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[PATCH 2/4] sunrpc: fix client side handling of tls alerts

by Olga Kornievskaia

A security exploit was discovered in NFS over TLS in tls_alert_recv due to its assumption that there is valid data in the msghdr's iterator's kvec. Instead, this patch proposes the rework how control messages are setup and used by sock_recvmsg(). If no control message structure is setup, kTLS layer will read and process TLS data record types. As soon as it encounters a TLS control message, it would return an error. At that point, NFS can setup a kvec backed control buffer and read in the control message such as a TLS alert. Msg iterator can advance the kvec pointer as a part of the copy process thus we need to revert the iterator before calling into the tls_alert_recv. Fixes: dea034b963c8 ("SUNRPC: Capture CMSG metadata on client-side receive") Suggested-by: Trond Myklebust <trondmy(a)hammerspace.com> Cc: <Stable(a)vger.kernel.org> Signed-off-by: Olga Kornievskaia <okorniev(a)redhat.com> --- net/sunrpc/xprtsock.c | 40 ++++++++++++++++++++++++++++++---------- 1 file changed, 30 insertions(+), 10 deletions(-) diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 04ff66758fc3..c5f7bbf5775f 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -358,7 +358,7 @@ xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp) static int xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg, - struct cmsghdr *cmsg, int ret) + unsigned int *msg_flags, struct cmsghdr *cmsg, int ret) { u8 content_type = tls_get_record_type(sock->sk, cmsg); u8 level, description; @@ -371,7 +371,7 @@ xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg, * record, even though there might be more frames * waiting to be decrypted. */ - msg->msg_flags &= ~MSG_EOR; + *msg_flags &= ~MSG_EOR; break; case TLS_RECORD_TYPE_ALERT: tls_alert_recv(sock->sk, msg, &level, &description); @@ -386,19 +386,33 @@ xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg, } static int -xs_sock_recv_cmsg(struct socket *sock, struct msghdr *msg, int flags) +xs_sock_recv_cmsg(struct socket *sock, unsigned int *msg_flags, int flags) { union { struct cmsghdr cmsg; u8 buf[CMSG_SPACE(sizeof(u8))]; } u; + u8 alert[2]; + struct kvec alert_kvec = { + .iov_base = alert, + .iov_len = sizeof(alert), + }; + struct msghdr msg = { + .msg_flags = *msg_flags, + .msg_control = &u, + .msg_controllen = sizeof(u), + }; int ret; - msg->msg_control = &u; - msg->msg_controllen = sizeof(u); - ret = sock_recvmsg(sock, msg, flags); - if (msg->msg_controllen != sizeof(u)) - ret = xs_sock_process_cmsg(sock, msg, &u.cmsg, ret); + iov_iter_kvec(&msg.msg_iter, ITER_DEST, &alert_kvec, 1, + alert_kvec.iov_len); + ret = sock_recvmsg(sock, &msg, flags); + if (ret > 0 && + tls_get_record_type(sock->sk, &u.cmsg) == TLS_RECORD_TYPE_ALERT) { + iov_iter_revert(&msg.msg_iter, ret); + ret = xs_sock_process_cmsg(sock, &msg, msg_flags, &u.cmsg, + -EAGAIN); + } return ret; } @@ -408,7 +422,13 @@ xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek) ssize_t ret; if (seek != 0) iov_iter_advance(&msg->msg_iter, seek); - ret = xs_sock_recv_cmsg(sock, msg, flags); + ret = sock_recvmsg(sock, msg, flags); + /* Handle TLS inband control message lazily */ + if (msg->msg_flags & MSG_CTRUNC) { + msg->msg_flags &= ~(MSG_CTRUNC | MSG_EOR); + if (ret == 0 || ret == -EIO) + ret = xs_sock_recv_cmsg(sock, &msg->msg_flags, flags); + } return ret > 0 ? ret + seek : ret; } @@ -434,7 +454,7 @@ xs_read_discard(struct socket *sock, struct msghdr *msg, int flags, size_t count) { iov_iter_discard(&msg->msg_iter, ITER_DEST, count); - return xs_sock_recv_cmsg(sock, msg, flags); + return xs_sock_recvmsg(sock, msg, flags, 0); } #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE -- 2.47.1

3 months, 1 week

1
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[PATCH 1/4] sunrpc: fix handling of server side tls alerts

by Olga Kornievskaia

Scott Mayhew discovered a security exploit in NFS over TLS in tls_alert_recv() due to its assumption it can read data from the msg iterator's kvec.. kTLS implementation splits TLS non-data record payload between the control message buffer (which includes the type such as TLS aler or TLS cipher change) and the rest of the payload (say TLS alert's level/description) which goes into the msg payload buffer. This patch proposes to rework how control messages are setup and used by sock_recvmsg(). If no control message structure is setup, kTLS layer will read and process TLS data record types. As soon as it encounters a TLS control message, it would return an error. At that point, NFS can setup a kvec backed msg buffer and read in the control message such as a TLS alert. Msg iterator can advance the kvec pointer as a part of the copy process thus we need to revert the iterator before calling into the tls_alert_recv. Reported-by: Scott Mayhew <smayhew(a)redhat.com> Fixes: 5e052dda121e ("SUNRPC: Recognize control messages in server-side TCP socket code") Suggested-by: Trond Myklebust <trondmy(a)hammerspace.com> Cc: <Stable(a)vger.kernel.org> Signed-off-by: Olga Kornievskaia <okorniev(a)redhat.com> --- net/sunrpc/svcsock.c | 43 +++++++++++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 8 deletions(-) diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 46c156b121db..e2c5e0e626f9 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -257,20 +257,47 @@ svc_tcp_sock_process_cmsg(struct socket *sock, struct msghdr *msg, } static int -svc_tcp_sock_recv_cmsg(struct svc_sock *svsk, struct msghdr *msg) +svc_tcp_sock_recv_cmsg(struct socket *sock, unsigned int *msg_flags) { union { struct cmsghdr cmsg; u8 buf[CMSG_SPACE(sizeof(u8))]; } u; - struct socket *sock = svsk->sk_sock; + u8 alert[2]; + struct kvec alert_kvec = { + .iov_base = alert, + .iov_len = sizeof(alert), + }; + struct msghdr msg = { + .msg_flags = *msg_flags, + .msg_control = &u, + .msg_controllen = sizeof(u), + }; + int ret; + + iov_iter_kvec(&msg.msg_iter, ITER_DEST, &alert_kvec, 1, + alert_kvec.iov_len); + ret = sock_recvmsg(sock, &msg, MSG_DONTWAIT); + if (ret > 0 && + tls_get_record_type(sock->sk, &u.cmsg) == TLS_RECORD_TYPE_ALERT) { + iov_iter_revert(&msg.msg_iter, ret); + ret = svc_tcp_sock_process_cmsg(sock, &msg, &u.cmsg, -EAGAIN); + } + return ret; +} + +static int +svc_tcp_sock_recvmsg(struct svc_sock *svsk, struct msghdr *msg) +{ int ret; + struct socket *sock = svsk->sk_sock; - msg->msg_control = &u; - msg->msg_controllen = sizeof(u); ret = sock_recvmsg(sock, msg, MSG_DONTWAIT); - if (unlikely(msg->msg_controllen != sizeof(u))) - ret = svc_tcp_sock_process_cmsg(sock, msg, &u.cmsg, ret); + if (msg->msg_flags & MSG_CTRUNC) { + msg->msg_flags &= ~(MSG_CTRUNC | MSG_EOR); + if (ret == 0 || ret == -EIO) + ret = svc_tcp_sock_recv_cmsg(sock, &msg->msg_flags); + } return ret; } @@ -321,7 +348,7 @@ static ssize_t svc_tcp_read_msg(struct svc_rqst *rqstp, size_t buflen, iov_iter_advance(&msg.msg_iter, seek); buflen -= seek; } - len = svc_tcp_sock_recv_cmsg(svsk, &msg); + len = svc_tcp_sock_recvmsg(svsk, &msg); if (len > 0) svc_flush_bvec(bvec, len, seek); @@ -1018,7 +1045,7 @@ static ssize_t svc_tcp_read_marker(struct svc_sock *svsk, iov.iov_base = ((char *)&svsk->sk_marker) + svsk->sk_tcplen; iov.iov_len = want; iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, want); - len = svc_tcp_sock_recv_cmsg(svsk, &msg); + len = svc_tcp_sock_recvmsg(svsk, &msg); if (len < 0) return len; svsk->sk_tcplen += len; -- 2.47.1

3 months, 1 week

1
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FAILED: patch "[PATCH] drm/sched: Remove optimization that causes hang when killing" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-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-5.10.y git checkout FETCH_HEAD git cherry-pick -x 15f77764e90a713ee3916ca424757688e4f565b9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025072854-humbling-collector-aca6@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 15f77764e90a713ee3916ca424757688e4f565b9 Mon Sep 17 00:00:00 2001 From: "Lin.Cao" <lincao12(a)amd.com> Date: Thu, 17 Jul 2025 16:44:53 +0800 Subject: [PATCH] drm/sched: Remove optimization that causes hang when killing dependent jobs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When application A submits jobs and application B submits a job with a dependency on A's fence, the normal flow wakes up the scheduler after processing each job. However, the optimization in drm_sched_entity_add_dependency_cb() uses a callback that only clears dependencies without waking up the scheduler. When application A is killed before its jobs can run, the callback gets triggered but only clears the dependency without waking up the scheduler, causing the scheduler to enter sleep state and application B to hang. Remove the optimization by deleting drm_sched_entity_clear_dep() and its usage, ensuring the scheduler is always woken up when dependencies are cleared. Fixes: 777dbd458c89 ("drm/amdgpu: drop a dummy wakeup scheduler") Cc: stable(a)vger.kernel.org # v4.6+ Signed-off-by: Lin.Cao <lincao12(a)amd.com> Reviewed-by: Christian König <christian.koenig(a)amd.com> Signed-off-by: Philipp Stanner <phasta(a)kernel.org> Link: https://lore.kernel.org/r/20250717084453.921097-1-lincao12@amd.com diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index e671aa241720..ac678de7fe5e 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -355,17 +355,6 @@ void drm_sched_entity_destroy(struct drm_sched_entity *entity) } EXPORT_SYMBOL(drm_sched_entity_destroy); -/* drm_sched_entity_clear_dep - callback to clear the entities dependency */ -static void drm_sched_entity_clear_dep(struct dma_fence *f, - struct dma_fence_cb *cb) -{ - struct drm_sched_entity *entity = - container_of(cb, struct drm_sched_entity, cb); - - entity->dependency = NULL; - dma_fence_put(f); -} - /* * drm_sched_entity_wakeup - callback to clear the entity's dependency and * wake up the scheduler @@ -376,7 +365,8 @@ static void drm_sched_entity_wakeup(struct dma_fence *f, struct drm_sched_entity *entity = container_of(cb, struct drm_sched_entity, cb); - drm_sched_entity_clear_dep(f, cb); + entity->dependency = NULL; + dma_fence_put(f); drm_sched_wakeup(entity->rq->sched); } @@ -429,13 +419,6 @@ static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity) fence = dma_fence_get(&s_fence->scheduled); dma_fence_put(entity->dependency); entity->dependency = fence; - if (!dma_fence_add_callback(fence, &entity->cb, - drm_sched_entity_clear_dep)) - return true; - - /* Ignore it when it is already scheduled */ - dma_fence_put(fence); - return false; } if (!dma_fence_add_callback(entity->dependency, &entity->cb,

3 months, 1 week

2
1
0 0

[PATCH 2/4] sunrpc: fix client side handling of tls alerts

by Olga Kornievskaia

A security exploit was discovered in NFS over TLS in tls_alert_recv due to its assumption that there is valid data in the msghdr's iterator's kvec. Instead, this patch proposes the rework how control messages are setup and used by sock_recvmsg(). If no control message structure is setup, kTLS layer will read and process TLS data record types. As soon as it encounters a TLS control message, it would return an error. At that point, NFS can setup a kvec backed control buffer and read in the control message such as a TLS alert. Msg iterator can advance the kvec pointer as a part of the copy process thus we need to revert the iterator before calling into the tls_alert_recv. Fixes: dea034b963c8 ("SUNRPC: Capture CMSG metadata on client-side receive") Suggested-by: Trond Myklebust <trondmy(a)hammerspace.com> Cc: <Stable(a)vger.kernel.org> Signed-off-by: Olga Kornievskaia <okorniev(a)redhat.com> --- net/sunrpc/xprtsock.c | 40 ++++++++++++++++++++++++++++++---------- 1 file changed, 30 insertions(+), 10 deletions(-) diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 04ff66758fc3..c5f7bbf5775f 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -358,7 +358,7 @@ xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp) static int xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg, - struct cmsghdr *cmsg, int ret) + unsigned int *msg_flags, struct cmsghdr *cmsg, int ret) { u8 content_type = tls_get_record_type(sock->sk, cmsg); u8 level, description; @@ -371,7 +371,7 @@ xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg, * record, even though there might be more frames * waiting to be decrypted. */ - msg->msg_flags &= ~MSG_EOR; + *msg_flags &= ~MSG_EOR; break; case TLS_RECORD_TYPE_ALERT: tls_alert_recv(sock->sk, msg, &level, &description); @@ -386,19 +386,33 @@ xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg, } static int -xs_sock_recv_cmsg(struct socket *sock, struct msghdr *msg, int flags) +xs_sock_recv_cmsg(struct socket *sock, unsigned int *msg_flags, int flags) { union { struct cmsghdr cmsg; u8 buf[CMSG_SPACE(sizeof(u8))]; } u; + u8 alert[2]; + struct kvec alert_kvec = { + .iov_base = alert, + .iov_len = sizeof(alert), + }; + struct msghdr msg = { + .msg_flags = *msg_flags, + .msg_control = &u, + .msg_controllen = sizeof(u), + }; int ret; - msg->msg_control = &u; - msg->msg_controllen = sizeof(u); - ret = sock_recvmsg(sock, msg, flags); - if (msg->msg_controllen != sizeof(u)) - ret = xs_sock_process_cmsg(sock, msg, &u.cmsg, ret); + iov_iter_kvec(&msg.msg_iter, ITER_DEST, &alert_kvec, 1, + alert_kvec.iov_len); + ret = sock_recvmsg(sock, &msg, flags); + if (ret > 0 && + tls_get_record_type(sock->sk, &u.cmsg) == TLS_RECORD_TYPE_ALERT) { + iov_iter_revert(&msg.msg_iter, ret); + ret = xs_sock_process_cmsg(sock, &msg, msg_flags, &u.cmsg, + -EAGAIN); + } return ret; } @@ -408,7 +422,13 @@ xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek) ssize_t ret; if (seek != 0) iov_iter_advance(&msg->msg_iter, seek); - ret = xs_sock_recv_cmsg(sock, msg, flags); + ret = sock_recvmsg(sock, msg, flags); + /* Handle TLS inband control message lazily */ + if (msg->msg_flags & MSG_CTRUNC) { + msg->msg_flags &= ~(MSG_CTRUNC | MSG_EOR); + if (ret == 0 || ret == -EIO) + ret = xs_sock_recv_cmsg(sock, &msg->msg_flags, flags); + } return ret > 0 ? ret + seek : ret; } @@ -434,7 +454,7 @@ xs_read_discard(struct socket *sock, struct msghdr *msg, int flags, size_t count) { iov_iter_discard(&msg->msg_iter, ITER_DEST, count); - return xs_sock_recv_cmsg(sock, msg, flags); + return xs_sock_recvmsg(sock, msg, flags, 0); } #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE -- 2.47.1

3 months, 1 week

1
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FAILED: patch "[PATCH] drm/sched: Remove optimization that causes hang when killing" 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 15f77764e90a713ee3916ca424757688e4f565b9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025072854-backlog-freeness-4f50@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 15f77764e90a713ee3916ca424757688e4f565b9 Mon Sep 17 00:00:00 2001 From: "Lin.Cao" <lincao12(a)amd.com> Date: Thu, 17 Jul 2025 16:44:53 +0800 Subject: [PATCH] drm/sched: Remove optimization that causes hang when killing dependent jobs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When application A submits jobs and application B submits a job with a dependency on A's fence, the normal flow wakes up the scheduler after processing each job. However, the optimization in drm_sched_entity_add_dependency_cb() uses a callback that only clears dependencies without waking up the scheduler. When application A is killed before its jobs can run, the callback gets triggered but only clears the dependency without waking up the scheduler, causing the scheduler to enter sleep state and application B to hang. Remove the optimization by deleting drm_sched_entity_clear_dep() and its usage, ensuring the scheduler is always woken up when dependencies are cleared. Fixes: 777dbd458c89 ("drm/amdgpu: drop a dummy wakeup scheduler") Cc: stable(a)vger.kernel.org # v4.6+ Signed-off-by: Lin.Cao <lincao12(a)amd.com> Reviewed-by: Christian König <christian.koenig(a)amd.com> Signed-off-by: Philipp Stanner <phasta(a)kernel.org> Link: https://lore.kernel.org/r/20250717084453.921097-1-lincao12@amd.com diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index e671aa241720..ac678de7fe5e 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -355,17 +355,6 @@ void drm_sched_entity_destroy(struct drm_sched_entity *entity) } EXPORT_SYMBOL(drm_sched_entity_destroy); -/* drm_sched_entity_clear_dep - callback to clear the entities dependency */ -static void drm_sched_entity_clear_dep(struct dma_fence *f, - struct dma_fence_cb *cb) -{ - struct drm_sched_entity *entity = - container_of(cb, struct drm_sched_entity, cb); - - entity->dependency = NULL; - dma_fence_put(f); -} - /* * drm_sched_entity_wakeup - callback to clear the entity's dependency and * wake up the scheduler @@ -376,7 +365,8 @@ static void drm_sched_entity_wakeup(struct dma_fence *f, struct drm_sched_entity *entity = container_of(cb, struct drm_sched_entity, cb); - drm_sched_entity_clear_dep(f, cb); + entity->dependency = NULL; + dma_fence_put(f); drm_sched_wakeup(entity->rq->sched); } @@ -429,13 +419,6 @@ static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity) fence = dma_fence_get(&s_fence->scheduled); dma_fence_put(entity->dependency); entity->dependency = fence; - if (!dma_fence_add_callback(fence, &entity->cb, - drm_sched_entity_clear_dep)) - return true; - - /* Ignore it when it is already scheduled */ - dma_fence_put(fence); - return false; } if (!dma_fence_add_callback(entity->dependency, &entity->cb,

3 months, 1 week

2
1
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FAILED: patch "[PATCH] drm/sched: Remove optimization that causes hang when killing" 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 15f77764e90a713ee3916ca424757688e4f565b9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025072853-startup-unwomanly-7e1c@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 15f77764e90a713ee3916ca424757688e4f565b9 Mon Sep 17 00:00:00 2001 From: "Lin.Cao" <lincao12(a)amd.com> Date: Thu, 17 Jul 2025 16:44:53 +0800 Subject: [PATCH] drm/sched: Remove optimization that causes hang when killing dependent jobs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When application A submits jobs and application B submits a job with a dependency on A's fence, the normal flow wakes up the scheduler after processing each job. However, the optimization in drm_sched_entity_add_dependency_cb() uses a callback that only clears dependencies without waking up the scheduler. When application A is killed before its jobs can run, the callback gets triggered but only clears the dependency without waking up the scheduler, causing the scheduler to enter sleep state and application B to hang. Remove the optimization by deleting drm_sched_entity_clear_dep() and its usage, ensuring the scheduler is always woken up when dependencies are cleared. Fixes: 777dbd458c89 ("drm/amdgpu: drop a dummy wakeup scheduler") Cc: stable(a)vger.kernel.org # v4.6+ Signed-off-by: Lin.Cao <lincao12(a)amd.com> Reviewed-by: Christian König <christian.koenig(a)amd.com> Signed-off-by: Philipp Stanner <phasta(a)kernel.org> Link: https://lore.kernel.org/r/20250717084453.921097-1-lincao12@amd.com diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index e671aa241720..ac678de7fe5e 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -355,17 +355,6 @@ void drm_sched_entity_destroy(struct drm_sched_entity *entity) } EXPORT_SYMBOL(drm_sched_entity_destroy); -/* drm_sched_entity_clear_dep - callback to clear the entities dependency */ -static void drm_sched_entity_clear_dep(struct dma_fence *f, - struct dma_fence_cb *cb) -{ - struct drm_sched_entity *entity = - container_of(cb, struct drm_sched_entity, cb); - - entity->dependency = NULL; - dma_fence_put(f); -} - /* * drm_sched_entity_wakeup - callback to clear the entity's dependency and * wake up the scheduler @@ -376,7 +365,8 @@ static void drm_sched_entity_wakeup(struct dma_fence *f, struct drm_sched_entity *entity = container_of(cb, struct drm_sched_entity, cb); - drm_sched_entity_clear_dep(f, cb); + entity->dependency = NULL; + dma_fence_put(f); drm_sched_wakeup(entity->rq->sched); } @@ -429,13 +419,6 @@ static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity) fence = dma_fence_get(&s_fence->scheduled); dma_fence_put(entity->dependency); entity->dependency = fence; - if (!dma_fence_add_callback(fence, &entity->cb, - drm_sched_entity_clear_dep)) - return true; - - /* Ignore it when it is already scheduled */ - dma_fence_put(fence); - return false; } if (!dma_fence_add_callback(entity->dependency, &entity->cb,

3 months, 1 week

2
1
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FAILED: patch "[PATCH] drm/sched: Remove optimization that causes hang when killing" 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 15f77764e90a713ee3916ca424757688e4f565b9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025072852-shrivel-theorize-77f8@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 15f77764e90a713ee3916ca424757688e4f565b9 Mon Sep 17 00:00:00 2001 From: "Lin.Cao" <lincao12(a)amd.com> Date: Thu, 17 Jul 2025 16:44:53 +0800 Subject: [PATCH] drm/sched: Remove optimization that causes hang when killing dependent jobs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When application A submits jobs and application B submits a job with a dependency on A's fence, the normal flow wakes up the scheduler after processing each job. However, the optimization in drm_sched_entity_add_dependency_cb() uses a callback that only clears dependencies without waking up the scheduler. When application A is killed before its jobs can run, the callback gets triggered but only clears the dependency without waking up the scheduler, causing the scheduler to enter sleep state and application B to hang. Remove the optimization by deleting drm_sched_entity_clear_dep() and its usage, ensuring the scheduler is always woken up when dependencies are cleared. Fixes: 777dbd458c89 ("drm/amdgpu: drop a dummy wakeup scheduler") Cc: stable(a)vger.kernel.org # v4.6+ Signed-off-by: Lin.Cao <lincao12(a)amd.com> Reviewed-by: Christian König <christian.koenig(a)amd.com> Signed-off-by: Philipp Stanner <phasta(a)kernel.org> Link: https://lore.kernel.org/r/20250717084453.921097-1-lincao12@amd.com diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index e671aa241720..ac678de7fe5e 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -355,17 +355,6 @@ void drm_sched_entity_destroy(struct drm_sched_entity *entity) } EXPORT_SYMBOL(drm_sched_entity_destroy); -/* drm_sched_entity_clear_dep - callback to clear the entities dependency */ -static void drm_sched_entity_clear_dep(struct dma_fence *f, - struct dma_fence_cb *cb) -{ - struct drm_sched_entity *entity = - container_of(cb, struct drm_sched_entity, cb); - - entity->dependency = NULL; - dma_fence_put(f); -} - /* * drm_sched_entity_wakeup - callback to clear the entity's dependency and * wake up the scheduler @@ -376,7 +365,8 @@ static void drm_sched_entity_wakeup(struct dma_fence *f, struct drm_sched_entity *entity = container_of(cb, struct drm_sched_entity, cb); - drm_sched_entity_clear_dep(f, cb); + entity->dependency = NULL; + dma_fence_put(f); drm_sched_wakeup(entity->rq->sched); } @@ -429,13 +419,6 @@ static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity) fence = dma_fence_get(&s_fence->scheduled); dma_fence_put(entity->dependency); entity->dependency = fence; - if (!dma_fence_add_callback(fence, &entity->cb, - drm_sched_entity_clear_dep)) - return true; - - /* Ignore it when it is already scheduled */ - dma_fence_put(fence); - return false; } if (!dma_fence_add_callback(entity->dependency, &entity->cb,

3 months, 1 week

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FAILED: patch "[PATCH] mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-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-5.4.y git checkout FETCH_HEAD git cherry-pick -x 694d6b99923eb05a8fd188be44e26077d19f0e21 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025072811-ethanol-arbitrary-a664@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 694d6b99923eb05a8fd188be44e26077d19f0e21 Mon Sep 17 00:00:00 2001 From: Harry Yoo <harry.yoo(a)oracle.com> Date: Fri, 4 Jul 2025 19:30:53 +0900 Subject: [PATCH] mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n Commit 48b4800a1c6a ("zsmalloc: page migration support") added support for migrating zsmalloc pages using the movable_operations migration framework. However, the commit did not take into account that zsmalloc supports migration only when CONFIG_COMPACTION is enabled. Tracing shows that zsmalloc was still passing the __GFP_MOVABLE flag even when compaction is not supported. This can result in unmovable pages being allocated from movable page blocks (even without stealing page blocks), ZONE_MOVABLE and CMA area. Possible user visible effects: - Some ZONE_MOVABLE memory can be not actually movable - CMA allocation can fail because of this - Increased memory fragmentation due to ignoring the page mobility grouping feature I'm not really sure who uses kernels without compaction support, though :( To fix this, clear the __GFP_MOVABLE flag when !IS_ENABLED(CONFIG_COMPACTION). Link: https://lkml.kernel.org/r/20250704103053.6913-1-harry.yoo@oracle.com Fixes: 48b4800a1c6a ("zsmalloc: page migration support") Signed-off-by: Harry Yoo <harry.yoo(a)oracle.com> Acked-by: David Hildenbrand <david(a)redhat.com> Reviewed-by: Sergey Senozhatsky <senozhatsky(a)chromium.org> Cc: Minchan Kim <minchan(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 999b513c7fdf..f3e2215f95eb 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1043,6 +1043,9 @@ static struct zspage *alloc_zspage(struct zs_pool *pool, if (!zspage) return NULL; + if (!IS_ENABLED(CONFIG_COMPACTION)) + gfp &= ~__GFP_MOVABLE; + zspage->magic = ZSPAGE_MAGIC; zspage->pool = pool; zspage->class = class->index;

3 months, 1 week

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FAILED: patch "[PATCH] mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-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-5.10.y git checkout FETCH_HEAD git cherry-pick -x 694d6b99923eb05a8fd188be44e26077d19f0e21 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025072810-footgear-grumpily-4fd5@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 694d6b99923eb05a8fd188be44e26077d19f0e21 Mon Sep 17 00:00:00 2001 From: Harry Yoo <harry.yoo(a)oracle.com> Date: Fri, 4 Jul 2025 19:30:53 +0900 Subject: [PATCH] mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n Commit 48b4800a1c6a ("zsmalloc: page migration support") added support for migrating zsmalloc pages using the movable_operations migration framework. However, the commit did not take into account that zsmalloc supports migration only when CONFIG_COMPACTION is enabled. Tracing shows that zsmalloc was still passing the __GFP_MOVABLE flag even when compaction is not supported. This can result in unmovable pages being allocated from movable page blocks (even without stealing page blocks), ZONE_MOVABLE and CMA area. Possible user visible effects: - Some ZONE_MOVABLE memory can be not actually movable - CMA allocation can fail because of this - Increased memory fragmentation due to ignoring the page mobility grouping feature I'm not really sure who uses kernels without compaction support, though :( To fix this, clear the __GFP_MOVABLE flag when !IS_ENABLED(CONFIG_COMPACTION). Link: https://lkml.kernel.org/r/20250704103053.6913-1-harry.yoo@oracle.com Fixes: 48b4800a1c6a ("zsmalloc: page migration support") Signed-off-by: Harry Yoo <harry.yoo(a)oracle.com> Acked-by: David Hildenbrand <david(a)redhat.com> Reviewed-by: Sergey Senozhatsky <senozhatsky(a)chromium.org> Cc: Minchan Kim <minchan(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 999b513c7fdf..f3e2215f95eb 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1043,6 +1043,9 @@ static struct zspage *alloc_zspage(struct zs_pool *pool, if (!zspage) return NULL; + if (!IS_ENABLED(CONFIG_COMPACTION)) + gfp &= ~__GFP_MOVABLE; + zspage->magic = ZSPAGE_MAGIC; zspage->pool = pool; zspage->class = class->index;

3 months, 1 week

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[PATCH v3 1/1] mm: fix a UAF when vma->mm is freed after vma->vm_refcnt got dropped

by Suren Baghdasaryan

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. Fixes: 3104138517fc ("mm: make vma cache SLAB_TYPESAFE_BY_RCU") Reported-by: Jann Horn <jannh(a)google.com> Closes: https://lore.kernel.org/all/CAG48ez0-deFbVH=E3jbkWx=X3uVbd8nWeo6kbJPQ0KoUD+… Signed-off-by: Suren Baghdasaryan <surenb(a)google.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Acked-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: <stable(a)vger.kernel.org> --- Changes since v2 [1] - Addressed Lorenzo's nits, per Lorenzo Stoakes - Added a warning comment for vma_start_read() - Added Reviewed-by and Acked-by, per Vlastimil Babka and Lorenzo Stoakes Notes: - Applies cleanly over mm-unstable after reverting previous version of this patch [1]. - Should be applied to 6.15 and 6.16 but these branches do not have lock_next_vma() function, so the change in lock_next_vma() should be skipped when applying to those branches. [1] https://lore.kernel.org/all/20250728175355.2282375-1-surenb@google.com/ include/linux/mmap_lock.h | 30 ++++++++++++++++++++++++++++++ mm/mmap_lock.c | 10 +++------- 2 files changed, 33 insertions(+), 7 deletions(-) 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; /* -- 2.50.1.487.gc89ff58d15-goog

3 months, 1 week

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