August 2025 - Linux-stable-mirror

[REGRESSION] stable-rc/linux-5.15.y: (build) ‘host_initiated’ undeclared (first use in this function) in arch/x...

by KernelCI bot

Hello, New build issue found on stable-rc/linux-5.15.y: --- ‘host_initiated’ undeclared (first use in this function) in arch/x86/kvm/vmx/vmx.o (arch/x86/kvm/vmx/vmx.c) [logspec:kbuild,kbuild.compiler.error] --- - dashboard: https://d.kernelci.org/i/maestro:f3f2b1eabef22152c0bfbd86fe01d397c2c3478a - giturl: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git - commit HEAD: 62f5d931273c281f86db2d54bfa496b2a2b400cc Log excerpt: ===================================================== arch/x86/kvm/vmx/vmx.c:2022:14: error: ‘host_initiated’ undeclared (first use in this function) 2022 | (host_initiated || guest_cpu_cap_has(vcpu, X86_FEATURE_RTM))) | ^~~~~~~~~~~~~~ arch/x86/kvm/vmx/vmx.c:2022:14: note: each undeclared identifier is reported only once for each function it appears in arch/x86/kvm/vmx/vmx.c:2022:32: error: implicit declaration of function ‘guest_cpu_cap_has’; did you mean ‘guest_cpuid_has’? [-Werror=implicit-function-declaration] 2022 | (host_initiated || guest_cpu_cap_has(vcpu, X86_FEATURE_RTM))) | ^~~~~~~~~~~~~~~~~ | guest_cpuid_has CC fs/kernfs/dir.o CC mm/msync.o CC security/landlock/fs.o CC arch/x86/kernel/cpu/perfctr-watchdog.o CC block/blk-mq-cpumap.o CC kernel/time/timekeeping.o cc1: all warnings being treated as errors ===================================================== # Builds where the incident occurred: ## cros://chromeos-5.15/x86_64/chromeos-intel-pineview.flavour.config+lab-setup+x86-board+CONFIG_MODULE_COMPRESS=n+CONFIG_MODULE_COMPRESS_NONE=y on (x86_64): - compiler: gcc-12 - dashboard: https://d.kernelci.org/build/maestro:689b7814233e484a3f8f20f4 #kernelci issue maestro:f3f2b1eabef22152c0bfbd86fe01d397c2c3478a Reported-by: kernelci.org bot <bot(a)kernelci.org> -- This is an experimental report format. Please send feedback in! Talk to us at kernelci(a)lists.linux.dev Made with love by the KernelCI team - https://kernelci.org

4 months, 2 weeks

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FAILED: patch "[PATCH] smb: server: Fix extension string in" 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 8e7d178d06e8937454b6d2f2811fa6a15656a214 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081244-octagon-curve-7925@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8e7d178d06e8937454b6d2f2811fa6a15656a214 Mon Sep 17 00:00:00 2001 From: Thorsten Blum <thorsten.blum(a)linux.dev> Date: Wed, 6 Aug 2025 03:03:49 +0200 Subject: [PATCH] smb: server: Fix extension string in ksmbd_extract_shortname() In ksmbd_extract_shortname(), strscpy() is incorrectly called with the length of the source string (excluding the NUL terminator) rather than the size of the destination buffer. This results in "__" being copied to 'extension' rather than "___" (two underscores instead of three). Use the destination buffer size instead to ensure that the string "___" (three underscores) is copied correctly. Cc: stable(a)vger.kernel.org Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Signed-off-by: Thorsten Blum <thorsten.blum(a)linux.dev> Acked-by: Namjae Jeon <linkinjeon(a)kernel.org> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/server/smb_common.c b/fs/smb/server/smb_common.c index 425c756bcfb8..b23203a1c286 100644 --- a/fs/smb/server/smb_common.c +++ b/fs/smb/server/smb_common.c @@ -515,7 +515,7 @@ int ksmbd_extract_shortname(struct ksmbd_conn *conn, const char *longname, p = strrchr(longname, '.'); if (p == longname) { /*name starts with a dot*/ - strscpy(extension, "___", strlen("___")); + strscpy(extension, "___", sizeof(extension)); } else { if (p) { p++;

4 months, 2 weeks

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FAILED: patch "[PATCH] smb: server: Fix extension string in" failed to apply to 6.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.15-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-6.15.y git checkout FETCH_HEAD git cherry-pick -x 8e7d178d06e8937454b6d2f2811fa6a15656a214 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081241-bobsled-broiling-d341@gregkh' --subject-prefix 'PATCH 6.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8e7d178d06e8937454b6d2f2811fa6a15656a214 Mon Sep 17 00:00:00 2001 From: Thorsten Blum <thorsten.blum(a)linux.dev> Date: Wed, 6 Aug 2025 03:03:49 +0200 Subject: [PATCH] smb: server: Fix extension string in ksmbd_extract_shortname() In ksmbd_extract_shortname(), strscpy() is incorrectly called with the length of the source string (excluding the NUL terminator) rather than the size of the destination buffer. This results in "__" being copied to 'extension' rather than "___" (two underscores instead of three). Use the destination buffer size instead to ensure that the string "___" (three underscores) is copied correctly. Cc: stable(a)vger.kernel.org Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Signed-off-by: Thorsten Blum <thorsten.blum(a)linux.dev> Acked-by: Namjae Jeon <linkinjeon(a)kernel.org> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/server/smb_common.c b/fs/smb/server/smb_common.c index 425c756bcfb8..b23203a1c286 100644 --- a/fs/smb/server/smb_common.c +++ b/fs/smb/server/smb_common.c @@ -515,7 +515,7 @@ int ksmbd_extract_shortname(struct ksmbd_conn *conn, const char *longname, p = strrchr(longname, '.'); if (p == longname) { /*name starts with a dot*/ - strscpy(extension, "___", strlen("___")); + strscpy(extension, "___", sizeof(extension)); } else { if (p) { p++;

4 months, 2 weeks

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FAILED: patch "[PATCH] smb: server: Fix extension string in" failed to apply to 6.16-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.16-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-6.16.y git checkout FETCH_HEAD git cherry-pick -x 8e7d178d06e8937454b6d2f2811fa6a15656a214 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081238-unnamed-nappy-9be5@gregkh' --subject-prefix 'PATCH 6.16.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8e7d178d06e8937454b6d2f2811fa6a15656a214 Mon Sep 17 00:00:00 2001 From: Thorsten Blum <thorsten.blum(a)linux.dev> Date: Wed, 6 Aug 2025 03:03:49 +0200 Subject: [PATCH] smb: server: Fix extension string in ksmbd_extract_shortname() In ksmbd_extract_shortname(), strscpy() is incorrectly called with the length of the source string (excluding the NUL terminator) rather than the size of the destination buffer. This results in "__" being copied to 'extension' rather than "___" (two underscores instead of three). Use the destination buffer size instead to ensure that the string "___" (three underscores) is copied correctly. Cc: stable(a)vger.kernel.org Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Signed-off-by: Thorsten Blum <thorsten.blum(a)linux.dev> Acked-by: Namjae Jeon <linkinjeon(a)kernel.org> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/server/smb_common.c b/fs/smb/server/smb_common.c index 425c756bcfb8..b23203a1c286 100644 --- a/fs/smb/server/smb_common.c +++ b/fs/smb/server/smb_common.c @@ -515,7 +515,7 @@ int ksmbd_extract_shortname(struct ksmbd_conn *conn, const char *longname, p = strrchr(longname, '.'); if (p == longname) { /*name starts with a dot*/ - strscpy(extension, "___", strlen("___")); + strscpy(extension, "___", sizeof(extension)); } else { if (p) { p++;

4 months, 2 weeks

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FAILED: patch "[PATCH] smb: client: fix netns refcount leak after net_passive" 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 59b33fab4ca4d7dacc03367082777627e05d0323 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081245-premises-spoiler-440c@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 59b33fab4ca4d7dacc03367082777627e05d0323 Mon Sep 17 00:00:00 2001 From: Wang Zhaolong <wangzhaolong(a)huaweicloud.com> Date: Thu, 17 Jul 2025 21:29:26 +0800 Subject: [PATCH] smb: client: fix netns refcount leak after net_passive changes After commit 5c70eb5c593d ("net: better track kernel sockets lifetime"), kernel sockets now use net_passive reference counting. However, commit 95d2b9f693ff ("Revert "smb: client: fix TCP timers deadlock after rmmod"") restored the manual socket refcount manipulation without adapting to this new mechanism, causing a memory leak. The issue can be reproduced by[1]: 1. Creating a network namespace 2. Mounting and Unmounting CIFS within the namespace 3. Deleting the namespace Some memory leaks may appear after a period of time following step 3. unreferenced object 0xffff9951419f6b00 (size 256): comm "ip", pid 447, jiffies 4294692389 (age 14.730s) hex dump (first 32 bytes): 1b 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 80 77 c2 44 51 99 ff ff .........w.DQ... backtrace: __kmem_cache_alloc_node+0x30e/0x3d0 __kmalloc+0x52/0x120 net_alloc_generic+0x1d/0x30 copy_net_ns+0x86/0x200 create_new_namespaces+0x117/0x300 unshare_nsproxy_namespaces+0x60/0xa0 ksys_unshare+0x148/0x360 __x64_sys_unshare+0x12/0x20 do_syscall_64+0x59/0x110 entry_SYSCALL_64_after_hwframe+0x78/0xe2 ... unreferenced object 0xffff9951442e7500 (size 32): comm "mount.cifs", pid 475, jiffies 4294693782 (age 13.343s) hex dump (first 32 bytes): 40 c5 38 46 51 99 ff ff 18 01 96 42 51 99 ff ff @.8FQ......BQ... 01 00 00 00 6f 00 c5 07 6f 00 d8 07 00 00 00 00 ....o...o....... backtrace: __kmem_cache_alloc_node+0x30e/0x3d0 kmalloc_trace+0x2a/0x90 ref_tracker_alloc+0x8e/0x1d0 sk_alloc+0x18c/0x1c0 inet_create+0xf1/0x370 __sock_create+0xd7/0x1e0 generic_ip_connect+0x1d4/0x5a0 [cifs] cifs_get_tcp_session+0x5d0/0x8a0 [cifs] cifs_mount_get_session+0x47/0x1b0 [cifs] dfs_mount_share+0xfa/0xa10 [cifs] cifs_mount+0x68/0x2b0 [cifs] cifs_smb3_do_mount+0x10b/0x760 [cifs] smb3_get_tree+0x112/0x2e0 [cifs] vfs_get_tree+0x29/0xf0 path_mount+0x2d4/0xa00 __se_sys_mount+0x165/0x1d0 Root cause: When creating kernel sockets, sk_alloc() calls net_passive_inc() for sockets with sk_net_refcnt=0. The CIFS code manually converts kernel sockets to user sockets by setting sk_net_refcnt=1, but doesn't call the corresponding net_passive_dec(). This creates an imbalance in the net_passive counter, which prevents the network namespace from being destroyed when its last user reference is dropped. As a result, the entire namespace and all its associated resources remain allocated. Timeline of patches leading to this issue: - commit ef7134c7fc48 ("smb: client: Fix use-after-free of network namespace.") in v6.12 fixed the original netns UAF by manually managing socket refcounts - commit e9f2517a3e18 ("smb: client: fix TCP timers deadlock after rmmod") in v6.13 attempted to use kernel sockets but introduced TCP timer issues - commit 5c70eb5c593d ("net: better track kernel sockets lifetime") in v6.14-rc5 introduced the net_passive mechanism with sk_net_refcnt_upgrade() for proper socket conversion - commit 95d2b9f693ff ("Revert "smb: client: fix TCP timers deadlock after rmmod"") in v6.15-rc3 reverted to manual refcount management without adapting to the new net_passive changes Fix this by using sk_net_refcnt_upgrade() which properly handles the net_passive counter when converting kernel sockets to user sockets. Link: https://bugzilla.kernel.org/show_bug.cgi?id=220343 [1] Fixes: 95d2b9f693ff ("Revert "smb: client: fix TCP timers deadlock after rmmod"") Cc: stable(a)vger.kernel.org Reviewed-by: Kuniyuki Iwashima <kuniyu(a)google.com> Reviewed-by: Enzo Matsumiya <ematsumiya(a)suse.de> Signed-off-by: Wang Zhaolong <wangzhaolong(a)huaweicloud.com> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index 205f547ca49e..5eec8957f2a9 100644 --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -3362,18 +3362,15 @@ generic_ip_connect(struct TCP_Server_Info *server) struct net *net = cifs_net_ns(server); struct sock *sk; - rc = __sock_create(net, sfamily, SOCK_STREAM, - IPPROTO_TCP, &server->ssocket, 1); + rc = sock_create_kern(net, sfamily, SOCK_STREAM, + IPPROTO_TCP, &server->ssocket); if (rc < 0) { cifs_server_dbg(VFS, "Error %d creating socket\n", rc); return rc; } sk = server->ssocket->sk; - __netns_tracker_free(net, &sk->ns_tracker, false); - sk->sk_net_refcnt = 1; - get_net_track(net, &sk->ns_tracker, GFP_KERNEL); - sock_inuse_add(net, 1); + sk_net_refcnt_upgrade(sk); /* BB other socket options to set KEEPALIVE, NODELAY? */ cifs_dbg(FYI, "Socket created\n");

4 months, 2 weeks

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FAILED: patch "[PATCH] smb: client: fix netns refcount leak after net_passive" 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 59b33fab4ca4d7dacc03367082777627e05d0323 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081230-dentist-cautious-7bb4@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 59b33fab4ca4d7dacc03367082777627e05d0323 Mon Sep 17 00:00:00 2001 From: Wang Zhaolong <wangzhaolong(a)huaweicloud.com> Date: Thu, 17 Jul 2025 21:29:26 +0800 Subject: [PATCH] smb: client: fix netns refcount leak after net_passive changes After commit 5c70eb5c593d ("net: better track kernel sockets lifetime"), kernel sockets now use net_passive reference counting. However, commit 95d2b9f693ff ("Revert "smb: client: fix TCP timers deadlock after rmmod"") restored the manual socket refcount manipulation without adapting to this new mechanism, causing a memory leak. The issue can be reproduced by[1]: 1. Creating a network namespace 2. Mounting and Unmounting CIFS within the namespace 3. Deleting the namespace Some memory leaks may appear after a period of time following step 3. unreferenced object 0xffff9951419f6b00 (size 256): comm "ip", pid 447, jiffies 4294692389 (age 14.730s) hex dump (first 32 bytes): 1b 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 80 77 c2 44 51 99 ff ff .........w.DQ... backtrace: __kmem_cache_alloc_node+0x30e/0x3d0 __kmalloc+0x52/0x120 net_alloc_generic+0x1d/0x30 copy_net_ns+0x86/0x200 create_new_namespaces+0x117/0x300 unshare_nsproxy_namespaces+0x60/0xa0 ksys_unshare+0x148/0x360 __x64_sys_unshare+0x12/0x20 do_syscall_64+0x59/0x110 entry_SYSCALL_64_after_hwframe+0x78/0xe2 ... unreferenced object 0xffff9951442e7500 (size 32): comm "mount.cifs", pid 475, jiffies 4294693782 (age 13.343s) hex dump (first 32 bytes): 40 c5 38 46 51 99 ff ff 18 01 96 42 51 99 ff ff @.8FQ......BQ... 01 00 00 00 6f 00 c5 07 6f 00 d8 07 00 00 00 00 ....o...o....... backtrace: __kmem_cache_alloc_node+0x30e/0x3d0 kmalloc_trace+0x2a/0x90 ref_tracker_alloc+0x8e/0x1d0 sk_alloc+0x18c/0x1c0 inet_create+0xf1/0x370 __sock_create+0xd7/0x1e0 generic_ip_connect+0x1d4/0x5a0 [cifs] cifs_get_tcp_session+0x5d0/0x8a0 [cifs] cifs_mount_get_session+0x47/0x1b0 [cifs] dfs_mount_share+0xfa/0xa10 [cifs] cifs_mount+0x68/0x2b0 [cifs] cifs_smb3_do_mount+0x10b/0x760 [cifs] smb3_get_tree+0x112/0x2e0 [cifs] vfs_get_tree+0x29/0xf0 path_mount+0x2d4/0xa00 __se_sys_mount+0x165/0x1d0 Root cause: When creating kernel sockets, sk_alloc() calls net_passive_inc() for sockets with sk_net_refcnt=0. The CIFS code manually converts kernel sockets to user sockets by setting sk_net_refcnt=1, but doesn't call the corresponding net_passive_dec(). This creates an imbalance in the net_passive counter, which prevents the network namespace from being destroyed when its last user reference is dropped. As a result, the entire namespace and all its associated resources remain allocated. Timeline of patches leading to this issue: - commit ef7134c7fc48 ("smb: client: Fix use-after-free of network namespace.") in v6.12 fixed the original netns UAF by manually managing socket refcounts - commit e9f2517a3e18 ("smb: client: fix TCP timers deadlock after rmmod") in v6.13 attempted to use kernel sockets but introduced TCP timer issues - commit 5c70eb5c593d ("net: better track kernel sockets lifetime") in v6.14-rc5 introduced the net_passive mechanism with sk_net_refcnt_upgrade() for proper socket conversion - commit 95d2b9f693ff ("Revert "smb: client: fix TCP timers deadlock after rmmod"") in v6.15-rc3 reverted to manual refcount management without adapting to the new net_passive changes Fix this by using sk_net_refcnt_upgrade() which properly handles the net_passive counter when converting kernel sockets to user sockets. Link: https://bugzilla.kernel.org/show_bug.cgi?id=220343 [1] Fixes: 95d2b9f693ff ("Revert "smb: client: fix TCP timers deadlock after rmmod"") Cc: stable(a)vger.kernel.org Reviewed-by: Kuniyuki Iwashima <kuniyu(a)google.com> Reviewed-by: Enzo Matsumiya <ematsumiya(a)suse.de> Signed-off-by: Wang Zhaolong <wangzhaolong(a)huaweicloud.com> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index 205f547ca49e..5eec8957f2a9 100644 --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -3362,18 +3362,15 @@ generic_ip_connect(struct TCP_Server_Info *server) struct net *net = cifs_net_ns(server); struct sock *sk; - rc = __sock_create(net, sfamily, SOCK_STREAM, - IPPROTO_TCP, &server->ssocket, 1); + rc = sock_create_kern(net, sfamily, SOCK_STREAM, + IPPROTO_TCP, &server->ssocket); if (rc < 0) { cifs_server_dbg(VFS, "Error %d creating socket\n", rc); return rc; } sk = server->ssocket->sk; - __netns_tracker_free(net, &sk->ns_tracker, false); - sk->sk_net_refcnt = 1; - get_net_track(net, &sk->ns_tracker, GFP_KERNEL); - sock_inuse_add(net, 1); + sk_net_refcnt_upgrade(sk); /* BB other socket options to set KEEPALIVE, NODELAY? */ cifs_dbg(FYI, "Socket created\n");

4 months, 2 weeks

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FAILED: patch "[PATCH] mm: fix a UAF when vma->mm is freed after vma->vm_refcnt got" failed to apply to 6.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.15-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-6.15.y git checkout FETCH_HEAD git cherry-pick -x 9bbffee67ffd16360179327b57f3b1245579ef08 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081243-dense-paragraph-ed33@gregkh' --subject-prefix 'PATCH 6.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 9bbffee67ffd16360179327b57f3b1245579ef08 Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan <surenb(a)google.com> Date: Mon, 28 Jul 2025 10:53:55 -0700 Subject: [PATCH] mm: fix a UAF when vma->mm is freed after vma->vm_refcnt got dropped By inducing delays in the right places, Jann Horn created a reproducer for a hard to hit UAF issue that became possible after VMAs were allowed to be recycled by adding SLAB_TYPESAFE_BY_RCU to their cache. Race description is borrowed from Jann's discovery report: lock_vma_under_rcu() looks up a VMA locklessly with mas_walk() under rcu_read_lock(). At that point, the VMA may be concurrently freed, and it can be recycled by another process. vma_start_read() then increments the vma->vm_refcnt (if it is in an acceptable range), and if this succeeds, vma_start_read() can return a recycled VMA. In this scenario where the VMA has been recycled, lock_vma_under_rcu() will then detect the mismatching ->vm_mm pointer and drop the VMA through vma_end_read(), which calls vma_refcount_put(). vma_refcount_put() drops the refcount and then calls rcuwait_wake_up() using a copy of vma->vm_mm. This is wrong: It implicitly assumes that the caller is keeping the VMA's mm alive, but in this scenario the caller has no relation to the VMA's mm, so the rcuwait_wake_up() can cause UAF. The diagram depicting the race: T1 T2 T3 == == == lock_vma_under_rcu mas_walk <VMA gets removed from mm> mmap <the same VMA is reallocated> vma_start_read __refcount_inc_not_zero_limited_acquire munmap __vma_enter_locked refcount_add_not_zero vma_end_read vma_refcount_put __refcount_dec_and_test rcuwait_wait_event <finish operation> rcuwait_wake_up [UAF] Note that rcuwait_wait_event() in T3 does not block because refcount was already dropped by T1. At this point T3 can exit and free the mm causing UAF in T1. To avoid this we move vma->vm_mm verification into vma_start_read() and grab vma->vm_mm to stabilize it before vma_refcount_put() operation. [surenb(a)google.com: v3] Link: https://lkml.kernel.org/r/20250729145709.2731370-1-surenb@google.com Link: https://lkml.kernel.org/r/20250728175355.2282375-1-surenb@google.com Fixes: 3104138517fc ("mm: make vma cache SLAB_TYPESAFE_BY_RCU") Signed-off-by: Suren Baghdasaryan <surenb(a)google.com> Reported-by: Jann Horn <jannh(a)google.com> Closes: https://lore.kernel.org/all/CAG48ez0-deFbVH=E3jbkWx=X3uVbd8nWeo6kbJPQ0KoUD+… Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Acked-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Jann Horn <jannh(a)google.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h index 1f4f44951abe..11a078de9150 100644 --- a/include/linux/mmap_lock.h +++ b/include/linux/mmap_lock.h @@ -12,6 +12,7 @@ extern int rcuwait_wake_up(struct rcuwait *w); #include <linux/tracepoint-defs.h> #include <linux/types.h> #include <linux/cleanup.h> +#include <linux/sched/mm.h> #define MMAP_LOCK_INITIALIZER(name) \ .mmap_lock = __RWSEM_INITIALIZER((name).mmap_lock), @@ -154,6 +155,10 @@ static inline void vma_refcount_put(struct vm_area_struct *vma) * reused and attached to a different mm before we lock it. * Returns the vma on success, NULL on failure to lock and EAGAIN if vma got * detached. + * + * WARNING! The vma passed to this function cannot be used if the function + * fails to lock it because in certain cases RCU lock is dropped and then + * reacquired. Once RCU lock is dropped the vma can be concurently freed. */ static inline struct vm_area_struct *vma_start_read(struct mm_struct *mm, struct vm_area_struct *vma) @@ -183,6 +188,31 @@ static inline struct vm_area_struct *vma_start_read(struct mm_struct *mm, } rwsem_acquire_read(&vma->vmlock_dep_map, 0, 1, _RET_IP_); + + /* + * If vma got attached to another mm from under us, that mm is not + * stable and can be freed in the narrow window after vma->vm_refcnt + * is dropped and before rcuwait_wake_up(mm) is called. Grab it before + * releasing vma->vm_refcnt. + */ + if (unlikely(vma->vm_mm != mm)) { + /* Use a copy of vm_mm in case vma is freed after we drop vm_refcnt */ + struct mm_struct *other_mm = vma->vm_mm; + + /* + * __mmdrop() is a heavy operation and we don't need RCU + * protection here. Release RCU lock during these operations. + * We reinstate the RCU read lock as the caller expects it to + * be held when this function returns even on error. + */ + rcu_read_unlock(); + mmgrab(other_mm); + vma_refcount_put(vma); + mmdrop(other_mm); + rcu_read_lock(); + return NULL; + } + /* * Overflow of vm_lock_seq/mm_lock_seq might produce false locked result. * False unlocked result is impossible because we modify and check diff --git a/mm/mmap_lock.c b/mm/mmap_lock.c index 729fb7d0dd59..b006cec8e6fe 100644 --- a/mm/mmap_lock.c +++ b/mm/mmap_lock.c @@ -164,8 +164,7 @@ struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm, */ /* Check if the vma we locked is the right one. */ - if (unlikely(vma->vm_mm != mm || - address < vma->vm_start || address >= vma->vm_end)) + if (unlikely(address < vma->vm_start || address >= vma->vm_end)) goto inval_end_read; rcu_read_unlock(); @@ -236,11 +235,8 @@ struct vm_area_struct *lock_next_vma(struct mm_struct *mm, goto fallback; } - /* - * Verify the vma we locked belongs to the same address space and it's - * not behind of the last search position. - */ - if (unlikely(vma->vm_mm != mm || from_addr >= vma->vm_end)) + /* Verify the vma is not behind the last search position. */ + if (unlikely(from_addr >= vma->vm_end)) goto fallback_unlock; /*

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FAILED: patch "[PATCH] KVM: VMX: Allow guest to set DEBUGCTL.RTM_DEBUG if RTM is" 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 17ec2f965344ee3fd6620bef7ef68792f4ac3af0 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081208-scrubber-veggie-e1a5@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 17ec2f965344ee3fd6620bef7ef68792f4ac3af0 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Tue, 10 Jun 2025 16:20:06 -0700 Subject: [PATCH] KVM: VMX: Allow guest to set DEBUGCTL.RTM_DEBUG if RTM is supported Let the guest set DEBUGCTL.RTM_DEBUG if RTM is supported according to the guest CPUID model, as debug support is supposed to be available if RTM is supported, and there are no known downsides to letting the guest debug RTM aborts. Note, there are no known bug reports related to RTM_DEBUG, the primary motivation is to reduce the probability of breaking existing guests when a future change adds a missing consistency check on vmcs12.GUEST_DEBUGCTL (KVM currently lets L2 run with whatever hardware supports; whoops). Note #2, KVM already emulates DR6.RTM, and doesn't restrict access to DR7.RTM. Fixes: 83c529151ab0 ("KVM: x86: expose Intel cpu new features (HLE, RTM) to guest") Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20250610232010.162191-5-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc(a)google.com> diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index b7dded3c8113..fa878b136eba 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -419,6 +419,7 @@ #define DEBUGCTLMSR_FREEZE_PERFMON_ON_PMI (1UL << 12) #define DEBUGCTLMSR_FREEZE_IN_SMM_BIT 14 #define DEBUGCTLMSR_FREEZE_IN_SMM (1UL << DEBUGCTLMSR_FREEZE_IN_SMM_BIT) +#define DEBUGCTLMSR_RTM_DEBUG BIT(15) #define MSR_PEBS_FRONTEND 0x000003f7 diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 4ee6cc796855..311f6fa53b67 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2186,6 +2186,10 @@ static u64 vmx_get_supported_debugctl(struct kvm_vcpu *vcpu, bool host_initiated (host_initiated || intel_pmu_lbr_is_enabled(vcpu))) debugctl |= DEBUGCTLMSR_LBR | DEBUGCTLMSR_FREEZE_LBRS_ON_PMI; + if (boot_cpu_has(X86_FEATURE_RTM) && + (host_initiated || guest_cpu_cap_has(vcpu, X86_FEATURE_RTM))) + debugctl |= DEBUGCTLMSR_RTM_DEBUG; + return debugctl; }

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FAILED: patch "[PATCH] mm: fix a UAF when vma->mm is freed after vma->vm_refcnt got" failed to apply to 6.16-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.16-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-6.16.y git checkout FETCH_HEAD git cherry-pick -x 9bbffee67ffd16360179327b57f3b1245579ef08 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081237-buffed-scuba-d3f3@gregkh' --subject-prefix 'PATCH 6.16.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 9bbffee67ffd16360179327b57f3b1245579ef08 Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan <surenb(a)google.com> Date: Mon, 28 Jul 2025 10:53:55 -0700 Subject: [PATCH] mm: fix a UAF when vma->mm is freed after vma->vm_refcnt got dropped By inducing delays in the right places, Jann Horn created a reproducer for a hard to hit UAF issue that became possible after VMAs were allowed to be recycled by adding SLAB_TYPESAFE_BY_RCU to their cache. Race description is borrowed from Jann's discovery report: lock_vma_under_rcu() looks up a VMA locklessly with mas_walk() under rcu_read_lock(). At that point, the VMA may be concurrently freed, and it can be recycled by another process. vma_start_read() then increments the vma->vm_refcnt (if it is in an acceptable range), and if this succeeds, vma_start_read() can return a recycled VMA. In this scenario where the VMA has been recycled, lock_vma_under_rcu() will then detect the mismatching ->vm_mm pointer and drop the VMA through vma_end_read(), which calls vma_refcount_put(). vma_refcount_put() drops the refcount and then calls rcuwait_wake_up() using a copy of vma->vm_mm. This is wrong: It implicitly assumes that the caller is keeping the VMA's mm alive, but in this scenario the caller has no relation to the VMA's mm, so the rcuwait_wake_up() can cause UAF. The diagram depicting the race: T1 T2 T3 == == == lock_vma_under_rcu mas_walk <VMA gets removed from mm> mmap <the same VMA is reallocated> vma_start_read __refcount_inc_not_zero_limited_acquire munmap __vma_enter_locked refcount_add_not_zero vma_end_read vma_refcount_put __refcount_dec_and_test rcuwait_wait_event <finish operation> rcuwait_wake_up [UAF] Note that rcuwait_wait_event() in T3 does not block because refcount was already dropped by T1. At this point T3 can exit and free the mm causing UAF in T1. To avoid this we move vma->vm_mm verification into vma_start_read() and grab vma->vm_mm to stabilize it before vma_refcount_put() operation. [surenb(a)google.com: v3] Link: https://lkml.kernel.org/r/20250729145709.2731370-1-surenb@google.com Link: https://lkml.kernel.org/r/20250728175355.2282375-1-surenb@google.com Fixes: 3104138517fc ("mm: make vma cache SLAB_TYPESAFE_BY_RCU") Signed-off-by: Suren Baghdasaryan <surenb(a)google.com> Reported-by: Jann Horn <jannh(a)google.com> Closes: https://lore.kernel.org/all/CAG48ez0-deFbVH=E3jbkWx=X3uVbd8nWeo6kbJPQ0KoUD+… Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Acked-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Jann Horn <jannh(a)google.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h index 1f4f44951abe..11a078de9150 100644 --- a/include/linux/mmap_lock.h +++ b/include/linux/mmap_lock.h @@ -12,6 +12,7 @@ extern int rcuwait_wake_up(struct rcuwait *w); #include <linux/tracepoint-defs.h> #include <linux/types.h> #include <linux/cleanup.h> +#include <linux/sched/mm.h> #define MMAP_LOCK_INITIALIZER(name) \ .mmap_lock = __RWSEM_INITIALIZER((name).mmap_lock), @@ -154,6 +155,10 @@ static inline void vma_refcount_put(struct vm_area_struct *vma) * reused and attached to a different mm before we lock it. * Returns the vma on success, NULL on failure to lock and EAGAIN if vma got * detached. + * + * WARNING! The vma passed to this function cannot be used if the function + * fails to lock it because in certain cases RCU lock is dropped and then + * reacquired. Once RCU lock is dropped the vma can be concurently freed. */ static inline struct vm_area_struct *vma_start_read(struct mm_struct *mm, struct vm_area_struct *vma) @@ -183,6 +188,31 @@ static inline struct vm_area_struct *vma_start_read(struct mm_struct *mm, } rwsem_acquire_read(&vma->vmlock_dep_map, 0, 1, _RET_IP_); + + /* + * If vma got attached to another mm from under us, that mm is not + * stable and can be freed in the narrow window after vma->vm_refcnt + * is dropped and before rcuwait_wake_up(mm) is called. Grab it before + * releasing vma->vm_refcnt. + */ + if (unlikely(vma->vm_mm != mm)) { + /* Use a copy of vm_mm in case vma is freed after we drop vm_refcnt */ + struct mm_struct *other_mm = vma->vm_mm; + + /* + * __mmdrop() is a heavy operation and we don't need RCU + * protection here. Release RCU lock during these operations. + * We reinstate the RCU read lock as the caller expects it to + * be held when this function returns even on error. + */ + rcu_read_unlock(); + mmgrab(other_mm); + vma_refcount_put(vma); + mmdrop(other_mm); + rcu_read_lock(); + return NULL; + } + /* * Overflow of vm_lock_seq/mm_lock_seq might produce false locked result. * False unlocked result is impossible because we modify and check diff --git a/mm/mmap_lock.c b/mm/mmap_lock.c index 729fb7d0dd59..b006cec8e6fe 100644 --- a/mm/mmap_lock.c +++ b/mm/mmap_lock.c @@ -164,8 +164,7 @@ struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm, */ /* Check if the vma we locked is the right one. */ - if (unlikely(vma->vm_mm != mm || - address < vma->vm_start || address >= vma->vm_end)) + if (unlikely(address < vma->vm_start || address >= vma->vm_end)) goto inval_end_read; rcu_read_unlock(); @@ -236,11 +235,8 @@ struct vm_area_struct *lock_next_vma(struct mm_struct *mm, goto fallback; } - /* - * Verify the vma we locked belongs to the same address space and it's - * not behind of the last search position. - */ - if (unlikely(vma->vm_mm != mm || from_addr >= vma->vm_end)) + /* Verify the vma is not behind the last search position. */ + if (unlikely(from_addr >= vma->vm_end)) goto fallback_unlock; /*

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[PATCH V4 mm-hotfixes 3/3] x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings()

by Harry Yoo

Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure page tables are properly synchronized when calling p*d_populate_kernel(). It is inteneded to synchronize page tables via pgd_pouplate_kernel() when 5-level paging is in use and via p4d_pouplate_kernel() when 4-level paging is used. This fixes intermittent boot failures on systems using 4-level paging and a large amount of persistent memory: BUG: unable to handle page fault for address: ffffe70000000034 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI RIP: 0010:__init_single_page+0x9/0x6d Call Trace: <TASK> __init_zone_device_page+0x17/0x5d memmap_init_zone_device+0x154/0x1bb pagemap_range+0x2e0/0x40f memremap_pages+0x10b/0x2f0 devm_memremap_pages+0x1e/0x60 dev_dax_probe+0xce/0x2ec [device_dax] dax_bus_probe+0x6d/0xc9 [... snip ...] </TASK> It also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap before sync_global_pgds() [1]: BUG: unable to handle page fault for address: ffffeb3ff1200000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI Tainted: [W]=WARN RIP: 0010:vmemmap_set_pmd+0xff/0x230 <TASK> vmemmap_populate_hugepages+0x176/0x180 vmemmap_populate+0x34/0x80 __populate_section_memmap+0x41/0x90 sparse_add_section+0x121/0x3e0 __add_pages+0xba/0x150 add_pages+0x1d/0x70 memremap_pages+0x3dc/0x810 devm_memremap_pages+0x1c/0x60 xe_devm_add+0x8b/0x100 [xe] xe_tile_init_noalloc+0x6a/0x70 [xe] xe_device_probe+0x48c/0x740 [xe] [... snip ...] Cc: <stable(a)vger.kernel.org> Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges") Closes: https://lore.kernel.org/linux-mm/20250311114420.240341-1-gwan-gyeong.mun@in… [1] Suggested-by: Dave Hansen <dave.hansen(a)linux.intel.com> Signed-off-by: Harry Yoo <harry.yoo(a)oracle.com> --- arch/x86/include/asm/pgtable_64_types.h | 3 +++ arch/x86/mm/init_64.c | 5 +++++ 2 files changed, 8 insertions(+) diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h index 4604f924d8b8..7eb61ef6a185 100644 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -36,6 +36,9 @@ static inline bool pgtable_l5_enabled(void) #define pgtable_l5_enabled() cpu_feature_enabled(X86_FEATURE_LA57) #endif /* USE_EARLY_PGTABLE_L5 */ +#define ARCH_PAGE_TABLE_SYNC_MASK \ + (pgtable_l5_enabled() ? PGTBL_PGD_MODIFIED : PGTBL_P4D_MODIFIED) + extern unsigned int pgdir_shift; extern unsigned int ptrs_per_p4d; diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 76e33bd7c556..a78b498c0dc3 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -223,6 +223,11 @@ static void sync_global_pgds(unsigned long start, unsigned long end) sync_global_pgds_l4(start, end); } +void arch_sync_kernel_mappings(unsigned long start, unsigned long end) +{ + sync_global_pgds(start, end); +} + /* * NOTE: This function is marked __ref because it calls __init function * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0. -- 2.43.0

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