) s390_trng(E) vfio_ccw(E) mdev(E) vfio_iommu_type1(E) vfio(E) sch_fq_codel(E) drm(E) i2c_core(E) drm_panel_orientation_quirks(E) loop(E) nfnetlink(E) vsock_loopback(E) vmw_vsock_virtio_transport_common(E) vsock(E) ctcm(E) fsm(E) diag288_wdt(E) watchdog(E) zfcp(E) scsi_transport_fc(E) ghash_s390(E) prng(E) aes_s390(E) des_generic(E) des_s390(E) libdes(E) sha3_512_s390(E) sha3_256_s390(E) sha_common(E) paes_s390(E) crypto_engine(E) pkey_cca(E) pkey_ep11(E) zcrypt(E) rng_core(E) pkey_pckmo(E) pkey(E) autofs4(E) [ 308.988070] Unloaded tainted modules: hmac_s390(E):2 [ 308.988087] CPU: 1 UID: 0 PID: 5224 Comm: mempig_verify Kdump: loaded Tainted: G W E 6.18.0-gcc-bpf-debug #431 PREEMPT [ 308.988095] Tainted: [W]=WARN, [E]=UNSIGNED_MODULE [ 308.988100] Hardware name: IBM 3906 M04 704 (z/VM 7.3.0) [ 308.988105] Krnl PSW : 0404f00180000000 00000349976f9e32 (__del_page_from_free_list+0x1c2/0x1e0) [ 308.988118] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:3 PM:0 RI:0 EA:3 [ 308.988127] Krnl GPRS: 0000034980000004 0000000000000005 0000000000000030 000003499a0e6d88 [ 308.988133] 0000000000000005 0000034980000005 0000034998d57290 0000023efe6c8300 [ 308.988139] 0000000000000001 0000000000000008 000002be00000100 000002be803ac000 [ 308.988144] 0000000000000000 0000000000000001 00000349976f9e2e 000002c99b1eb728 [ 308.988153] Krnl Code: 00000349976f9e22: c020008a06d9 larl %r2,000003499883abd4 00000349976f9e28: c0e5ffe3f89c brasl %r14,0000034997378f60 #00000349976f9e2e: af000000 mc 0,0 >00000349976f9e32: a7f4ff4e brc 15,00000349976f9cce 00000349976f9e36: b904002b lgr %r2,%r11 00000349976f9e3a: c030008a06e7 larl %r3,000003499883ac08 00000349976f9e40: c0e5fffdbac8 brasl %r14,00000349976b13d0 00000349976f9e46: af000000 mc 0,0 [ 308.988184] Call Trace: [ 308.988188] [<00000349976f9e32>] __del_page_from_free_list+0x1c2/0x1e0 [ 308.988195] ([<00000349976f9e2e>] __del_page_from_free_list+0x1be/0x1e0) [ 308.988202] [<00000349976ff946>] rmqueue_bulk+0x706/0x940 [ 308.988208] [<00000349976ffd7e>] __rmqueue_pcplist+0x1fe/0x2a0 [ 308.988214] [<0000034997700966>] rmqueue.isra.0+0xb46/0xf40 [ 308.988221] [<0000034997703ec8>] get_page_from_freelist+0x198/0x8d0 [ 308.988227] [<0000034997706fa8>] __alloc_frozen_pages_noprof+0x198/0x400 [ 308.988233] [<00000349977536f8>] alloc_pages_mpol+0xb8/0x220 [ 308.988240] [<0000034997753bf6>] folio_alloc_mpol_noprof+0x26/0xc0 [ 308.988247] [<0000034997753e4c>] vma_alloc_folio_noprof+0x6c/0xa0 [ 308.988253] [<0000034997775b22>] vma_alloc_anon_folio_pmd+0x42/0x240 [ 308.988260] [<000003499777bfea>] __do_huge_pmd_anonymous_page+0x3a/0x210 [ 308.988267] [<00000349976cb08e>] __handle_mm_fault+0x4de/0x500 [ 308.988273] [<00000349976cb14c>] handle_mm_fault+0x9c/0x3a0 [ 308.988279] [<000003499734d70e>] do_exception+0x1de/0x540 [ 308.988286] [<0000034998387390>] __do_pgm_check+0x130/0x220 [ 308.988293] [<000003499839a934>] pgm_check_handler+0x114/0x160 [ 308.988300] 3 locks held by mempig_verify/5224: [ 308.988305] #0: 0000023ea44c1e08 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0xb2/0x2a0 [ 308.988322] #1: 0000023ee4d41b18 (&pcp->lock){+.+.}-{2:2}, at: rmqueue.isra.0+0xad6/0xf40 [ 308.988334] #2: 0000023efe6c8998 (&zone->lock){..-.}-{2:2}, at: rmqueue_bulk+0x5a/0x940 [ 308.988346] Last Breaking-Event-Address: [ 308.988350] [<0000034997379096>] __warn_printk+0x136/0x140 [ 308.988356] irq event stamp: 52330356 [ 308.988360] hardirqs last enabled at (52330355): [<000003499838742e>] __do_pgm_check+0x1ce/0x220 [ 308.988366] hardirqs last disabled at (52330356): [<000003499839932e>] _raw_spin_lock_irqsave+0x9e/0xe0 [ 308.988373] softirqs last enabled at (52329882): [<0000034997383786>] handle_softirqs+0x2c6/0x530 [ 308.988380] softirqs last disabled at (52329859): [<0000034997382f86>] __irq_exit_rcu+0x126/0x140 [ 308.988388] ---[ end trace 0000000000000000 ]--- Link: https://lkml.kernel.org/r/20251215081002.3353900A9c-agordeev@linux.ibm.com Link: https://lkml.kernel.org/r/20251212151457.3898073Add-agordeev@linux.ibm.com Fixes: e6cf9e1c4cde ("mm: page_alloc: fix up block types when merging compatible blocks") Signed-off-by: Alexander Gordeev <agordeev(a)linux.ibm.com> Reported-by: Marc Hartmayer <mhartmay(a)linux.ibm.com> Closes: https://lore.kernel.org/linux-mm/87wmalyktd.fsf@linux.ibm.com/ Acked-by: Vlastimil Babka <vbabka(a)suse.cz> Acked-by: Johannes Weiner <hannes(a)cmpxchg.org> Reviewed-by: Wei Yang <richard.weiyang(a)gmail.com> Cc: Marc Hartmayer <mhartmay(a)linux.ibm.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 822e05f1a964..f6586f165b89 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -914,6 +914,17 @@ buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn, NULL) != NULL; } +static void change_pageblock_range(struct page *pageblock_page, + int start_order, int migratetype) +{ + int nr_pageblocks = 1 << (start_order - pageblock_order); + + while (nr_pageblocks--) { + set_pageblock_migratetype(pageblock_page, migratetype); + pageblock_page += pageblock_nr_pages; + } +} + /* * Freeing function for a buddy system allocator. * @@ -1000,7 +1011,7 @@ static inline void __free_one_page(struct page *page, * expand() down the line puts the sub-blocks * on the right freelists. */ - set_pageblock_migratetype(buddy, migratetype); + change_pageblock_range(buddy, order, migratetype); } combined_pfn = buddy_pfn & pfn; @@ -2147,17 +2158,6 @@ bool pageblock_unisolate_and_move_free_pages(struct zone *zone, struct page *pag #endif /* CONFIG_MEMORY_ISOLATION */ -static void change_pageblock_range(struct page *pageblock_page, - int start_order, int migratetype) -{ - int nr_pageblocks = 1 << (start_order - pageblock_order); - - while (nr_pageblocks--) { - set_pageblock_migratetype(pageblock_page, migratetype); - pageblock_page += pageblock_nr_pages; - } -} - static inline bool boost_watermark(struct zone *zone) { unsigned long max_boost;

2 days, 5 hours

FAILED: patch "[PATCH] lockd: fix vfs_test_lock() calls" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x a49a2a1baa0c553c3548a1c414b6a3c005a8deba # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010559-outthink-mutilated-30df@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a49a2a1baa0c553c3548a1c414b6a3c005a8deba Mon Sep 17 00:00:00 2001 From: NeilBrown <neil(a)brown.name> Date: Sat, 22 Nov 2025 12:00:36 +1100 Subject: [PATCH] lockd: fix vfs_test_lock() calls Usage of vfs_test_lock() is somewhat confused. Documentation suggests it is given a "lock" but this is not the case. It is given a struct file_lock which contains some details of the sort of lock it should be looking for. In particular passing a "file_lock" containing fl_lmops or fl_ops is meaningless and possibly confusing. This is particularly problematic in lockd. nlmsvc_testlock() receives an initialised "file_lock" from xdr-decode, including manager ops and an owner. It then mistakenly passes this to vfs_test_lock() which might replace the owner and the ops. This can lead to confusion when freeing the lock. The primary role of the 'struct file_lock' passed to vfs_test_lock() is to report a conflicting lock that was found, so it makes more sense for nlmsvc_testlock() to pass "conflock", which it uses for returning the conflicting lock. With this change, freeing of the lock is not confused and code in __nlm4svc_proc_test() and __nlmsvc_proc_test() can be simplified. Documentation for vfs_test_lock() is improved to reflect its real purpose, and a WARN_ON_ONCE() is added to avoid a similar problem in the future. Reported-by: Olga Kornievskaia <okorniev(a)redhat.com> Closes: https://lore.kernel.org/all/20251021130506.45065-1-okorniev@redhat.com Signed-off-by: NeilBrown <neil(a)brown.name> Fixes: 20fa19027286 ("nfs: add export operations") Cc: stable(a)vger.kernel.org Reviewed-by: Jeff Layton <jlayton(a)kernel.org> Signed-off-by: Chuck Lever <chuck.lever(a)oracle.com> diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c index 109e5caae8c7..4b6f18d97734 100644 --- a/fs/lockd/svc4proc.c +++ b/fs/lockd/svc4proc.c @@ -97,7 +97,6 @@ __nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) struct nlm_args *argp = rqstp->rq_argp; struct nlm_host *host; struct nlm_file *file; - struct nlm_lockowner *test_owner; __be32 rc = rpc_success; dprintk("lockd: TEST4 called\n"); @@ -107,7 +106,6 @@ __nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) if ((resp->status = nlm4svc_retrieve_args(rqstp, argp, &host, &file))) return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success; - test_owner = argp->lock.fl.c.flc_owner; /* Now check for conflicting locks */ resp->status = nlmsvc_testlock(rqstp, file, host, &argp->lock, &resp->lock); @@ -116,7 +114,7 @@ __nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) else dprintk("lockd: TEST4 status %d\n", ntohl(resp->status)); - nlmsvc_put_lockowner(test_owner); + nlmsvc_release_lockowner(&argp->lock); nlmsvc_release_host(host); nlm_release_file(file); return rc; diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c index 3a3d05cfe09a..6bce19fd024c 100644 --- a/fs/lockd/svclock.c +++ b/fs/lockd/svclock.c @@ -633,7 +633,13 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file, } mode = lock_to_openmode(&lock->fl); - error = vfs_test_lock(file->f_file[mode], &lock->fl); + locks_init_lock(&conflock->fl); + /* vfs_test_lock only uses start, end, and owner, but tests flc_file */ + conflock->fl.c.flc_file = lock->fl.c.flc_file; + conflock->fl.fl_start = lock->fl.fl_start; + conflock->fl.fl_end = lock->fl.fl_end; + conflock->fl.c.flc_owner = lock->fl.c.flc_owner; + error = vfs_test_lock(file->f_file[mode], &conflock->fl); if (error) { /* We can't currently deal with deferred test requests */ if (error == FILE_LOCK_DEFERRED) @@ -643,22 +649,19 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file, goto out; } - if (lock->fl.c.flc_type == F_UNLCK) { + if (conflock->fl.c.flc_type == F_UNLCK) { ret = nlm_granted; goto out; } dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", - lock->fl.c.flc_type, (long long)lock->fl.fl_start, - (long long)lock->fl.fl_end); + conflock->fl.c.flc_type, (long long)conflock->fl.fl_start, + (long long)conflock->fl.fl_end); conflock->caller = "somehost"; /* FIXME */ conflock->len = strlen(conflock->caller); conflock->oh.len = 0; /* don't return OH info */ - conflock->svid = lock->fl.c.flc_pid; - conflock->fl.c.flc_type = lock->fl.c.flc_type; - conflock->fl.fl_start = lock->fl.fl_start; - conflock->fl.fl_end = lock->fl.fl_end; - locks_release_private(&lock->fl); + conflock->svid = conflock->fl.c.flc_pid; + locks_release_private(&conflock->fl); ret = nlm_lck_denied; out: diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c index f53d5177f267..5817ef272332 100644 --- a/fs/lockd/svcproc.c +++ b/fs/lockd/svcproc.c @@ -117,7 +117,6 @@ __nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) struct nlm_args *argp = rqstp->rq_argp; struct nlm_host *host; struct nlm_file *file; - struct nlm_lockowner *test_owner; __be32 rc = rpc_success; dprintk("lockd: TEST called\n"); @@ -127,8 +126,6 @@ __nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) if ((resp->status = nlmsvc_retrieve_args(rqstp, argp, &host, &file))) return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success; - test_owner = argp->lock.fl.c.flc_owner; - /* Now check for conflicting locks */ resp->status = cast_status(nlmsvc_testlock(rqstp, file, host, &argp->lock, &resp->lock)); @@ -138,7 +135,7 @@ __nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp) dprintk("lockd: TEST status %d vers %d\n", ntohl(resp->status), rqstp->rq_vers); - nlmsvc_put_lockowner(test_owner); + nlmsvc_release_lockowner(&argp->lock); nlmsvc_release_host(host); nlm_release_file(file); return rc; diff --git a/fs/locks.c b/fs/locks.c index 04a3f0e20724..bf5e0d05a026 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -2185,13 +2185,21 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) /** * vfs_test_lock - test file byte range lock * @filp: The file to test lock for - * @fl: The lock to test; also used to hold result + * @fl: The byte-range in the file to test; also used to hold result * + * On entry, @fl does not contain a lock, but identifies a range (fl_start, fl_end) + * in the file (c.flc_file), and an owner (c.flc_owner) for whom existing locks + * should be ignored. c.flc_type and c.flc_flags are ignored. + * Both fl_lmops and fl_ops in @fl must be NULL. * Returns -ERRNO on failure. Indicates presence of conflicting lock by - * setting conf->fl_type to something other than F_UNLCK. + * setting fl->fl_type to something other than F_UNLCK. + * + * If vfs_test_lock() does find a lock and return it, the caller must + * use locks_free_lock() or locks_release_private() on the returned lock. */ int vfs_test_lock(struct file *filp, struct file_lock *fl) { + WARN_ON_ONCE(fl->fl_ops || fl->fl_lmops); WARN_ON_ONCE(filp != fl->c.flc_file); if (filp->f_op->lock) return filp->f_op->lock(filp, F_GETLK, fl);

2 days, 5 hours

[PATCH v2] rust: Add -fdiagnostics-show-context to bindgen_skip_c_flags

by Siddhesh Poyarekar

This got added with: 7454048db27d6 ("kbuild: Enable GCC diagnostic context for value-tracking warnings") but clang does not have this option, so avoid passing it to bindgen. Cc: stable(a)vger.kernel.org Fixes: 7454048db27d6 ("kbuild: Enable GCC diagnostic context for value-tracking warnings") Signed-off-by: Siddhesh Poyarekar <siddhesh(a)gotplt.org> --- rust/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/rust/Makefile b/rust/Makefile index 5d357dce1704..4dcc2eff51cb 100644 --- a/rust/Makefile +++ b/rust/Makefile @@ -383,6 +383,7 @@ bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \ -fno-inline-functions-called-once -fsanitize=bounds-strict \ -fstrict-flex-arrays=% -fmin-function-alignment=% \ -fzero-init-padding-bits=% -mno-fdpic \ + -fdiagnostics-show-context -fdiagnostics-show-context=% \ --param=% --param asan-% -fno-isolate-erroneous-paths-dereference # Derived from `scripts/Makefile.clang`. -- 2.52.0

2 days, 5 hours

[PATCH RESEND v3 4/4] mm/hugetlb: fix excessive IPI broadcasts when unsharing PMD tables using mmu_gather

by David Hildenbrand (Red Hat)

As reported, ever since commit 1013af4f585f ("mm/hugetlb: fix huge_pmd_unshare() vs GUP-fast race") we can end up in some situations where we perform so many IPI broadcasts when unsharing hugetlb PMD page tables that it severely regresses some workloads. In particular, when we fork()+exit(), or when we munmap() a large area backed by many shared PMD tables, we perform one IPI broadcast per unshared PMD table. There are two optimizations to be had: (1) When we process (unshare) multiple such PMD tables, such as during exit(), it is sufficient to send a single IPI broadcast (as long as we respect locking rules) instead of one per PMD table. Locking prevents that any of these PMD tables could get reused before we drop the lock. (2) When we are not the last sharer (> 2 users including us), there is no need to send the IPI broadcast. The shared PMD tables cannot become exclusive (fully unshared) before an IPI will be broadcasted by the last sharer. Concurrent GUP-fast could walk into a PMD table just before we unshared it. It could then succeed in grabbing a page from the shared page table even after munmap() etc succeeded (and supressed an IPI). But there is not difference compared to GUP-fast just sleeping for a while after grabbing the page and re-enabling IRQs. Most importantly, GUP-fast will never walk into page tables that are no-longer shared, because the last sharer will issue an IPI broadcast. (if ever required, checking whether the PUD changed in GUP-fast after grabbing the page like we do in the PTE case could handle this) So let's rework PMD sharing TLB flushing + IPI sync to use the mmu_gather infrastructure so we can implement these optimizations and demystify the code at least a bit. Extend the mmu_gather infrastructure to be able to deal with our special hugetlb PMD table sharing implementation. To make initialization of the mmu_gather easier when working on a single VMA (in particular, when dealing with hugetlb), provide tlb_gather_mmu_vma(). We'll consolidate the handling for (full) unsharing of PMD tables in tlb_unshare_pmd_ptdesc() and tlb_flush_unshared_tables(), and track in "struct mmu_gather" whether we had (full) unsharing of PMD tables. Because locking is very special (concurrent unsharing+reuse must be prevented), we disallow deferring flushing to tlb_finish_mmu() and instead require an explicit earlier call to tlb_flush_unshared_tables(). From hugetlb code, we call huge_pmd_unshare_flush() where we make sure that the expected lock protecting us from concurrent unsharing+reuse is still held. Check with a VM_WARN_ON_ONCE() in tlb_finish_mmu() that tlb_flush_unshared_tables() was properly called earlier. Document it all properly. Notes about tlb_remove_table_sync_one() interaction with unsharing: There are two fairly tricky things: (1) tlb_remove_table_sync_one() is a NOP on architectures without CONFIG_MMU_GATHER_RCU_TABLE_FREE. Here, the assumption is that the previous TLB flush would send an IPI to all relevant CPUs. Careful: some architectures like x86 only send IPIs to all relevant CPUs when tlb->freed_tables is set. The relevant architectures should be selecting MMU_GATHER_RCU_TABLE_FREE, but x86 might not do that in stable kernels and it might have been problematic before this patch. Also, the arch flushing behavior (independent of IPIs) is different when tlb->freed_tables is set. Do we have to enlighten them to also take care of tlb->unshared_tables? So far we didn't care, so hopefully we are fine. Of course, we could be setting tlb->freed_tables as well, but that might then unnecessarily flush too much, because the semantics of tlb->freed_tables are a bit fuzzy. This patch changes nothing in this regard. (2) tlb_remove_table_sync_one() is not a NOP on architectures with CONFIG_MMU_GATHER_RCU_TABLE_FREE that actually don't need a sync. Take x86 as an example: in the common case (!pv, !X86_FEATURE_INVLPGB) we still issue IPIs during TLB flushes and don't actually need the second tlb_remove_table_sync_one(). This optimized can be implemented on top of this, by checking e.g., in tlb_remove_table_sync_one() whether we really need IPIs. But as described in (1), it really must honor tlb->freed_tables then to send IPIs to all relevant CPUs. Notes on TLB flushing changes: (1) Flushing for non-shared PMD tables We're converting from flush_hugetlb_tlb_range() to tlb_remove_huge_tlb_entry(). Given that we properly initialize the MMU gather in tlb_gather_mmu_vma() to be hugetlb aware, similar to __unmap_hugepage_range(), that should be fine. (2) Flushing for shared PMD tables We're converting from various things (flush_hugetlb_tlb_range(), tlb_flush_pmd_range(), flush_tlb_range()) to tlb_flush_pmd_range(). tlb_flush_pmd_range() achieves the same that tlb_remove_huge_tlb_entry() would achieve in these scenarios. Note that tlb_remove_huge_tlb_entry() also calls __tlb_remove_tlb_entry(), however that is only implemented on powerpc, which does not support PMD table sharing. Similar to (1), tlb_gather_mmu_vma() should make sure that TLB flushing keeps on working as expected. Further, note that the ptdesc_pmd_pts_dec() in huge_pmd_share() is not a concern, as we are holding the i_mmap_lock the whole time, preventing concurrent unsharing. That ptdesc_pmd_pts_dec() usage will be removed separately as a cleanup later. There are plenty more cleanups to be had, but they have to wait until this is fixed. Fixes: 1013af4f585f ("mm/hugetlb: fix huge_pmd_unshare() vs GUP-fast race") Reported-by: Uschakow, Stanislav" <suschako(a)amazon.de> Closes: https://lore.kernel.org/all/4d3878531c76479d9f8ca9789dc6485d@amazon.de/ Tested-by: Laurence Oberman <loberman(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: David Hildenbrand (Red Hat) <david(a)kernel.org> --- include/asm-generic/tlb.h | 77 +++++++++++++++++++++++- include/linux/hugetlb.h | 15 +++-- include/linux/mm_types.h | 1 + mm/hugetlb.c | 123 ++++++++++++++++++++++---------------- mm/mmu_gather.c | 33 ++++++++++ mm/rmap.c | 25 +++++--- 6 files changed, 208 insertions(+), 66 deletions(-) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 1fff717cae510..4d679d2a206b4 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -46,7 +46,8 @@ * * The mmu_gather API consists of: * - * - tlb_gather_mmu() / tlb_gather_mmu_fullmm() / tlb_finish_mmu() + * - tlb_gather_mmu() / tlb_gather_mmu_fullmm() / tlb_gather_mmu_vma() / + * tlb_finish_mmu() * * start and finish a mmu_gather * @@ -364,6 +365,20 @@ struct mmu_gather { unsigned int vma_huge : 1; unsigned int vma_pfn : 1; + /* + * Did we unshare (unmap) any shared page tables? For now only + * used for hugetlb PMD table sharing. + */ + unsigned int unshared_tables : 1; + + /* + * Did we unshare any page tables such that they are now exclusive + * and could get reused+modified by the new owner? When setting this + * flag, "unshared_tables" will be set as well. For now only used + * for hugetlb PMD table sharing. + */ + unsigned int fully_unshared_tables : 1; + unsigned int batch_count; #ifndef CONFIG_MMU_GATHER_NO_GATHER @@ -400,6 +415,7 @@ static inline void __tlb_reset_range(struct mmu_gather *tlb) tlb->cleared_pmds = 0; tlb->cleared_puds = 0; tlb->cleared_p4ds = 0; + tlb->unshared_tables = 0; /* * Do not reset mmu_gather::vma_* fields here, we do not * call into tlb_start_vma() again to set them if there is an @@ -484,7 +500,7 @@ static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) * these bits. */ if (!(tlb->freed_tables || tlb->cleared_ptes || tlb->cleared_pmds || - tlb->cleared_puds || tlb->cleared_p4ds)) + tlb->cleared_puds || tlb->cleared_p4ds || tlb->unshared_tables)) return; tlb_flush(tlb); @@ -773,6 +789,63 @@ static inline bool huge_pmd_needs_flush(pmd_t oldpmd, pmd_t newpmd) } #endif +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING +static inline void tlb_unshare_pmd_ptdesc(struct mmu_gather *tlb, struct ptdesc *pt, + unsigned long addr) +{ + /* + * The caller must make sure that concurrent unsharing + exclusive + * reuse is impossible until tlb_flush_unshared_tables() was called. + */ + VM_WARN_ON_ONCE(!ptdesc_pmd_is_shared(pt)); + ptdesc_pmd_pts_dec(pt); + + /* Clearing a PUD pointing at a PMD table with PMD leaves. */ + tlb_flush_pmd_range(tlb, addr & PUD_MASK, PUD_SIZE); + + /* + * If the page table is now exclusively owned, we fully unshared + * a page table. + */ + if (!ptdesc_pmd_is_shared(pt)) + tlb->fully_unshared_tables = true; + tlb->unshared_tables = true; +} + +static inline void tlb_flush_unshared_tables(struct mmu_gather *tlb) +{ + /* + * As soon as the caller drops locks to allow for reuse of + * previously-shared tables, these tables could get modified and + * even reused outside of hugetlb context, so we have to make sure that + * any page table walkers (incl. TLB, GUP-fast) are aware of that + * change. + * + * Even if we are not fully unsharing a PMD table, we must + * flush the TLB for the unsharer now. + */ + if (tlb->unshared_tables) + tlb_flush_mmu_tlbonly(tlb); + + /* + * Similarly, we must make sure that concurrent GUP-fast will not + * walk previously-shared page tables that are getting modified+reused + * elsewhere. So broadcast an IPI to wait for any concurrent GUP-fast. + * + * We only perform this when we are the last sharer of a page table, + * as the IPI will reach all CPUs: any GUP-fast. + * + * Note that on configs where tlb_remove_table_sync_one() is a NOP, + * the expectation is that the tlb_flush_mmu_tlbonly() would have issued + * required IPIs already for us. + */ + if (tlb->fully_unshared_tables) { + tlb_remove_table_sync_one(); + tlb->fully_unshared_tables = false; + } +} +#endif /* CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */ + #endif /* CONFIG_MMU */ #endif /* _ASM_GENERIC__TLB_H */ diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 03c8725efa289..e51b8ef0cebd9 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -240,8 +240,9 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz); unsigned long hugetlb_mask_last_page(struct hstate *h); -int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep); +int huge_pmd_unshare(struct mmu_gather *tlb, struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep); +void huge_pmd_unshare_flush(struct mmu_gather *tlb, struct vm_area_struct *vma); void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, unsigned long *start, unsigned long *end); @@ -300,13 +301,17 @@ static inline struct address_space *hugetlb_folio_mapping_lock_write( return NULL; } -static inline int huge_pmd_unshare(struct mm_struct *mm, - struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep) +static inline int huge_pmd_unshare(struct mmu_gather *tlb, + struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) { return 0; } +static inline void huge_pmd_unshare_flush(struct mmu_gather *tlb, + struct vm_area_struct *vma) +{ +} + static inline void adjust_range_if_pmd_sharing_possible( struct vm_area_struct *vma, unsigned long *start, unsigned long *end) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 42af2292951d4..d1053b2c1f800 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1522,6 +1522,7 @@ static inline unsigned int mm_cid_size(void) struct mmu_gather; extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm); extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm); +void tlb_gather_mmu_vma(struct mmu_gather *tlb, struct vm_area_struct *vma); extern void tlb_finish_mmu(struct mmu_gather *tlb); struct vm_fault; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 3c77cdef12a32..2609b6d58f99e 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5096,7 +5096,7 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, unsigned long last_addr_mask; pte_t *src_pte, *dst_pte; struct mmu_notifier_range range; - bool shared_pmd = false; + struct mmu_gather tlb; mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, old_addr, old_end); @@ -5106,6 +5106,7 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, * range. */ flush_cache_range(vma, range.start, range.end); + tlb_gather_mmu_vma(&tlb, vma); mmu_notifier_invalidate_range_start(&range); last_addr_mask = hugetlb_mask_last_page(h); @@ -5122,8 +5123,7 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, if (huge_pte_none(huge_ptep_get(mm, old_addr, src_pte))) continue; - if (huge_pmd_unshare(mm, vma, old_addr, src_pte)) { - shared_pmd = true; + if (huge_pmd_unshare(&tlb, vma, old_addr, src_pte)) { old_addr |= last_addr_mask; new_addr |= last_addr_mask; continue; @@ -5134,15 +5134,16 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, break; move_huge_pte(vma, old_addr, new_addr, src_pte, dst_pte, sz); + tlb_remove_huge_tlb_entry(h, &tlb, src_pte, old_addr); } - if (shared_pmd) - flush_hugetlb_tlb_range(vma, range.start, range.end); - else - flush_hugetlb_tlb_range(vma, old_end - len, old_end); + tlb_flush_mmu_tlbonly(&tlb); + huge_pmd_unshare_flush(&tlb, vma); + mmu_notifier_invalidate_range_end(&range); i_mmap_unlock_write(mapping); hugetlb_vma_unlock_write(vma); + tlb_finish_mmu(&tlb); return len + old_addr - old_end; } @@ -5161,7 +5162,6 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long sz = huge_page_size(h); bool adjust_reservation; unsigned long last_addr_mask; - bool force_flush = false; WARN_ON(!is_vm_hugetlb_page(vma)); BUG_ON(start & ~huge_page_mask(h)); @@ -5184,10 +5184,8 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, } ptl = huge_pte_lock(h, mm, ptep); - if (huge_pmd_unshare(mm, vma, address, ptep)) { + if (huge_pmd_unshare(tlb, vma, address, ptep)) { spin_unlock(ptl); - tlb_flush_pmd_range(tlb, address & PUD_MASK, PUD_SIZE); - force_flush = true; address |= last_addr_mask; continue; } @@ -5303,14 +5301,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, } tlb_end_vma(tlb, vma); - /* - * There is nothing protecting a previously-shared page table that we - * unshared through huge_pmd_unshare() from getting freed after we - * release i_mmap_rwsem, so flush the TLB now. If huge_pmd_unshare() - * succeeded, flush the range corresponding to the pud. - */ - if (force_flush) - tlb_flush_mmu_tlbonly(tlb); + huge_pmd_unshare_flush(tlb, vma); } void __hugetlb_zap_begin(struct vm_area_struct *vma, @@ -6409,11 +6400,11 @@ long hugetlb_change_protection(struct vm_area_struct *vma, pte_t pte; struct hstate *h = hstate_vma(vma); long pages = 0, psize = huge_page_size(h); - bool shared_pmd = false; struct mmu_notifier_range range; unsigned long last_addr_mask; bool uffd_wp = cp_flags & MM_CP_UFFD_WP; bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; + struct mmu_gather tlb; /* * In the case of shared PMDs, the area to flush could be beyond @@ -6426,6 +6417,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma, BUG_ON(address >= end); flush_cache_range(vma, range.start, range.end); + tlb_gather_mmu_vma(&tlb, vma); mmu_notifier_invalidate_range_start(&range); hugetlb_vma_lock_write(vma); @@ -6452,7 +6444,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma, } } ptl = huge_pte_lock(h, mm, ptep); - if (huge_pmd_unshare(mm, vma, address, ptep)) { + if (huge_pmd_unshare(&tlb, vma, address, ptep)) { /* * When uffd-wp is enabled on the vma, unshare * shouldn't happen at all. Warn about it if it @@ -6461,7 +6453,6 @@ long hugetlb_change_protection(struct vm_area_struct *vma, WARN_ON_ONCE(uffd_wp || uffd_wp_resolve); pages++; spin_unlock(ptl); - shared_pmd = true; address |= last_addr_mask; continue; } @@ -6522,22 +6513,16 @@ long hugetlb_change_protection(struct vm_area_struct *vma, pte = huge_pte_clear_uffd_wp(pte); huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte); pages++; + tlb_remove_huge_tlb_entry(h, &tlb, ptep, address); } next: spin_unlock(ptl); cond_resched(); } - /* - * There is nothing protecting a previously-shared page table that we - * unshared through huge_pmd_unshare() from getting freed after we - * release i_mmap_rwsem, so flush the TLB now. If huge_pmd_unshare() - * succeeded, flush the range corresponding to the pud. - */ - if (shared_pmd) - flush_hugetlb_tlb_range(vma, range.start, range.end); - else - flush_hugetlb_tlb_range(vma, start, end); + + tlb_flush_mmu_tlbonly(&tlb); + huge_pmd_unshare_flush(&tlb, vma); /* * No need to call mmu_notifier_arch_invalidate_secondary_tlbs() we are * downgrading page table protection not changing it to point to a new @@ -6548,6 +6533,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma, i_mmap_unlock_write(vma->vm_file->f_mapping); hugetlb_vma_unlock_write(vma); mmu_notifier_invalidate_range_end(&range); + tlb_finish_mmu(&tlb); return pages > 0 ? (pages << h->order) : pages; } @@ -6904,18 +6890,27 @@ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, return pte; } -/* - * unmap huge page backed by shared pte. +/** + * huge_pmd_unshare - Unmap a pmd table if it is shared by multiple users + * @tlb: the current mmu_gather. + * @vma: the vma covering the pmd table. + * @addr: the address we are trying to unshare. + * @ptep: pointer into the (pmd) page table. + * + * Called with the page table lock held, the i_mmap_rwsem held in write mode + * and the hugetlb vma lock held in write mode. * - * Called with page table lock held. + * Note: The caller must call huge_pmd_unshare_flush() before dropping the + * i_mmap_rwsem. * - * returns: 1 successfully unmapped a shared pte page - * 0 the underlying pte page is not shared, or it is the last user + * Returns: 1 if it was a shared PMD table and it got unmapped, or 0 if it + * was not a shared PMD table. */ -int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep) +int huge_pmd_unshare(struct mmu_gather *tlb, struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) { unsigned long sz = huge_page_size(hstate_vma(vma)); + struct mm_struct *mm = vma->vm_mm; pgd_t *pgd = pgd_offset(mm, addr); p4d_t *p4d = p4d_offset(pgd, addr); pud_t *pud = pud_offset(p4d, addr); @@ -6927,18 +6922,36 @@ int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, i_mmap_assert_write_locked(vma->vm_file->f_mapping); hugetlb_vma_assert_locked(vma); pud_clear(pud); - /* - * Once our caller drops the rmap lock, some other process might be - * using this page table as a normal, non-hugetlb page table. - * Wait for pending gup_fast() in other threads to finish before letting - * that happen. - */ - tlb_remove_table_sync_one(); - ptdesc_pmd_pts_dec(virt_to_ptdesc(ptep)); + + tlb_unshare_pmd_ptdesc(tlb, virt_to_ptdesc(ptep), addr); + mm_dec_nr_pmds(mm); return 1; } +/* + * huge_pmd_unshare_flush - Complete a sequence of huge_pmd_unshare() calls + * @tlb: the current mmu_gather. + * @vma: the vma covering the pmd table. + * + * Perform necessary TLB flushes or IPI broadcasts to synchronize PMD table + * unsharing with concurrent page table walkers. + * + * This function must be called after a sequence of huge_pmd_unshare() + * calls while still holding the i_mmap_rwsem. + */ +void huge_pmd_unshare_flush(struct mmu_gather *tlb, struct vm_area_struct *vma) +{ + /* + * We must synchronize page table unsharing such that nobody will + * try reusing a previously-shared page table while it might still + * be in use by previous sharers (TLB, GUP_fast). + */ + i_mmap_assert_write_locked(vma->vm_file->f_mapping); + + tlb_flush_unshared_tables(tlb); +} + #else /* !CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, @@ -6947,12 +6960,16 @@ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, return NULL; } -int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep) +int huge_pmd_unshare(struct mmu_gather *tlb, struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) { return 0; } +void huge_pmd_unshare_flush(struct mmu_gather *tlb, struct vm_area_struct *vma) +{ +} + void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, unsigned long *start, unsigned long *end) { @@ -7219,6 +7236,7 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma, unsigned long sz = huge_page_size(h); struct mm_struct *mm = vma->vm_mm; struct mmu_notifier_range range; + struct mmu_gather tlb; unsigned long address; spinlock_t *ptl; pte_t *ptep; @@ -7230,6 +7248,8 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma, return; flush_cache_range(vma, start, end); + tlb_gather_mmu_vma(&tlb, vma); + /* * No need to call adjust_range_if_pmd_sharing_possible(), because * we have already done the PUD_SIZE alignment. @@ -7248,10 +7268,10 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma, if (!ptep) continue; ptl = huge_pte_lock(h, mm, ptep); - huge_pmd_unshare(mm, vma, address, ptep); + huge_pmd_unshare(&tlb, vma, address, ptep); spin_unlock(ptl); } - flush_hugetlb_tlb_range(vma, start, end); + huge_pmd_unshare_flush(&tlb, vma); if (take_locks) { i_mmap_unlock_write(vma->vm_file->f_mapping); hugetlb_vma_unlock_write(vma); @@ -7261,6 +7281,7 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma, * Documentation/mm/mmu_notifier.rst. */ mmu_notifier_invalidate_range_end(&range); + tlb_finish_mmu(&tlb); } /* diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c index 247e3f9db6c7a..cd32c2dbf501b 100644 --- a/mm/mmu_gather.c +++ b/mm/mmu_gather.c @@ -10,6 +10,7 @@ #include <linux/swap.h> #include <linux/rmap.h> #include <linux/pgalloc.h> +#include <linux/hugetlb.h> #include <asm/tlb.h> @@ -426,6 +427,7 @@ static void __tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, #endif tlb->vma_pfn = 0; + tlb->fully_unshared_tables = 0; __tlb_reset_range(tlb); inc_tlb_flush_pending(tlb->mm); } @@ -459,6 +461,31 @@ void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm) __tlb_gather_mmu(tlb, mm, true); } +/** + * tlb_gather_mmu - initialize an mmu_gather structure for operating on a single + * VMA + * @tlb: the mmu_gather structure to initialize + * @vma: the vm_area_struct + * + * Called to initialize an (on-stack) mmu_gather structure for operating on + * a single VMA. In contrast to tlb_gather_mmu(), calling this function will + * not require another call to tlb_start_vma(). In contrast to tlb_start_vma(), + * this function will *not* call flush_cache_range(). + * + * For hugetlb VMAs, this function will also initialize the mmu_gather + * page_size accordingly, not requiring a separate call to + * tlb_change_page_size(). + * + */ +void tlb_gather_mmu_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) +{ + tlb_gather_mmu(tlb, vma->vm_mm); + tlb_update_vma_flags(tlb, vma); + if (is_vm_hugetlb_page(vma)) + /* All entries have the same size. */ + tlb_change_page_size(tlb, huge_page_size(hstate_vma(vma))); +} + /** * tlb_finish_mmu - finish an mmu_gather structure * @tlb: the mmu_gather structure to finish @@ -468,6 +495,12 @@ void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm) */ void tlb_finish_mmu(struct mmu_gather *tlb) { + /* + * We expect an earlier huge_pmd_unshare_flush() call to sort this out, + * due to complicated locking requirements with page table unsharing. + */ + VM_WARN_ON_ONCE(tlb->fully_unshared_tables); + /* * If there are parallel threads are doing PTE changes on same range * under non-exclusive lock (e.g., mmap_lock read-side) but defer TLB diff --git a/mm/rmap.c b/mm/rmap.c index 748f48727a162..7b9879ef442d9 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -76,7 +76,7 @@ #include <linux/mm_inline.h> #include <linux/oom.h> -#include <asm/tlbflush.h> +#include <asm/tlb.h> #define CREATE_TRACE_POINTS #include <trace/events/migrate.h> @@ -2008,13 +2008,17 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, * if unsuccessful. */ if (!anon) { + struct mmu_gather tlb; + VM_BUG_ON(!(flags & TTU_RMAP_LOCKED)); if (!hugetlb_vma_trylock_write(vma)) goto walk_abort; - if (huge_pmd_unshare(mm, vma, address, pvmw.pte)) { + + tlb_gather_mmu_vma(&tlb, vma); + if (huge_pmd_unshare(&tlb, vma, address, pvmw.pte)) { hugetlb_vma_unlock_write(vma); - flush_tlb_range(vma, - range.start, range.end); + huge_pmd_unshare_flush(&tlb, vma); + tlb_finish_mmu(&tlb); /* * The PMD table was unmapped, * consequently unmapping the folio. @@ -2022,6 +2026,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, goto walk_done; } hugetlb_vma_unlock_write(vma); + tlb_finish_mmu(&tlb); } pteval = huge_ptep_clear_flush(vma, address, pvmw.pte); if (pte_dirty(pteval)) @@ -2398,17 +2403,20 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, * fail if unsuccessful. */ if (!anon) { + struct mmu_gather tlb; + VM_BUG_ON(!(flags & TTU_RMAP_LOCKED)); if (!hugetlb_vma_trylock_write(vma)) { page_vma_mapped_walk_done(&pvmw); ret = false; break; } - if (huge_pmd_unshare(mm, vma, address, pvmw.pte)) { - hugetlb_vma_unlock_write(vma); - flush_tlb_range(vma, - range.start, range.end); + tlb_gather_mmu_vma(&tlb, vma); + if (huge_pmd_unshare(&tlb, vma, address, pvmw.pte)) { + hugetlb_vma_unlock_write(vma); + huge_pmd_unshare_flush(&tlb, vma); + tlb_finish_mmu(&tlb); /* * The PMD table was unmapped, * consequently unmapping the folio. @@ -2417,6 +2425,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, break; } hugetlb_vma_unlock_write(vma); + tlb_finish_mmu(&tlb); } /* Nuke the hugetlb page table entry */ pteval = huge_ptep_clear_flush(vma, address, pvmw.pte); -- 2.52.0

2 days, 6 hours

+ mm-vmscan-fix-demotion-targets-checks-in-reclaim-demotion.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm/vmscan: fix demotion targets checks in reclaim/demotion has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-vmscan-fix-demotion-targets-checks-in-reclaim-demotion.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Bing Jiao <bingjiao(a)google.com> Subject: mm/vmscan: fix demotion targets checks in reclaim/demotion Date: Tue, 6 Jan 2026 07:56:54 +0000 Fix two bugs in demote_folio_list() and can_demote() due to incorrect demotion target checks in reclaim/demotion. Commit 7d709f49babc ("vmscan,cgroup: apply mems_effective to reclaim") introduces the cpuset.mems_effective check and applies it to can_demote(). However: 1. It does not apply this check in demote_folio_list(), which leads to situations where pages are demoted to nodes that are explicitly excluded from the task's cpuset.mems. 2. It checks only the nodes in the immediate next demotion hierarchy and does not check all allowed demotion targets in can_demote(). This can cause pages to never be demoted if the nodes in the next demotion hierarchy are not set in mems_effective. These bugs break resource isolation provided by cpuset.mems. This is visible from userspace because pages can either fail to be demoted entirely or are demoted to nodes that are not allowed in multi-tier memory systems. To address these bugs, update cpuset_node_allowed() and mem_cgroup_node_allowed() to return effective_mems, allowing directly logic-and operation against demotion targets. Also update can_demote() and demote_folio_list() accordingly. Bug 1 reproduction: Assume a system with 4 nodes, where nodes 0-1 are top-tier and nodes 2-3 are far-tier memory. All nodes have equal capacity. Test script: echo 1 > /sys/kernel/mm/numa/demotion_enabled mkdir /sys/fs/cgroup/test echo +cpuset > /sys/fs/cgroup/cgroup.subtree_control echo "0-2" > /sys/fs/cgroup/test/cpuset.mems echo $$ > /sys/fs/cgroup/test/cgroup.procs swapoff -a # Expectation: Should respect node 0-2 limit. # Observation: Node 3 shows significant allocation (MemFree drops) stress-ng --oomable --vm 1 --vm-bytes 150% --mbind 0,1 Bug 2 reproduction: Assume a system with 6 nodes, where nodes 0-2 are top-tier, node 3 is a far-tier node, and nodes 4-5 are the farthest-tier nodes. All nodes have equal capacity. Test script: echo 1 > /sys/kernel/mm/numa/demotion_enabled mkdir /sys/fs/cgroup/test echo +cpuset > /sys/fs/cgroup/cgroup.subtree_control echo "0-2,4-5" > /sys/fs/cgroup/test/cpuset.mems echo $$ > /sys/fs/cgroup/test/cgroup.procs swapoff -a # Expectation: Pages are demoted to Nodes 4-5 # Observation: No pages are demoted before oom. stress-ng --oomable --vm 1 --vm-bytes 150% --mbind 0,1,2 Link: https://lkml.kernel.org/r/20260106075703.1420072-1-bingjiao@google.com Fixes: 7d709f49babc ("vmscan,cgroup: apply mems_effective to reclaim") Signed-off-by: Bing Jiao <bingjiao(a)google.com> Reviewed-by: Gregory Price <gourry(a)gourry.net> Cc: Axel Rasmussen <axelrasmussen(a)google.com> Cc: David Hildenbrand <david(a)kernel.org> Cc: Johannes Weiner <hannes(a)cmpxchg.org> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Michal Hocko <mhocko(a)kernel.org> Cc: "Michal Koutn��" <mkoutny(a)suse.com> Cc: Michal Koutn�� <mkoutny(a)suse.com> Cc: Muchun Song <muchun.song(a)linux.dev> Cc: Qi Zheng <zhengqi.arch(a)bytedance.com> Cc: Roman Gushchin <roman.gushchin(a)linux.dev> Cc: Shakeel Butt <shakeel.butt(a)linux.dev> Cc: Tejun Heo <tj(a)kernel.org> Cc: Waiman Long <longman(a)redhat.com> Cc: Wei Xu <weixugc(a)google.com> Cc: Yuanchu Xie <yuanchu(a)google.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/cpuset.h | 6 +-- include/linux/memcontrol.h | 6 +-- kernel/cgroup/cpuset.c | 54 +++++++++++++++++++++++------------ mm/memcontrol.c | 16 +++++++++- mm/vmscan.c | 30 +++++++++++-------- 5 files changed, 74 insertions(+), 38 deletions(-) --- a/include/linux/cpuset.h~mm-vmscan-fix-demotion-targets-checks-in-reclaim-demotion +++ a/include/linux/cpuset.h @@ -174,7 +174,7 @@ static inline void set_mems_allowed(node task_unlock(current); } -extern bool cpuset_node_allowed(struct cgroup *cgroup, int nid); +extern void cpuset_nodes_allowed(struct cgroup *cgroup, nodemask_t *mask); #else /* !CONFIG_CPUSETS */ static inline bool cpusets_enabled(void) { return false; } @@ -301,9 +301,9 @@ static inline bool read_mems_allowed_ret return false; } -static inline bool cpuset_node_allowed(struct cgroup *cgroup, int nid) +static inline void cpuset_nodes_allowed(struct cgroup *cgroup, nodemask_t *mask) { - return true; + nodes_copy(*mask, node_states[N_MEMORY]); } #endif /* !CONFIG_CPUSETS */ --- a/include/linux/memcontrol.h~mm-vmscan-fix-demotion-targets-checks-in-reclaim-demotion +++ a/include/linux/memcontrol.h @@ -1744,7 +1744,7 @@ static inline void count_objcg_events(st rcu_read_unlock(); } -bool mem_cgroup_node_allowed(struct mem_cgroup *memcg, int nid); +void mem_cgroup_node_filter_allowed(struct mem_cgroup *memcg, nodemask_t *mask); void mem_cgroup_show_protected_memory(struct mem_cgroup *memcg); @@ -1815,9 +1815,9 @@ static inline ino_t page_cgroup_ino(stru return 0; } -static inline bool mem_cgroup_node_allowed(struct mem_cgroup *memcg, int nid) +static inline void mem_cgroup_node_filter_allowed(struct mem_cgroup *memcg, + nodemask_t *mask) { - return true; } static inline void mem_cgroup_show_protected_memory(struct mem_cgroup *memcg) --- a/kernel/cgroup/cpuset.c~mm-vmscan-fix-demotion-targets-checks-in-reclaim-demotion +++ a/kernel/cgroup/cpuset.c @@ -4416,40 +4416,58 @@ bool cpuset_current_node_allowed(int nod return allowed; } -bool cpuset_node_allowed(struct cgroup *cgroup, int nid) +/** + * cpuset_nodes_allowed - return effective_mems mask from a cgroup cpuset. + * @cgroup: pointer to struct cgroup. + * @mask: pointer to struct nodemask_t to be returned. + * + * Returns effective_mems mask from a cgroup cpuset if it is cgroup v2 and + * has cpuset subsys. Otherwise, returns node_states[N_MEMORY]. + * + * This function intentionally avoids taking the cpuset_mutex or callback_lock + * when accessing effective_mems. This is because the obtained effective_mems + * is stale immediately after the query anyway (e.g., effective_mems is updated + * immediately after releasing the lock but before returning). + * + * As a result, returned @mask may be empty because cs->effective_mems can be + * rebound during this call. Besides, nodes in @mask are not guaranteed to be + * online due to hot plugins. Callers should check the mask for validity on + * return based on its subsequent use. + **/ +void cpuset_nodes_allowed(struct cgroup *cgroup, nodemask_t *mask) { struct cgroup_subsys_state *css; struct cpuset *cs; - bool allowed; /* * In v1, mem_cgroup and cpuset are unlikely in the same hierarchy * and mems_allowed is likely to be empty even if we could get to it, - * so return true to avoid taking a global lock on the empty check. + * so return directly to avoid taking a global lock on the empty check. */ - if (!cpuset_v2()) - return true; + if (!cgroup || !cpuset_v2()) { + nodes_copy(*mask, node_states[N_MEMORY]); + return; + } css = cgroup_get_e_css(cgroup, &cpuset_cgrp_subsys); - if (!css) - return true; + if (!css) { + nodes_copy(*mask, node_states[N_MEMORY]); + return; + } /* - * Normally, accessing effective_mems would require the cpuset_mutex - * or callback_lock - but node_isset is atomic and the reference - * taken via cgroup_get_e_css is sufficient to protect css. - * - * Since this interface is intended for use by migration paths, we - * relax locking here to avoid taking global locks - while accepting - * there may be rare scenarios where the result may be innaccurate. + * The reference taken via cgroup_get_e_css is sufficient to + * protect css, but it does not imply safe accesses to effective_mems. * - * Reclaim and migration are subject to these same race conditions, and - * cannot make strong isolation guarantees, so this is acceptable. + * Normally, accessing effective_mems would require the cpuset_mutex + * or callback_lock - but the correctness of this information is stale + * immediately after the query anyway. We do not acquire the lock + * during this process to save lock contention in exchange for racing + * against mems_allowed rebinds. */ cs = container_of(css, struct cpuset, css); - allowed = node_isset(nid, cs->effective_mems); + nodes_copy(*mask, cs->effective_mems); css_put(css); - return allowed; } /** --- a/mm/memcontrol.c~mm-vmscan-fix-demotion-targets-checks-in-reclaim-demotion +++ a/mm/memcontrol.c @@ -5624,9 +5624,21 @@ subsys_initcall(mem_cgroup_swap_init); #endif /* CONFIG_SWAP */ -bool mem_cgroup_node_allowed(struct mem_cgroup *memcg, int nid) +void mem_cgroup_node_filter_allowed(struct mem_cgroup *memcg, nodemask_t *mask) { - return memcg ? cpuset_node_allowed(memcg->css.cgroup, nid) : true; + nodemask_t allowed; + + if (!memcg) + return; + + /* + * Since this interface is intended for use by migration paths, and + * reclaim and migration are subject to race conditions such as changes + * in effective_mems and hot-unpluging of nodes, inaccurate allowed + * mask is acceptable. + */ + cpuset_nodes_allowed(memcg->css.cgroup, &allowed); + nodes_and(*mask, *mask, allowed); } void mem_cgroup_show_protected_memory(struct mem_cgroup *memcg) --- a/mm/vmscan.c~mm-vmscan-fix-demotion-targets-checks-in-reclaim-demotion +++ a/mm/vmscan.c @@ -344,19 +344,21 @@ static void flush_reclaim_state(struct s static bool can_demote(int nid, struct scan_control *sc, struct mem_cgroup *memcg) { - int demotion_nid; + struct pglist_data *pgdat = NODE_DATA(nid); + nodemask_t allowed_mask; - if (!numa_demotion_enabled) + if (!pgdat || !numa_demotion_enabled) return false; if (sc && sc->no_demotion) return false; - demotion_nid = next_demotion_node(nid); - if (demotion_nid == NUMA_NO_NODE) + node_get_allowed_targets(pgdat, &allowed_mask); + if (nodes_empty(allowed_mask)) return false; - /* If demotion node isn't in the cgroup's mems_allowed, fall back */ - return mem_cgroup_node_allowed(memcg, demotion_nid); + /* Filter out nodes that are not in cgroup's mems_allowed. */ + mem_cgroup_node_filter_allowed(memcg, &allowed_mask); + return !nodes_empty(allowed_mask); } static inline bool can_reclaim_anon_pages(struct mem_cgroup *memcg, @@ -1019,7 +1021,8 @@ static struct folio *alloc_demote_folio( * Folios which are not demoted are left on @demote_folios. */ static unsigned int demote_folio_list(struct list_head *demote_folios, - struct pglist_data *pgdat) + struct pglist_data *pgdat, + struct mem_cgroup *memcg) { int target_nid = next_demotion_node(pgdat->node_id); unsigned int nr_succeeded; @@ -1033,7 +1036,6 @@ static unsigned int demote_folio_list(st */ .gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) | __GFP_NOMEMALLOC | GFP_NOWAIT, - .nid = target_nid, .nmask = &allowed_mask, .reason = MR_DEMOTION, }; @@ -1041,10 +1043,14 @@ static unsigned int demote_folio_list(st if (list_empty(demote_folios)) return 0; - if (target_nid == NUMA_NO_NODE) - return 0; - node_get_allowed_targets(pgdat, &allowed_mask); + mem_cgroup_node_filter_allowed(memcg, &allowed_mask); + if (nodes_empty(allowed_mask)) + return false; + + if (!node_isset(target_nid, allowed_mask)) + target_nid = node_random(&allowed_mask); + mtc.nid = target_nid; /* Demotion ignores all cpuset and mempolicy settings */ migrate_pages(demote_folios, alloc_demote_folio, NULL, @@ -1566,7 +1572,7 @@ keep: /* 'folio_list' is always empty here */ /* Migrate folios selected for demotion */ - nr_demoted = demote_folio_list(&demote_folios, pgdat); + nr_demoted = demote_folio_list(&demote_folios, pgdat, memcg); nr_reclaimed += nr_demoted; stat->nr_demoted += nr_demoted; /* Folios that could not be demoted are still in @demote_folios */ _ Patches currently in -mm which might be from bingjiao(a)google.com are mm-vmscan-fix-demotion-targets-checks-in-reclaim-demotion.patch

2 days, 6 hours

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