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FAILED: patch "[PATCH] ksmbd: Prevent integer overflow in calculation of deadtime" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-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-5.15.y git checkout FETCH_HEAD git cherry-pick -x a93ff742820f75bf8bb3fcf21d9f25ca6eb3d4c6 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042134-thriving-decimeter-0201@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a93ff742820f75bf8bb3fcf21d9f25ca6eb3d4c6 Mon Sep 17 00:00:00 2001 From: Denis Arefev <arefev(a)swemel.ru> Date: Wed, 9 Apr 2025 12:04:49 +0300 Subject: [PATCH] ksmbd: Prevent integer overflow in calculation of deadtime The user can set any value for 'deadtime'. This affects the arithmetic expression 'req->deadtime * SMB_ECHO_INTERVAL', which is subject to overflow. The added check makes the server behavior more predictable. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers") Cc: stable(a)vger.kernel.org Signed-off-by: Denis Arefev <arefev(a)swemel.ru> Acked-by: Namjae Jeon <linkinjeon(a)kernel.org> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/server/transport_ipc.c b/fs/smb/server/transport_ipc.c index 3f185ae60dc5..2a3e2b0ce557 100644 --- a/fs/smb/server/transport_ipc.c +++ b/fs/smb/server/transport_ipc.c @@ -310,7 +310,11 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req) server_conf.signing = req->signing; server_conf.tcp_port = req->tcp_port; server_conf.ipc_timeout = req->ipc_timeout * HZ; - server_conf.deadtime = req->deadtime * SMB_ECHO_INTERVAL; + if (check_mul_overflow(req->deadtime, SMB_ECHO_INTERVAL, + &server_conf.deadtime)) { + ret = -EINVAL; + goto out; + } server_conf.share_fake_fscaps = req->share_fake_fscaps; ksmbd_init_domain(req->sub_auth); @@ -337,6 +341,7 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req) server_conf.bind_interfaces_only = req->bind_interfaces_only; ret |= ksmbd_tcp_set_interfaces(KSMBD_STARTUP_CONFIG_INTERFACES(req), req->ifc_list_sz); +out: if (ret) { pr_err("Server configuration error: %s %s %s\n", req->netbios_name, req->server_string,

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FAILED: patch "[PATCH] ksmbd: fix use-after-free in smb_break_all_levII_oplock()" 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 18b4fac5ef17f77fed9417d22210ceafd6525fc7 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042122-stallion-relapse-1076@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 18b4fac5ef17f77fed9417d22210ceafd6525fc7 Mon Sep 17 00:00:00 2001 From: Namjae Jeon <linkinjeon(a)kernel.org> Date: Tue, 15 Apr 2025 09:30:21 +0900 Subject: [PATCH] ksmbd: fix use-after-free in smb_break_all_levII_oplock() There is a room in smb_break_all_levII_oplock that can cause racy issues when unlocking in the middle of the loop. This patch use read lock to protect whole loop. Cc: stable(a)vger.kernel.org Reported-by: Norbert Szetei <norbert(a)doyensec.com> Tested-by: Norbert Szetei <norbert(a)doyensec.com> Signed-off-by: Namjae Jeon <linkinjeon(a)kernel.org> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c index f103b1bd0400..81a29857b1e3 100644 --- a/fs/smb/server/oplock.c +++ b/fs/smb/server/oplock.c @@ -129,14 +129,6 @@ static void free_opinfo(struct oplock_info *opinfo) kfree(opinfo); } -static inline void opinfo_free_rcu(struct rcu_head *rcu_head) -{ - struct oplock_info *opinfo; - - opinfo = container_of(rcu_head, struct oplock_info, rcu_head); - free_opinfo(opinfo); -} - struct oplock_info *opinfo_get(struct ksmbd_file *fp) { struct oplock_info *opinfo; @@ -157,8 +149,8 @@ static struct oplock_info *opinfo_get_list(struct ksmbd_inode *ci) if (list_empty(&ci->m_op_list)) return NULL; - rcu_read_lock(); - opinfo = list_first_or_null_rcu(&ci->m_op_list, struct oplock_info, + down_read(&ci->m_lock); + opinfo = list_first_entry(&ci->m_op_list, struct oplock_info, op_entry); if (opinfo) { if (opinfo->conn == NULL || @@ -171,8 +163,7 @@ static struct oplock_info *opinfo_get_list(struct ksmbd_inode *ci) } } } - - rcu_read_unlock(); + up_read(&ci->m_lock); return opinfo; } @@ -185,7 +176,7 @@ void opinfo_put(struct oplock_info *opinfo) if (!atomic_dec_and_test(&opinfo->refcount)) return; - call_rcu(&opinfo->rcu_head, opinfo_free_rcu); + free_opinfo(opinfo); } static void opinfo_add(struct oplock_info *opinfo) @@ -193,7 +184,7 @@ static void opinfo_add(struct oplock_info *opinfo) struct ksmbd_inode *ci = opinfo->o_fp->f_ci; down_write(&ci->m_lock); - list_add_rcu(&opinfo->op_entry, &ci->m_op_list); + list_add(&opinfo->op_entry, &ci->m_op_list); up_write(&ci->m_lock); } @@ -207,7 +198,7 @@ static void opinfo_del(struct oplock_info *opinfo) write_unlock(&lease_list_lock); } down_write(&ci->m_lock); - list_del_rcu(&opinfo->op_entry); + list_del(&opinfo->op_entry); up_write(&ci->m_lock); } @@ -1347,8 +1338,8 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp, ci = fp->f_ci; op = opinfo_get(fp); - rcu_read_lock(); - list_for_each_entry_rcu(brk_op, &ci->m_op_list, op_entry) { + down_read(&ci->m_lock); + list_for_each_entry(brk_op, &ci->m_op_list, op_entry) { if (brk_op->conn == NULL) continue; @@ -1358,7 +1349,6 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp, if (ksmbd_conn_releasing(brk_op->conn)) continue; - rcu_read_unlock(); if (brk_op->is_lease && (brk_op->o_lease->state & (~(SMB2_LEASE_READ_CACHING_LE | SMB2_LEASE_HANDLE_CACHING_LE)))) { @@ -1388,9 +1378,8 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp, oplock_break(brk_op, SMB2_OPLOCK_LEVEL_NONE, NULL); next: opinfo_put(brk_op); - rcu_read_lock(); } - rcu_read_unlock(); + up_read(&ci->m_lock); if (op) opinfo_put(op); diff --git a/fs/smb/server/oplock.h b/fs/smb/server/oplock.h index 3f64f0787263..9a56eaadd0dd 100644 --- a/fs/smb/server/oplock.h +++ b/fs/smb/server/oplock.h @@ -71,7 +71,6 @@ struct oplock_info { struct list_head lease_entry; wait_queue_head_t oplock_q; /* Other server threads */ wait_queue_head_t oplock_brk; /* oplock breaking wait */ - struct rcu_head rcu_head; }; struct lease_break_info {

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FAILED: patch "[PATCH] ksmbd: fix use-after-free in __smb2_lease_break_noti()" 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 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042110-bovine-triangle-a138@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de Mon Sep 17 00:00:00 2001 From: Namjae Jeon <linkinjeon(a)kernel.org> Date: Fri, 11 Apr 2025 15:19:46 +0900 Subject: [PATCH] ksmbd: fix use-after-free in __smb2_lease_break_noti() Move tcp_transport free to ksmbd_conn_free. If ksmbd connection is referenced when ksmbd server thread terminates, It will not be freed, but conn->tcp_transport is freed. __smb2_lease_break_noti can be performed asynchronously when the connection is disconnected. __smb2_lease_break_noti calls ksmbd_conn_write, which can cause use-after-free when conn->ksmbd_transport is already freed. Cc: stable(a)vger.kernel.org Reported-by: Norbert Szetei <norbert(a)doyensec.com> Tested-by: Norbert Szetei <norbert(a)doyensec.com> Signed-off-by: Namjae Jeon <linkinjeon(a)kernel.org> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c index c1f22c129111..83764c230e9d 100644 --- a/fs/smb/server/connection.c +++ b/fs/smb/server/connection.c @@ -39,8 +39,10 @@ void ksmbd_conn_free(struct ksmbd_conn *conn) xa_destroy(&conn->sessions); kvfree(conn->request_buf); kfree(conn->preauth_info); - if (atomic_dec_and_test(&conn->refcnt)) + if (atomic_dec_and_test(&conn->refcnt)) { + ksmbd_free_transport(conn->transport); kfree(conn); + } } /** diff --git a/fs/smb/server/transport_tcp.c b/fs/smb/server/transport_tcp.c index 7f38a3c3f5bd..abedf510899a 100644 --- a/fs/smb/server/transport_tcp.c +++ b/fs/smb/server/transport_tcp.c @@ -93,15 +93,19 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk) return t; } +void ksmbd_free_transport(struct ksmbd_transport *kt) +{ + struct tcp_transport *t = TCP_TRANS(kt); + + sock_release(t->sock); + kfree(t->iov); + kfree(t); +} + static void free_transport(struct tcp_transport *t) { kernel_sock_shutdown(t->sock, SHUT_RDWR); - sock_release(t->sock); - t->sock = NULL; - ksmbd_conn_free(KSMBD_TRANS(t)->conn); - kfree(t->iov); - kfree(t); } /** diff --git a/fs/smb/server/transport_tcp.h b/fs/smb/server/transport_tcp.h index 8c9aa624cfe3..1e51675ee1b2 100644 --- a/fs/smb/server/transport_tcp.h +++ b/fs/smb/server/transport_tcp.h @@ -8,6 +8,7 @@ int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz); struct interface *ksmbd_find_netdev_name_iface_list(char *netdev_name); +void ksmbd_free_transport(struct ksmbd_transport *kt); int ksmbd_tcp_init(void); void ksmbd_tcp_destroy(void);

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FAILED: patch "[PATCH] ksmbd: fix use-after-free in __smb2_lease_break_noti()" 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 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042109-embroider-consoling-20d9@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de Mon Sep 17 00:00:00 2001 From: Namjae Jeon <linkinjeon(a)kernel.org> Date: Fri, 11 Apr 2025 15:19:46 +0900 Subject: [PATCH] ksmbd: fix use-after-free in __smb2_lease_break_noti() Move tcp_transport free to ksmbd_conn_free. If ksmbd connection is referenced when ksmbd server thread terminates, It will not be freed, but conn->tcp_transport is freed. __smb2_lease_break_noti can be performed asynchronously when the connection is disconnected. __smb2_lease_break_noti calls ksmbd_conn_write, which can cause use-after-free when conn->ksmbd_transport is already freed. Cc: stable(a)vger.kernel.org Reported-by: Norbert Szetei <norbert(a)doyensec.com> Tested-by: Norbert Szetei <norbert(a)doyensec.com> Signed-off-by: Namjae Jeon <linkinjeon(a)kernel.org> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c index c1f22c129111..83764c230e9d 100644 --- a/fs/smb/server/connection.c +++ b/fs/smb/server/connection.c @@ -39,8 +39,10 @@ void ksmbd_conn_free(struct ksmbd_conn *conn) xa_destroy(&conn->sessions); kvfree(conn->request_buf); kfree(conn->preauth_info); - if (atomic_dec_and_test(&conn->refcnt)) + if (atomic_dec_and_test(&conn->refcnt)) { + ksmbd_free_transport(conn->transport); kfree(conn); + } } /** diff --git a/fs/smb/server/transport_tcp.c b/fs/smb/server/transport_tcp.c index 7f38a3c3f5bd..abedf510899a 100644 --- a/fs/smb/server/transport_tcp.c +++ b/fs/smb/server/transport_tcp.c @@ -93,15 +93,19 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk) return t; } +void ksmbd_free_transport(struct ksmbd_transport *kt) +{ + struct tcp_transport *t = TCP_TRANS(kt); + + sock_release(t->sock); + kfree(t->iov); + kfree(t); +} + static void free_transport(struct tcp_transport *t) { kernel_sock_shutdown(t->sock, SHUT_RDWR); - sock_release(t->sock); - t->sock = NULL; - ksmbd_conn_free(KSMBD_TRANS(t)->conn); - kfree(t->iov); - kfree(t); } /** diff --git a/fs/smb/server/transport_tcp.h b/fs/smb/server/transport_tcp.h index 8c9aa624cfe3..1e51675ee1b2 100644 --- a/fs/smb/server/transport_tcp.h +++ b/fs/smb/server/transport_tcp.h @@ -8,6 +8,7 @@ int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz); struct interface *ksmbd_find_netdev_name_iface_list(char *netdev_name); +void ksmbd_free_transport(struct ksmbd_transport *kt); int ksmbd_tcp_init(void); void ksmbd_tcp_destroy(void);

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FAILED: patch "[PATCH] ksmbd: fix use-after-free in __smb2_lease_break_noti()" 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 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042109-uncurled-pebble-1681@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de Mon Sep 17 00:00:00 2001 From: Namjae Jeon <linkinjeon(a)kernel.org> Date: Fri, 11 Apr 2025 15:19:46 +0900 Subject: [PATCH] ksmbd: fix use-after-free in __smb2_lease_break_noti() Move tcp_transport free to ksmbd_conn_free. If ksmbd connection is referenced when ksmbd server thread terminates, It will not be freed, but conn->tcp_transport is freed. __smb2_lease_break_noti can be performed asynchronously when the connection is disconnected. __smb2_lease_break_noti calls ksmbd_conn_write, which can cause use-after-free when conn->ksmbd_transport is already freed. Cc: stable(a)vger.kernel.org Reported-by: Norbert Szetei <norbert(a)doyensec.com> Tested-by: Norbert Szetei <norbert(a)doyensec.com> Signed-off-by: Namjae Jeon <linkinjeon(a)kernel.org> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c index c1f22c129111..83764c230e9d 100644 --- a/fs/smb/server/connection.c +++ b/fs/smb/server/connection.c @@ -39,8 +39,10 @@ void ksmbd_conn_free(struct ksmbd_conn *conn) xa_destroy(&conn->sessions); kvfree(conn->request_buf); kfree(conn->preauth_info); - if (atomic_dec_and_test(&conn->refcnt)) + if (atomic_dec_and_test(&conn->refcnt)) { + ksmbd_free_transport(conn->transport); kfree(conn); + } } /** diff --git a/fs/smb/server/transport_tcp.c b/fs/smb/server/transport_tcp.c index 7f38a3c3f5bd..abedf510899a 100644 --- a/fs/smb/server/transport_tcp.c +++ b/fs/smb/server/transport_tcp.c @@ -93,15 +93,19 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk) return t; } +void ksmbd_free_transport(struct ksmbd_transport *kt) +{ + struct tcp_transport *t = TCP_TRANS(kt); + + sock_release(t->sock); + kfree(t->iov); + kfree(t); +} + static void free_transport(struct tcp_transport *t) { kernel_sock_shutdown(t->sock, SHUT_RDWR); - sock_release(t->sock); - t->sock = NULL; - ksmbd_conn_free(KSMBD_TRANS(t)->conn); - kfree(t->iov); - kfree(t); } /** diff --git a/fs/smb/server/transport_tcp.h b/fs/smb/server/transport_tcp.h index 8c9aa624cfe3..1e51675ee1b2 100644 --- a/fs/smb/server/transport_tcp.h +++ b/fs/smb/server/transport_tcp.h @@ -8,6 +8,7 @@ int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz); struct interface *ksmbd_find_netdev_name_iface_list(char *netdev_name); +void ksmbd_free_transport(struct ksmbd_transport *kt); int ksmbd_tcp_init(void); void ksmbd_tcp_destroy(void);

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FAILED: patch "[PATCH] irqchip/renesas-rzv2h: Prevent TINT spurious interrupt" failed to apply to 6.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.14-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-6.14.y git checkout FETCH_HEAD git cherry-pick -x 28e89cdac6482f3c980df3e2e245db7366269124 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042143-clash-grumbly-11dd@gregkh' --subject-prefix 'PATCH 6.14.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 28e89cdac6482f3c980df3e2e245db7366269124 Mon Sep 17 00:00:00 2001 From: Biju Das <biju.das.jz(a)bp.renesas.com> Date: Tue, 15 Apr 2025 11:33:41 +0100 Subject: [PATCH] irqchip/renesas-rzv2h: Prevent TINT spurious interrupt A spurious TINT interrupt is seen during boot on RZ/G3E SMARC EVK. A glitch in the edge detection circuit can cause a spurious interrupt. Clear the status flag after setting the ICU_TSSRk registers, which is recommended in the hardware manual as a countermeasure. Fixes: 0d7605e75ac2 ("irqchip: Add RZ/V2H(P) Interrupt Control Unit (ICU) driver") Signed-off-by: Biju Das <biju.das.jz(a)bp.renesas.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: stable(a)vger.kernel.org diff --git a/drivers/irqchip/irq-renesas-rzv2h.c b/drivers/irqchip/irq-renesas-rzv2h.c index 3d5b5fdf9bde..0f0fd7d4dfdf 100644 --- a/drivers/irqchip/irq-renesas-rzv2h.c +++ b/drivers/irqchip/irq-renesas-rzv2h.c @@ -170,6 +170,14 @@ static void rzv2h_tint_irq_endisable(struct irq_data *d, bool enable) else tssr &= ~ICU_TSSR_TIEN(tssel_n, priv->info->field_width); writel_relaxed(tssr, priv->base + priv->info->t_offs + ICU_TSSR(k)); + + /* + * A glitch in the edge detection circuit can cause a spurious + * interrupt. Clear the status flag after setting the ICU_TSSRk + * registers, which is recommended by the hardware manual as a + * countermeasure. + */ + writel_relaxed(BIT(tint_nr), priv->base + priv->info->t_offs + ICU_TSCLR); } static void rzv2h_icu_irq_disable(struct irq_data *d)

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FAILED: patch "[PATCH] mm: page_alloc: speed up fallbacks in rmqueue_bulk()" 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 90abee6d7895d5eef18c91d870d8168be4e76e9d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042150-hardiness-hunting-0780@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 90abee6d7895d5eef18c91d870d8168be4e76e9d Mon Sep 17 00:00:00 2001 From: Johannes Weiner <hannes(a)cmpxchg.org> Date: Mon, 7 Apr 2025 14:01:53 -0400 Subject: [PATCH] mm: page_alloc: speed up fallbacks in rmqueue_bulk() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The test robot identified c2f6ea38fc1b ("mm: page_alloc: don't steal single pages from biggest buddy") as the root cause of a 56.4% regression in vm-scalability::lru-file-mmap-read. Carlos reports an earlier patch, c0cd6f557b90 ("mm: page_alloc: fix freelist movement during block conversion"), as the root cause for a regression in worst-case zone->lock+irqoff hold times. Both of these patches modify the page allocator's fallback path to be less greedy in an effort to stave off fragmentation. The flip side of this is that fallbacks are also less productive each time around, which means the fallback search can run much more frequently. Carlos' traces point to rmqueue_bulk() specifically, which tries to refill the percpu cache by allocating a large batch of pages in a loop. It highlights how once the native freelists are exhausted, the fallback code first scans orders top-down for whole blocks to claim, then falls back to a bottom-up search for the smallest buddy to steal. For the next batch page, it goes through the same thing again. This can be made more efficient. Since rmqueue_bulk() holds the zone->lock over the entire batch, the freelists are not subject to outside changes; when the search for a block to claim has already failed, there is no point in trying again for the next page. Modify __rmqueue() to remember the last successful fallback mode, and restart directly from there on the next rmqueue_bulk() iteration. Oliver confirms that this improves beyond the regression that the test robot reported against c2f6ea38fc1b: commit: f3b92176f4 ("tools/selftests: add guard region test for /proc/$pid/pagemap") c2f6ea38fc ("mm: page_alloc: don't steal single pages from biggest buddy") acc4d5ff0b ("Merge tag 'net-6.15-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net") 2c847f27c3 ("mm: page_alloc: speed up fallbacks in rmqueue_bulk()") <--- your patch f3b92176f4f7100f c2f6ea38fc1b640aa7a2e155cc1 acc4d5ff0b61eb1715c498b6536 2c847f27c37da65a93d23c237c5 ---------------- --------------------------- --------------------------- --------------------------- %stddev %change %stddev %change %stddev %change %stddev \ | \ | \ | \ 25525364 ± 3% -56.4% 11135467 -57.8% 10779336 +31.6% 33581409 vm-scalability.throughput Carlos confirms that worst-case times are almost fully recovered compared to before the earlier culprit patch: 2dd482ba627d (before freelist hygiene): 1ms c0cd6f557b90 (after freelist hygiene): 90ms next-20250319 (steal smallest buddy): 280ms this patch : 8ms [jackmanb(a)google.com: comment updates] Link: https://lkml.kernel.org/r/D92AC0P9594X.3BML64MUKTF8Z@google.com [hannes(a)cmpxchg.org: reset rmqueue_mode in rmqueue_buddy() error loop, per Yunsheng Lin] Link: https://lkml.kernel.org/r/20250409140023.GA2313@cmpxchg.org Link: https://lkml.kernel.org/r/20250407180154.63348-1-hannes@cmpxchg.org Fixes: c0cd6f557b90 ("mm: page_alloc: fix freelist movement during block conversion") Fixes: c2f6ea38fc1b ("mm: page_alloc: don't steal single pages from biggest buddy") Signed-off-by: Johannes Weiner <hannes(a)cmpxchg.org> Signed-off-by: Brendan Jackman <jackmanb(a)google.com> Reported-by: kernel test robot <oliver.sang(a)intel.com> Reported-by: Carlos Song <carlos.song(a)nxp.com> Tested-by: Carlos Song <carlos.song(a)nxp.com> Tested-by: kernel test robot <oliver.sang(a)intel.com> Closes: https://lore.kernel.org/oe-lkp/202503271547.fc08b188-lkp@intel.com Reviewed-by: Brendan Jackman <jackmanb(a)google.com> Tested-by: Shivank Garg <shivankg(a)amd.com> Acked-by: Zi Yan <ziy(a)nvidia.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> [6.10+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 9a219fe8e130..1715e34b91af 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2183,23 +2183,15 @@ try_to_claim_block(struct zone *zone, struct page *page, } /* - * Try finding a free buddy page on the fallback list. - * - * This will attempt to claim a whole pageblock for the requested type - * to ensure grouping of such requests in the future. - * - * If a whole block cannot be claimed, steal an individual page, regressing to - * __rmqueue_smallest() logic to at least break up as little contiguity as - * possible. + * Try to allocate from some fallback migratetype by claiming the entire block, + * i.e. converting it to the allocation's start migratetype. * * The use of signed ints for order and current_order is a deliberate * deviation from the rest of this file, to make the for loop * condition simpler. - * - * Return the stolen page, or NULL if none can be found. */ static __always_inline struct page * -__rmqueue_fallback(struct zone *zone, int order, int start_migratetype, +__rmqueue_claim(struct zone *zone, int order, int start_migratetype, unsigned int alloc_flags) { struct free_area *area; @@ -2237,14 +2229,29 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype, page = try_to_claim_block(zone, page, current_order, order, start_migratetype, fallback_mt, alloc_flags); - if (page) - goto got_one; + if (page) { + trace_mm_page_alloc_extfrag(page, order, current_order, + start_migratetype, fallback_mt); + return page; + } } - if (alloc_flags & ALLOC_NOFRAGMENT) - return NULL; + return NULL; +} + +/* + * Try to steal a single page from some fallback migratetype. Leave the rest of + * the block as its current migratetype, potentially causing fragmentation. + */ +static __always_inline struct page * +__rmqueue_steal(struct zone *zone, int order, int start_migratetype) +{ + struct free_area *area; + int current_order; + struct page *page; + int fallback_mt; + bool claim_block; - /* No luck claiming pageblock. Find the smallest fallback page */ for (current_order = order; current_order < NR_PAGE_ORDERS; current_order++) { area = &(zone->free_area[current_order]); fallback_mt = find_suitable_fallback(area, current_order, @@ -2254,25 +2261,28 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype, page = get_page_from_free_area(area, fallback_mt); page_del_and_expand(zone, page, order, current_order, fallback_mt); - goto got_one; + trace_mm_page_alloc_extfrag(page, order, current_order, + start_migratetype, fallback_mt); + return page; } return NULL; - -got_one: - trace_mm_page_alloc_extfrag(page, order, current_order, - start_migratetype, fallback_mt); - - return page; } +enum rmqueue_mode { + RMQUEUE_NORMAL, + RMQUEUE_CMA, + RMQUEUE_CLAIM, + RMQUEUE_STEAL, +}; + /* * Do the hard work of removing an element from the buddy allocator. * Call me with the zone->lock already held. */ static __always_inline struct page * __rmqueue(struct zone *zone, unsigned int order, int migratetype, - unsigned int alloc_flags) + unsigned int alloc_flags, enum rmqueue_mode *mode) { struct page *page; @@ -2291,16 +2301,48 @@ __rmqueue(struct zone *zone, unsigned int order, int migratetype, } } - page = __rmqueue_smallest(zone, order, migratetype); - if (unlikely(!page)) { - if (alloc_flags & ALLOC_CMA) + /* + * First try the freelists of the requested migratetype, then try + * fallbacks modes with increasing levels of fragmentation risk. + * + * The fallback logic is expensive and rmqueue_bulk() calls in + * a loop with the zone->lock held, meaning the freelists are + * not subject to any outside changes. Remember in *mode where + * we found pay dirt, to save us the search on the next call. + */ + switch (*mode) { + case RMQUEUE_NORMAL: + page = __rmqueue_smallest(zone, order, migratetype); + if (page) + return page; + fallthrough; + case RMQUEUE_CMA: + if (alloc_flags & ALLOC_CMA) { page = __rmqueue_cma_fallback(zone, order); - - if (!page) - page = __rmqueue_fallback(zone, order, migratetype, - alloc_flags); + if (page) { + *mode = RMQUEUE_CMA; + return page; + } + } + fallthrough; + case RMQUEUE_CLAIM: + page = __rmqueue_claim(zone, order, migratetype, alloc_flags); + if (page) { + /* Replenished preferred freelist, back to normal mode. */ + *mode = RMQUEUE_NORMAL; + return page; + } + fallthrough; + case RMQUEUE_STEAL: + if (!(alloc_flags & ALLOC_NOFRAGMENT)) { + page = __rmqueue_steal(zone, order, migratetype); + if (page) { + *mode = RMQUEUE_STEAL; + return page; + } + } } - return page; + return NULL; } /* @@ -2312,6 +2354,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, unsigned long count, struct list_head *list, int migratetype, unsigned int alloc_flags) { + enum rmqueue_mode rmqm = RMQUEUE_NORMAL; unsigned long flags; int i; @@ -2323,7 +2366,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, } for (i = 0; i < count; ++i) { struct page *page = __rmqueue(zone, order, migratetype, - alloc_flags); + alloc_flags, &rmqm); if (unlikely(page == NULL)) break; @@ -2948,7 +2991,9 @@ struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone, if (alloc_flags & ALLOC_HIGHATOMIC) page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC); if (!page) { - page = __rmqueue(zone, order, migratetype, alloc_flags); + enum rmqueue_mode rmqm = RMQUEUE_NORMAL; + + page = __rmqueue(zone, order, migratetype, alloc_flags, &rmqm); /* * If the allocation fails, allow OOM handling and

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FAILED: patch "[PATCH] mm: page_alloc: speed up fallbacks in rmqueue_bulk()" failed to apply to 6.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.14-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-6.14.y git checkout FETCH_HEAD git cherry-pick -x 90abee6d7895d5eef18c91d870d8168be4e76e9d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042149-busily-amaretto-e684@gregkh' --subject-prefix 'PATCH 6.14.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 90abee6d7895d5eef18c91d870d8168be4e76e9d Mon Sep 17 00:00:00 2001 From: Johannes Weiner <hannes(a)cmpxchg.org> Date: Mon, 7 Apr 2025 14:01:53 -0400 Subject: [PATCH] mm: page_alloc: speed up fallbacks in rmqueue_bulk() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The test robot identified c2f6ea38fc1b ("mm: page_alloc: don't steal single pages from biggest buddy") as the root cause of a 56.4% regression in vm-scalability::lru-file-mmap-read. Carlos reports an earlier patch, c0cd6f557b90 ("mm: page_alloc: fix freelist movement during block conversion"), as the root cause for a regression in worst-case zone->lock+irqoff hold times. Both of these patches modify the page allocator's fallback path to be less greedy in an effort to stave off fragmentation. The flip side of this is that fallbacks are also less productive each time around, which means the fallback search can run much more frequently. Carlos' traces point to rmqueue_bulk() specifically, which tries to refill the percpu cache by allocating a large batch of pages in a loop. It highlights how once the native freelists are exhausted, the fallback code first scans orders top-down for whole blocks to claim, then falls back to a bottom-up search for the smallest buddy to steal. For the next batch page, it goes through the same thing again. This can be made more efficient. Since rmqueue_bulk() holds the zone->lock over the entire batch, the freelists are not subject to outside changes; when the search for a block to claim has already failed, there is no point in trying again for the next page. Modify __rmqueue() to remember the last successful fallback mode, and restart directly from there on the next rmqueue_bulk() iteration. Oliver confirms that this improves beyond the regression that the test robot reported against c2f6ea38fc1b: commit: f3b92176f4 ("tools/selftests: add guard region test for /proc/$pid/pagemap") c2f6ea38fc ("mm: page_alloc: don't steal single pages from biggest buddy") acc4d5ff0b ("Merge tag 'net-6.15-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net") 2c847f27c3 ("mm: page_alloc: speed up fallbacks in rmqueue_bulk()") <--- your patch f3b92176f4f7100f c2f6ea38fc1b640aa7a2e155cc1 acc4d5ff0b61eb1715c498b6536 2c847f27c37da65a93d23c237c5 ---------------- --------------------------- --------------------------- --------------------------- %stddev %change %stddev %change %stddev %change %stddev \ | \ | \ | \ 25525364 ± 3% -56.4% 11135467 -57.8% 10779336 +31.6% 33581409 vm-scalability.throughput Carlos confirms that worst-case times are almost fully recovered compared to before the earlier culprit patch: 2dd482ba627d (before freelist hygiene): 1ms c0cd6f557b90 (after freelist hygiene): 90ms next-20250319 (steal smallest buddy): 280ms this patch : 8ms [jackmanb(a)google.com: comment updates] Link: https://lkml.kernel.org/r/D92AC0P9594X.3BML64MUKTF8Z@google.com [hannes(a)cmpxchg.org: reset rmqueue_mode in rmqueue_buddy() error loop, per Yunsheng Lin] Link: https://lkml.kernel.org/r/20250409140023.GA2313@cmpxchg.org Link: https://lkml.kernel.org/r/20250407180154.63348-1-hannes@cmpxchg.org Fixes: c0cd6f557b90 ("mm: page_alloc: fix freelist movement during block conversion") Fixes: c2f6ea38fc1b ("mm: page_alloc: don't steal single pages from biggest buddy") Signed-off-by: Johannes Weiner <hannes(a)cmpxchg.org> Signed-off-by: Brendan Jackman <jackmanb(a)google.com> Reported-by: kernel test robot <oliver.sang(a)intel.com> Reported-by: Carlos Song <carlos.song(a)nxp.com> Tested-by: Carlos Song <carlos.song(a)nxp.com> Tested-by: kernel test robot <oliver.sang(a)intel.com> Closes: https://lore.kernel.org/oe-lkp/202503271547.fc08b188-lkp@intel.com Reviewed-by: Brendan Jackman <jackmanb(a)google.com> Tested-by: Shivank Garg <shivankg(a)amd.com> Acked-by: Zi Yan <ziy(a)nvidia.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> [6.10+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 9a219fe8e130..1715e34b91af 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2183,23 +2183,15 @@ try_to_claim_block(struct zone *zone, struct page *page, } /* - * Try finding a free buddy page on the fallback list. - * - * This will attempt to claim a whole pageblock for the requested type - * to ensure grouping of such requests in the future. - * - * If a whole block cannot be claimed, steal an individual page, regressing to - * __rmqueue_smallest() logic to at least break up as little contiguity as - * possible. + * Try to allocate from some fallback migratetype by claiming the entire block, + * i.e. converting it to the allocation's start migratetype. * * The use of signed ints for order and current_order is a deliberate * deviation from the rest of this file, to make the for loop * condition simpler. - * - * Return the stolen page, or NULL if none can be found. */ static __always_inline struct page * -__rmqueue_fallback(struct zone *zone, int order, int start_migratetype, +__rmqueue_claim(struct zone *zone, int order, int start_migratetype, unsigned int alloc_flags) { struct free_area *area; @@ -2237,14 +2229,29 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype, page = try_to_claim_block(zone, page, current_order, order, start_migratetype, fallback_mt, alloc_flags); - if (page) - goto got_one; + if (page) { + trace_mm_page_alloc_extfrag(page, order, current_order, + start_migratetype, fallback_mt); + return page; + } } - if (alloc_flags & ALLOC_NOFRAGMENT) - return NULL; + return NULL; +} + +/* + * Try to steal a single page from some fallback migratetype. Leave the rest of + * the block as its current migratetype, potentially causing fragmentation. + */ +static __always_inline struct page * +__rmqueue_steal(struct zone *zone, int order, int start_migratetype) +{ + struct free_area *area; + int current_order; + struct page *page; + int fallback_mt; + bool claim_block; - /* No luck claiming pageblock. Find the smallest fallback page */ for (current_order = order; current_order < NR_PAGE_ORDERS; current_order++) { area = &(zone->free_area[current_order]); fallback_mt = find_suitable_fallback(area, current_order, @@ -2254,25 +2261,28 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype, page = get_page_from_free_area(area, fallback_mt); page_del_and_expand(zone, page, order, current_order, fallback_mt); - goto got_one; + trace_mm_page_alloc_extfrag(page, order, current_order, + start_migratetype, fallback_mt); + return page; } return NULL; - -got_one: - trace_mm_page_alloc_extfrag(page, order, current_order, - start_migratetype, fallback_mt); - - return page; } +enum rmqueue_mode { + RMQUEUE_NORMAL, + RMQUEUE_CMA, + RMQUEUE_CLAIM, + RMQUEUE_STEAL, +}; + /* * Do the hard work of removing an element from the buddy allocator. * Call me with the zone->lock already held. */ static __always_inline struct page * __rmqueue(struct zone *zone, unsigned int order, int migratetype, - unsigned int alloc_flags) + unsigned int alloc_flags, enum rmqueue_mode *mode) { struct page *page; @@ -2291,16 +2301,48 @@ __rmqueue(struct zone *zone, unsigned int order, int migratetype, } } - page = __rmqueue_smallest(zone, order, migratetype); - if (unlikely(!page)) { - if (alloc_flags & ALLOC_CMA) + /* + * First try the freelists of the requested migratetype, then try + * fallbacks modes with increasing levels of fragmentation risk. + * + * The fallback logic is expensive and rmqueue_bulk() calls in + * a loop with the zone->lock held, meaning the freelists are + * not subject to any outside changes. Remember in *mode where + * we found pay dirt, to save us the search on the next call. + */ + switch (*mode) { + case RMQUEUE_NORMAL: + page = __rmqueue_smallest(zone, order, migratetype); + if (page) + return page; + fallthrough; + case RMQUEUE_CMA: + if (alloc_flags & ALLOC_CMA) { page = __rmqueue_cma_fallback(zone, order); - - if (!page) - page = __rmqueue_fallback(zone, order, migratetype, - alloc_flags); + if (page) { + *mode = RMQUEUE_CMA; + return page; + } + } + fallthrough; + case RMQUEUE_CLAIM: + page = __rmqueue_claim(zone, order, migratetype, alloc_flags); + if (page) { + /* Replenished preferred freelist, back to normal mode. */ + *mode = RMQUEUE_NORMAL; + return page; + } + fallthrough; + case RMQUEUE_STEAL: + if (!(alloc_flags & ALLOC_NOFRAGMENT)) { + page = __rmqueue_steal(zone, order, migratetype); + if (page) { + *mode = RMQUEUE_STEAL; + return page; + } + } } - return page; + return NULL; } /* @@ -2312,6 +2354,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, unsigned long count, struct list_head *list, int migratetype, unsigned int alloc_flags) { + enum rmqueue_mode rmqm = RMQUEUE_NORMAL; unsigned long flags; int i; @@ -2323,7 +2366,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, } for (i = 0; i < count; ++i) { struct page *page = __rmqueue(zone, order, migratetype, - alloc_flags); + alloc_flags, &rmqm); if (unlikely(page == NULL)) break; @@ -2948,7 +2991,9 @@ struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone, if (alloc_flags & ALLOC_HIGHATOMIC) page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC); if (!page) { - page = __rmqueue(zone, order, migratetype, alloc_flags); + enum rmqueue_mode rmqm = RMQUEUE_NORMAL; + + page = __rmqueue(zone, order, migratetype, alloc_flags, &rmqm); /* * If the allocation fails, allow OOM handling and

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FAILED: patch "[PATCH] mm/compaction: fix bug in hugetlb handling pathway" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-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-5.15.y git checkout FETCH_HEAD git cherry-pick -x a84edd52f0a0fa193f0f685769939cf84510755b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042101-algorithm-simply-9ce6@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a84edd52f0a0fa193f0f685769939cf84510755b Mon Sep 17 00:00:00 2001 From: "Vishal Moola (Oracle)" <vishal.moola(a)gmail.com> Date: Mon, 31 Mar 2025 19:10:24 -0700 Subject: [PATCH] mm/compaction: fix bug in hugetlb handling pathway The compaction code doesn't take references on pages until we're certain we should attempt to handle it. In the hugetlb case, isolate_or_dissolve_huge_page() may return -EBUSY without taking a reference to the folio associated with our pfn. If our folio's refcount drops to 0, compound_nr() becomes unpredictable, making low_pfn and nr_scanned unreliable. The user-visible effect is minimal - this should rarely happen (if ever). Fix this by storing the folio statistics earlier on the stack (just like the THP and Buddy cases). Also revert commit 66fe1cf7f581 ("mm: compaction: use helper compound_nr in isolate_migratepages_block") to make backporting easier. Link: https://lkml.kernel.org/r/20250401021025.637333-1-vishal.moola@gmail.com Fixes: 369fa227c219 ("mm: make alloc_contig_range handle free hugetlb pages") Signed-off-by: Vishal Moola (Oracle) <vishal.moola(a)gmail.com> Acked-by: Oscar Salvador <osalvador(a)suse.de> Reviewed-by: Zi Yan <ziy(a)nvidia.com> Cc: Miaohe Lin <linmiaohe(a)huawei.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/compaction.c b/mm/compaction.c index 139f00c0308a..ca71fd3c3181 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -981,13 +981,13 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, } if (PageHuge(page)) { + const unsigned int order = compound_order(page); /* * skip hugetlbfs if we are not compacting for pages * bigger than its order. THPs and other compound pages * are handled below. */ if (!cc->alloc_contig) { - const unsigned int order = compound_order(page); if (order <= MAX_PAGE_ORDER) { low_pfn += (1UL << order) - 1; @@ -1011,8 +1011,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, /* Do not report -EBUSY down the chain */ if (ret == -EBUSY) ret = 0; - low_pfn += compound_nr(page) - 1; - nr_scanned += compound_nr(page) - 1; + low_pfn += (1UL << order) - 1; + nr_scanned += (1UL << order) - 1; goto isolate_fail; }

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FAILED: patch "[PATCH] mm/compaction: fix bug in hugetlb handling pathway" 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 a84edd52f0a0fa193f0f685769939cf84510755b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042100-cabbie-enzyme-2411@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a84edd52f0a0fa193f0f685769939cf84510755b Mon Sep 17 00:00:00 2001 From: "Vishal Moola (Oracle)" <vishal.moola(a)gmail.com> Date: Mon, 31 Mar 2025 19:10:24 -0700 Subject: [PATCH] mm/compaction: fix bug in hugetlb handling pathway The compaction code doesn't take references on pages until we're certain we should attempt to handle it. In the hugetlb case, isolate_or_dissolve_huge_page() may return -EBUSY without taking a reference to the folio associated with our pfn. If our folio's refcount drops to 0, compound_nr() becomes unpredictable, making low_pfn and nr_scanned unreliable. The user-visible effect is minimal - this should rarely happen (if ever). Fix this by storing the folio statistics earlier on the stack (just like the THP and Buddy cases). Also revert commit 66fe1cf7f581 ("mm: compaction: use helper compound_nr in isolate_migratepages_block") to make backporting easier. Link: https://lkml.kernel.org/r/20250401021025.637333-1-vishal.moola@gmail.com Fixes: 369fa227c219 ("mm: make alloc_contig_range handle free hugetlb pages") Signed-off-by: Vishal Moola (Oracle) <vishal.moola(a)gmail.com> Acked-by: Oscar Salvador <osalvador(a)suse.de> Reviewed-by: Zi Yan <ziy(a)nvidia.com> Cc: Miaohe Lin <linmiaohe(a)huawei.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/compaction.c b/mm/compaction.c index 139f00c0308a..ca71fd3c3181 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -981,13 +981,13 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, } if (PageHuge(page)) { + const unsigned int order = compound_order(page); /* * skip hugetlbfs if we are not compacting for pages * bigger than its order. THPs and other compound pages * are handled below. */ if (!cc->alloc_contig) { - const unsigned int order = compound_order(page); if (order <= MAX_PAGE_ORDER) { low_pfn += (1UL << order) - 1; @@ -1011,8 +1011,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, /* Do not report -EBUSY down the chain */ if (ret == -EBUSY) ret = 0; - low_pfn += compound_nr(page) - 1; - nr_scanned += compound_nr(page) - 1; + low_pfn += (1UL << order) - 1; + nr_scanned += (1UL << order) - 1; goto isolate_fail; }

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