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FAILED: patch "[PATCH] mm: fix uprobe pte be overwritten when expanding vma" 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 2b12d06c37fd3a394376f42f026a7478d826ed63 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062015-email-sulphuric-0b7f@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2b12d06c37fd3a394376f42f026a7478d826ed63 Mon Sep 17 00:00:00 2001 From: Pu Lehui <pulehui(a)huawei.com> Date: Thu, 29 May 2025 15:56:47 +0000 Subject: [PATCH] mm: fix uprobe pte be overwritten when expanding vma Patch series "Fix uprobe pte be overwritten when expanding vma". This patch (of 4): We encountered a BUG alert triggered by Syzkaller as follows: BUG: Bad rss-counter state mm:00000000b4a60fca type:MM_ANONPAGES val:1 And we can reproduce it with the following steps: 1. register uprobe on file at zero offset 2. mmap the file at zero offset: addr1 = mmap(NULL, 2 * 4096, PROT_NONE, MAP_PRIVATE, fd, 0); 3. mremap part of vma1 to new vma2: addr2 = mremap(addr1, 4096, 2 * 4096, MREMAP_MAYMOVE); 4. mremap back to orig addr1: mremap(addr2, 4096, 4096, MREMAP_MAYMOVE | MREMAP_FIXED, addr1); In step 3, the vma1 range [addr1, addr1 + 4096] will be remap to new vma2 with range [addr2, addr2 + 8192], and remap uprobe anon page from the vma1 to vma2, then unmap the vma1 range [addr1, addr1 + 4096]. In step 4, the vma2 range [addr2, addr2 + 4096] will be remap back to the addr range [addr1, addr1 + 4096]. Since the addr range [addr1 + 4096, addr1 + 8192] still maps the file, it will take vma_merge_new_range to expand the range, and then do uprobe_mmap in vma_complete. Since the merged vma pgoff is also zero offset, it will install uprobe anon page to the merged vma. However, the upcomming move_page_tables step, which use set_pte_at to remap the vma2 uprobe pte to the merged vma, will overwrite the newly uprobe pte in the merged vma, and lead that pte to be orphan. Since the uprobe pte will be remapped to the merged vma, we can remove the unnecessary uprobe_mmap upon merged vma. This problem was first found in linux-6.6.y and also exists in the community syzkaller: https://lore.kernel.org/all/000000000000ada39605a5e71711@google.com/T/ Link: https://lkml.kernel.org/r/20250529155650.4017699-1-pulehui@huaweicloud.com Link: https://lkml.kernel.org/r/20250529155650.4017699-2-pulehui@huaweicloud.com Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Signed-off-by: Pu Lehui <pulehui(a)huawei.com> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: "Masami Hiramatsu (Google)" <mhiramat(a)kernel.org> Cc: Oleg Nesterov <oleg(a)redhat.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/vma.c b/mm/vma.c index 1c6595f282e5..b2d7c03d8aa4 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -169,6 +169,9 @@ static void init_multi_vma_prep(struct vma_prepare *vp, vp->file = vma->vm_file; if (vp->file) vp->mapping = vma->vm_file->f_mapping; + + if (vmg && vmg->skip_vma_uprobe) + vp->skip_vma_uprobe = true; } /* @@ -358,10 +361,13 @@ static void vma_complete(struct vma_prepare *vp, struct vma_iterator *vmi, if (vp->file) { i_mmap_unlock_write(vp->mapping); - uprobe_mmap(vp->vma); - if (vp->adj_next) - uprobe_mmap(vp->adj_next); + if (!vp->skip_vma_uprobe) { + uprobe_mmap(vp->vma); + + if (vp->adj_next) + uprobe_mmap(vp->adj_next); + } } if (vp->remove) { @@ -1823,6 +1829,14 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, faulted_in_anon_vma = false; } + /* + * If the VMA we are copying might contain a uprobe PTE, ensure + * that we do not establish one upon merge. Otherwise, when mremap() + * moves page tables, it will orphan the newly created PTE. + */ + if (vma->vm_file) + vmg.skip_vma_uprobe = true; + new_vma = find_vma_prev(mm, addr, &vmg.prev); if (new_vma && new_vma->vm_start < addr + len) return NULL; /* should never get here */ diff --git a/mm/vma.h b/mm/vma.h index 9a8af9be29a8..0db066e7a45d 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -19,6 +19,8 @@ struct vma_prepare { struct vm_area_struct *insert; struct vm_area_struct *remove; struct vm_area_struct *remove2; + + bool skip_vma_uprobe :1; }; struct unlink_vma_file_batch { @@ -120,6 +122,11 @@ struct vma_merge_struct { */ bool give_up_on_oom :1; + /* + * If set, skip uprobe_mmap upon merged vma. + */ + bool skip_vma_uprobe :1; + /* Internal flags set during merge process: */ /*

2 months, 4 weeks

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FAILED: patch "[PATCH] mm: fix uprobe pte be overwritten when expanding vma" 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 2b12d06c37fd3a394376f42f026a7478d826ed63 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062013-apostle-lethargic-d079@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2b12d06c37fd3a394376f42f026a7478d826ed63 Mon Sep 17 00:00:00 2001 From: Pu Lehui <pulehui(a)huawei.com> Date: Thu, 29 May 2025 15:56:47 +0000 Subject: [PATCH] mm: fix uprobe pte be overwritten when expanding vma Patch series "Fix uprobe pte be overwritten when expanding vma". This patch (of 4): We encountered a BUG alert triggered by Syzkaller as follows: BUG: Bad rss-counter state mm:00000000b4a60fca type:MM_ANONPAGES val:1 And we can reproduce it with the following steps: 1. register uprobe on file at zero offset 2. mmap the file at zero offset: addr1 = mmap(NULL, 2 * 4096, PROT_NONE, MAP_PRIVATE, fd, 0); 3. mremap part of vma1 to new vma2: addr2 = mremap(addr1, 4096, 2 * 4096, MREMAP_MAYMOVE); 4. mremap back to orig addr1: mremap(addr2, 4096, 4096, MREMAP_MAYMOVE | MREMAP_FIXED, addr1); In step 3, the vma1 range [addr1, addr1 + 4096] will be remap to new vma2 with range [addr2, addr2 + 8192], and remap uprobe anon page from the vma1 to vma2, then unmap the vma1 range [addr1, addr1 + 4096]. In step 4, the vma2 range [addr2, addr2 + 4096] will be remap back to the addr range [addr1, addr1 + 4096]. Since the addr range [addr1 + 4096, addr1 + 8192] still maps the file, it will take vma_merge_new_range to expand the range, and then do uprobe_mmap in vma_complete. Since the merged vma pgoff is also zero offset, it will install uprobe anon page to the merged vma. However, the upcomming move_page_tables step, which use set_pte_at to remap the vma2 uprobe pte to the merged vma, will overwrite the newly uprobe pte in the merged vma, and lead that pte to be orphan. Since the uprobe pte will be remapped to the merged vma, we can remove the unnecessary uprobe_mmap upon merged vma. This problem was first found in linux-6.6.y and also exists in the community syzkaller: https://lore.kernel.org/all/000000000000ada39605a5e71711@google.com/T/ Link: https://lkml.kernel.org/r/20250529155650.4017699-1-pulehui@huaweicloud.com Link: https://lkml.kernel.org/r/20250529155650.4017699-2-pulehui@huaweicloud.com Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Signed-off-by: Pu Lehui <pulehui(a)huawei.com> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: "Masami Hiramatsu (Google)" <mhiramat(a)kernel.org> Cc: Oleg Nesterov <oleg(a)redhat.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/vma.c b/mm/vma.c index 1c6595f282e5..b2d7c03d8aa4 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -169,6 +169,9 @@ static void init_multi_vma_prep(struct vma_prepare *vp, vp->file = vma->vm_file; if (vp->file) vp->mapping = vma->vm_file->f_mapping; + + if (vmg && vmg->skip_vma_uprobe) + vp->skip_vma_uprobe = true; } /* @@ -358,10 +361,13 @@ static void vma_complete(struct vma_prepare *vp, struct vma_iterator *vmi, if (vp->file) { i_mmap_unlock_write(vp->mapping); - uprobe_mmap(vp->vma); - if (vp->adj_next) - uprobe_mmap(vp->adj_next); + if (!vp->skip_vma_uprobe) { + uprobe_mmap(vp->vma); + + if (vp->adj_next) + uprobe_mmap(vp->adj_next); + } } if (vp->remove) { @@ -1823,6 +1829,14 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, faulted_in_anon_vma = false; } + /* + * If the VMA we are copying might contain a uprobe PTE, ensure + * that we do not establish one upon merge. Otherwise, when mremap() + * moves page tables, it will orphan the newly created PTE. + */ + if (vma->vm_file) + vmg.skip_vma_uprobe = true; + new_vma = find_vma_prev(mm, addr, &vmg.prev); if (new_vma && new_vma->vm_start < addr + len) return NULL; /* should never get here */ diff --git a/mm/vma.h b/mm/vma.h index 9a8af9be29a8..0db066e7a45d 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -19,6 +19,8 @@ struct vma_prepare { struct vm_area_struct *insert; struct vm_area_struct *remove; struct vm_area_struct *remove2; + + bool skip_vma_uprobe :1; }; struct unlink_vma_file_batch { @@ -120,6 +122,11 @@ struct vma_merge_struct { */ bool give_up_on_oom :1; + /* + * If set, skip uprobe_mmap upon merged vma. + */ + bool skip_vma_uprobe :1; + /* Internal flags set during merge process: */ /*

2 months, 4 weeks

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FAILED: patch "[PATCH] mm: fix uprobe pte be overwritten when expanding vma" 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 2b12d06c37fd3a394376f42f026a7478d826ed63 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062012-judge-nemesis-5f60@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2b12d06c37fd3a394376f42f026a7478d826ed63 Mon Sep 17 00:00:00 2001 From: Pu Lehui <pulehui(a)huawei.com> Date: Thu, 29 May 2025 15:56:47 +0000 Subject: [PATCH] mm: fix uprobe pte be overwritten when expanding vma Patch series "Fix uprobe pte be overwritten when expanding vma". This patch (of 4): We encountered a BUG alert triggered by Syzkaller as follows: BUG: Bad rss-counter state mm:00000000b4a60fca type:MM_ANONPAGES val:1 And we can reproduce it with the following steps: 1. register uprobe on file at zero offset 2. mmap the file at zero offset: addr1 = mmap(NULL, 2 * 4096, PROT_NONE, MAP_PRIVATE, fd, 0); 3. mremap part of vma1 to new vma2: addr2 = mremap(addr1, 4096, 2 * 4096, MREMAP_MAYMOVE); 4. mremap back to orig addr1: mremap(addr2, 4096, 4096, MREMAP_MAYMOVE | MREMAP_FIXED, addr1); In step 3, the vma1 range [addr1, addr1 + 4096] will be remap to new vma2 with range [addr2, addr2 + 8192], and remap uprobe anon page from the vma1 to vma2, then unmap the vma1 range [addr1, addr1 + 4096]. In step 4, the vma2 range [addr2, addr2 + 4096] will be remap back to the addr range [addr1, addr1 + 4096]. Since the addr range [addr1 + 4096, addr1 + 8192] still maps the file, it will take vma_merge_new_range to expand the range, and then do uprobe_mmap in vma_complete. Since the merged vma pgoff is also zero offset, it will install uprobe anon page to the merged vma. However, the upcomming move_page_tables step, which use set_pte_at to remap the vma2 uprobe pte to the merged vma, will overwrite the newly uprobe pte in the merged vma, and lead that pte to be orphan. Since the uprobe pte will be remapped to the merged vma, we can remove the unnecessary uprobe_mmap upon merged vma. This problem was first found in linux-6.6.y and also exists in the community syzkaller: https://lore.kernel.org/all/000000000000ada39605a5e71711@google.com/T/ Link: https://lkml.kernel.org/r/20250529155650.4017699-1-pulehui@huaweicloud.com Link: https://lkml.kernel.org/r/20250529155650.4017699-2-pulehui@huaweicloud.com Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Signed-off-by: Pu Lehui <pulehui(a)huawei.com> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: "Masami Hiramatsu (Google)" <mhiramat(a)kernel.org> Cc: Oleg Nesterov <oleg(a)redhat.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/vma.c b/mm/vma.c index 1c6595f282e5..b2d7c03d8aa4 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -169,6 +169,9 @@ static void init_multi_vma_prep(struct vma_prepare *vp, vp->file = vma->vm_file; if (vp->file) vp->mapping = vma->vm_file->f_mapping; + + if (vmg && vmg->skip_vma_uprobe) + vp->skip_vma_uprobe = true; } /* @@ -358,10 +361,13 @@ static void vma_complete(struct vma_prepare *vp, struct vma_iterator *vmi, if (vp->file) { i_mmap_unlock_write(vp->mapping); - uprobe_mmap(vp->vma); - if (vp->adj_next) - uprobe_mmap(vp->adj_next); + if (!vp->skip_vma_uprobe) { + uprobe_mmap(vp->vma); + + if (vp->adj_next) + uprobe_mmap(vp->adj_next); + } } if (vp->remove) { @@ -1823,6 +1829,14 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, faulted_in_anon_vma = false; } + /* + * If the VMA we are copying might contain a uprobe PTE, ensure + * that we do not establish one upon merge. Otherwise, when mremap() + * moves page tables, it will orphan the newly created PTE. + */ + if (vma->vm_file) + vmg.skip_vma_uprobe = true; + new_vma = find_vma_prev(mm, addr, &vmg.prev); if (new_vma && new_vma->vm_start < addr + len) return NULL; /* should never get here */ diff --git a/mm/vma.h b/mm/vma.h index 9a8af9be29a8..0db066e7a45d 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -19,6 +19,8 @@ struct vma_prepare { struct vm_area_struct *insert; struct vm_area_struct *remove; struct vm_area_struct *remove2; + + bool skip_vma_uprobe :1; }; struct unlink_vma_file_batch { @@ -120,6 +122,11 @@ struct vma_merge_struct { */ bool give_up_on_oom :1; + /* + * If set, skip uprobe_mmap upon merged vma. + */ + bool skip_vma_uprobe :1; + /* Internal flags set during merge process: */ /*

2 months, 4 weeks

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FAILED: patch "[PATCH] mm: fix uprobe pte be overwritten when expanding vma" 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 2b12d06c37fd3a394376f42f026a7478d826ed63 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062011-earache-whenever-2435@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2b12d06c37fd3a394376f42f026a7478d826ed63 Mon Sep 17 00:00:00 2001 From: Pu Lehui <pulehui(a)huawei.com> Date: Thu, 29 May 2025 15:56:47 +0000 Subject: [PATCH] mm: fix uprobe pte be overwritten when expanding vma Patch series "Fix uprobe pte be overwritten when expanding vma". This patch (of 4): We encountered a BUG alert triggered by Syzkaller as follows: BUG: Bad rss-counter state mm:00000000b4a60fca type:MM_ANONPAGES val:1 And we can reproduce it with the following steps: 1. register uprobe on file at zero offset 2. mmap the file at zero offset: addr1 = mmap(NULL, 2 * 4096, PROT_NONE, MAP_PRIVATE, fd, 0); 3. mremap part of vma1 to new vma2: addr2 = mremap(addr1, 4096, 2 * 4096, MREMAP_MAYMOVE); 4. mremap back to orig addr1: mremap(addr2, 4096, 4096, MREMAP_MAYMOVE | MREMAP_FIXED, addr1); In step 3, the vma1 range [addr1, addr1 + 4096] will be remap to new vma2 with range [addr2, addr2 + 8192], and remap uprobe anon page from the vma1 to vma2, then unmap the vma1 range [addr1, addr1 + 4096]. In step 4, the vma2 range [addr2, addr2 + 4096] will be remap back to the addr range [addr1, addr1 + 4096]. Since the addr range [addr1 + 4096, addr1 + 8192] still maps the file, it will take vma_merge_new_range to expand the range, and then do uprobe_mmap in vma_complete. Since the merged vma pgoff is also zero offset, it will install uprobe anon page to the merged vma. However, the upcomming move_page_tables step, which use set_pte_at to remap the vma2 uprobe pte to the merged vma, will overwrite the newly uprobe pte in the merged vma, and lead that pte to be orphan. Since the uprobe pte will be remapped to the merged vma, we can remove the unnecessary uprobe_mmap upon merged vma. This problem was first found in linux-6.6.y and also exists in the community syzkaller: https://lore.kernel.org/all/000000000000ada39605a5e71711@google.com/T/ Link: https://lkml.kernel.org/r/20250529155650.4017699-1-pulehui@huaweicloud.com Link: https://lkml.kernel.org/r/20250529155650.4017699-2-pulehui@huaweicloud.com Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Signed-off-by: Pu Lehui <pulehui(a)huawei.com> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: "Masami Hiramatsu (Google)" <mhiramat(a)kernel.org> Cc: Oleg Nesterov <oleg(a)redhat.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/vma.c b/mm/vma.c index 1c6595f282e5..b2d7c03d8aa4 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -169,6 +169,9 @@ static void init_multi_vma_prep(struct vma_prepare *vp, vp->file = vma->vm_file; if (vp->file) vp->mapping = vma->vm_file->f_mapping; + + if (vmg && vmg->skip_vma_uprobe) + vp->skip_vma_uprobe = true; } /* @@ -358,10 +361,13 @@ static void vma_complete(struct vma_prepare *vp, struct vma_iterator *vmi, if (vp->file) { i_mmap_unlock_write(vp->mapping); - uprobe_mmap(vp->vma); - if (vp->adj_next) - uprobe_mmap(vp->adj_next); + if (!vp->skip_vma_uprobe) { + uprobe_mmap(vp->vma); + + if (vp->adj_next) + uprobe_mmap(vp->adj_next); + } } if (vp->remove) { @@ -1823,6 +1829,14 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, faulted_in_anon_vma = false; } + /* + * If the VMA we are copying might contain a uprobe PTE, ensure + * that we do not establish one upon merge. Otherwise, when mremap() + * moves page tables, it will orphan the newly created PTE. + */ + if (vma->vm_file) + vmg.skip_vma_uprobe = true; + new_vma = find_vma_prev(mm, addr, &vmg.prev); if (new_vma && new_vma->vm_start < addr + len) return NULL; /* should never get here */ diff --git a/mm/vma.h b/mm/vma.h index 9a8af9be29a8..0db066e7a45d 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -19,6 +19,8 @@ struct vma_prepare { struct vm_area_struct *insert; struct vm_area_struct *remove; struct vm_area_struct *remove2; + + bool skip_vma_uprobe :1; }; struct unlink_vma_file_batch { @@ -120,6 +122,11 @@ struct vma_merge_struct { */ bool give_up_on_oom :1; + /* + * If set, skip uprobe_mmap upon merged vma. + */ + bool skip_vma_uprobe :1; + /* Internal flags set during merge process: */ /*

2 months, 4 weeks

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FAILED: patch "[PATCH] mm: fix uprobe pte be overwritten when expanding vma" 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 2b12d06c37fd3a394376f42f026a7478d826ed63 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062009-customs-outskirts-5826@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2b12d06c37fd3a394376f42f026a7478d826ed63 Mon Sep 17 00:00:00 2001 From: Pu Lehui <pulehui(a)huawei.com> Date: Thu, 29 May 2025 15:56:47 +0000 Subject: [PATCH] mm: fix uprobe pte be overwritten when expanding vma Patch series "Fix uprobe pte be overwritten when expanding vma". This patch (of 4): We encountered a BUG alert triggered by Syzkaller as follows: BUG: Bad rss-counter state mm:00000000b4a60fca type:MM_ANONPAGES val:1 And we can reproduce it with the following steps: 1. register uprobe on file at zero offset 2. mmap the file at zero offset: addr1 = mmap(NULL, 2 * 4096, PROT_NONE, MAP_PRIVATE, fd, 0); 3. mremap part of vma1 to new vma2: addr2 = mremap(addr1, 4096, 2 * 4096, MREMAP_MAYMOVE); 4. mremap back to orig addr1: mremap(addr2, 4096, 4096, MREMAP_MAYMOVE | MREMAP_FIXED, addr1); In step 3, the vma1 range [addr1, addr1 + 4096] will be remap to new vma2 with range [addr2, addr2 + 8192], and remap uprobe anon page from the vma1 to vma2, then unmap the vma1 range [addr1, addr1 + 4096]. In step 4, the vma2 range [addr2, addr2 + 4096] will be remap back to the addr range [addr1, addr1 + 4096]. Since the addr range [addr1 + 4096, addr1 + 8192] still maps the file, it will take vma_merge_new_range to expand the range, and then do uprobe_mmap in vma_complete. Since the merged vma pgoff is also zero offset, it will install uprobe anon page to the merged vma. However, the upcomming move_page_tables step, which use set_pte_at to remap the vma2 uprobe pte to the merged vma, will overwrite the newly uprobe pte in the merged vma, and lead that pte to be orphan. Since the uprobe pte will be remapped to the merged vma, we can remove the unnecessary uprobe_mmap upon merged vma. This problem was first found in linux-6.6.y and also exists in the community syzkaller: https://lore.kernel.org/all/000000000000ada39605a5e71711@google.com/T/ Link: https://lkml.kernel.org/r/20250529155650.4017699-1-pulehui@huaweicloud.com Link: https://lkml.kernel.org/r/20250529155650.4017699-2-pulehui@huaweicloud.com Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Signed-off-by: Pu Lehui <pulehui(a)huawei.com> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: "Masami Hiramatsu (Google)" <mhiramat(a)kernel.org> Cc: Oleg Nesterov <oleg(a)redhat.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/vma.c b/mm/vma.c index 1c6595f282e5..b2d7c03d8aa4 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -169,6 +169,9 @@ static void init_multi_vma_prep(struct vma_prepare *vp, vp->file = vma->vm_file; if (vp->file) vp->mapping = vma->vm_file->f_mapping; + + if (vmg && vmg->skip_vma_uprobe) + vp->skip_vma_uprobe = true; } /* @@ -358,10 +361,13 @@ static void vma_complete(struct vma_prepare *vp, struct vma_iterator *vmi, if (vp->file) { i_mmap_unlock_write(vp->mapping); - uprobe_mmap(vp->vma); - if (vp->adj_next) - uprobe_mmap(vp->adj_next); + if (!vp->skip_vma_uprobe) { + uprobe_mmap(vp->vma); + + if (vp->adj_next) + uprobe_mmap(vp->adj_next); + } } if (vp->remove) { @@ -1823,6 +1829,14 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, faulted_in_anon_vma = false; } + /* + * If the VMA we are copying might contain a uprobe PTE, ensure + * that we do not establish one upon merge. Otherwise, when mremap() + * moves page tables, it will orphan the newly created PTE. + */ + if (vma->vm_file) + vmg.skip_vma_uprobe = true; + new_vma = find_vma_prev(mm, addr, &vmg.prev); if (new_vma && new_vma->vm_start < addr + len) return NULL; /* should never get here */ diff --git a/mm/vma.h b/mm/vma.h index 9a8af9be29a8..0db066e7a45d 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -19,6 +19,8 @@ struct vma_prepare { struct vm_area_struct *insert; struct vm_area_struct *remove; struct vm_area_struct *remove2; + + bool skip_vma_uprobe :1; }; struct unlink_vma_file_batch { @@ -120,6 +122,11 @@ struct vma_merge_struct { */ bool give_up_on_oom :1; + /* + * If set, skip uprobe_mmap upon merged vma. + */ + bool skip_vma_uprobe :1; + /* Internal flags set during merge process: */ /*

2 months, 4 weeks

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FAILED: patch "[PATCH] mm: fix uprobe pte be overwritten when expanding vma" 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 2b12d06c37fd3a394376f42f026a7478d826ed63 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062008-scarcity-jaundice-0b6e@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2b12d06c37fd3a394376f42f026a7478d826ed63 Mon Sep 17 00:00:00 2001 From: Pu Lehui <pulehui(a)huawei.com> Date: Thu, 29 May 2025 15:56:47 +0000 Subject: [PATCH] mm: fix uprobe pte be overwritten when expanding vma Patch series "Fix uprobe pte be overwritten when expanding vma". This patch (of 4): We encountered a BUG alert triggered by Syzkaller as follows: BUG: Bad rss-counter state mm:00000000b4a60fca type:MM_ANONPAGES val:1 And we can reproduce it with the following steps: 1. register uprobe on file at zero offset 2. mmap the file at zero offset: addr1 = mmap(NULL, 2 * 4096, PROT_NONE, MAP_PRIVATE, fd, 0); 3. mremap part of vma1 to new vma2: addr2 = mremap(addr1, 4096, 2 * 4096, MREMAP_MAYMOVE); 4. mremap back to orig addr1: mremap(addr2, 4096, 4096, MREMAP_MAYMOVE | MREMAP_FIXED, addr1); In step 3, the vma1 range [addr1, addr1 + 4096] will be remap to new vma2 with range [addr2, addr2 + 8192], and remap uprobe anon page from the vma1 to vma2, then unmap the vma1 range [addr1, addr1 + 4096]. In step 4, the vma2 range [addr2, addr2 + 4096] will be remap back to the addr range [addr1, addr1 + 4096]. Since the addr range [addr1 + 4096, addr1 + 8192] still maps the file, it will take vma_merge_new_range to expand the range, and then do uprobe_mmap in vma_complete. Since the merged vma pgoff is also zero offset, it will install uprobe anon page to the merged vma. However, the upcomming move_page_tables step, which use set_pte_at to remap the vma2 uprobe pte to the merged vma, will overwrite the newly uprobe pte in the merged vma, and lead that pte to be orphan. Since the uprobe pte will be remapped to the merged vma, we can remove the unnecessary uprobe_mmap upon merged vma. This problem was first found in linux-6.6.y and also exists in the community syzkaller: https://lore.kernel.org/all/000000000000ada39605a5e71711@google.com/T/ Link: https://lkml.kernel.org/r/20250529155650.4017699-1-pulehui@huaweicloud.com Link: https://lkml.kernel.org/r/20250529155650.4017699-2-pulehui@huaweicloud.com Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Signed-off-by: Pu Lehui <pulehui(a)huawei.com> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: "Masami Hiramatsu (Google)" <mhiramat(a)kernel.org> Cc: Oleg Nesterov <oleg(a)redhat.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/vma.c b/mm/vma.c index 1c6595f282e5..b2d7c03d8aa4 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -169,6 +169,9 @@ static void init_multi_vma_prep(struct vma_prepare *vp, vp->file = vma->vm_file; if (vp->file) vp->mapping = vma->vm_file->f_mapping; + + if (vmg && vmg->skip_vma_uprobe) + vp->skip_vma_uprobe = true; } /* @@ -358,10 +361,13 @@ static void vma_complete(struct vma_prepare *vp, struct vma_iterator *vmi, if (vp->file) { i_mmap_unlock_write(vp->mapping); - uprobe_mmap(vp->vma); - if (vp->adj_next) - uprobe_mmap(vp->adj_next); + if (!vp->skip_vma_uprobe) { + uprobe_mmap(vp->vma); + + if (vp->adj_next) + uprobe_mmap(vp->adj_next); + } } if (vp->remove) { @@ -1823,6 +1829,14 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, faulted_in_anon_vma = false; } + /* + * If the VMA we are copying might contain a uprobe PTE, ensure + * that we do not establish one upon merge. Otherwise, when mremap() + * moves page tables, it will orphan the newly created PTE. + */ + if (vma->vm_file) + vmg.skip_vma_uprobe = true; + new_vma = find_vma_prev(mm, addr, &vmg.prev); if (new_vma && new_vma->vm_start < addr + len) return NULL; /* should never get here */ diff --git a/mm/vma.h b/mm/vma.h index 9a8af9be29a8..0db066e7a45d 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -19,6 +19,8 @@ struct vma_prepare { struct vm_area_struct *insert; struct vm_area_struct *remove; struct vm_area_struct *remove2; + + bool skip_vma_uprobe :1; }; struct unlink_vma_file_batch { @@ -120,6 +122,11 @@ struct vma_merge_struct { */ bool give_up_on_oom :1; + /* + * If set, skip uprobe_mmap upon merged vma. + */ + bool skip_vma_uprobe :1; + /* Internal flags set during merge process: */ /*

2 months, 4 weeks

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FAILED: patch "[PATCH] dummycon: Trigger redraw when switching consoles with" 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 03bcbbb3995ba5df43af9aba45334e35f2dfe27b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062045-bungee-spooky-6ffe@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 03bcbbb3995ba5df43af9aba45334e35f2dfe27b Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann <tzimmermann(a)suse.de> Date: Tue, 20 May 2025 09:14:00 +0200 Subject: [PATCH] dummycon: Trigger redraw when switching consoles with deferred takeover Signal vt subsystem to redraw console when switching to dummycon with deferred takeover enabled. Makes the console switch to fbcon and displays the available output. With deferred takeover enabled, dummycon acts as the placeholder until the first output to the console happens. At that point, fbcon takes over. If the output happens while dummycon is not active, it cannot inform fbcon. This is the case if the vt subsystem runs in graphics mode. A typical graphical boot starts plymouth, a display manager and a compositor; all while leaving out dummycon. Switching to a text-mode console leaves the console with dummycon even if a getty terminal has been started. Returning true from dummycon's con_switch helper signals the vt subsystem to redraw the screen. If there's output available dummycon's con_putc{s} helpers trigger deferred takeover of fbcon, which sets a display mode and displays the output. If no output is available, dummycon remains active. v2: - make the comment slightly more verbose (Javier) Signed-off-by: Thomas Zimmermann <tzimmermann(a)suse.de> Reported-by: Andrei Borzenkov <arvidjaar(a)gmail.com> Closes: https://bugzilla.suse.com/show_bug.cgi?id=1242191 Tested-by: Andrei Borzenkov <arvidjaar(a)gmail.com> Acked-by: Javier Martinez Canillas <javierm(a)redhat.com> Fixes: 83d83bebf401 ("console/fbcon: Add support for deferred console takeover") Cc: Hans de Goede <hdegoede(a)redhat.com> Cc: linux-fbdev(a)vger.kernel.org Cc: dri-devel(a)lists.freedesktop.org Cc: <stable(a)vger.kernel.org> # v4.19+ Link: https://lore.kernel.org/r/20250520071418.8462-1-tzimmermann@suse.de diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c index 139049368fdc..7d02470f19b9 100644 --- a/drivers/video/console/dummycon.c +++ b/drivers/video/console/dummycon.c @@ -85,6 +85,15 @@ static bool dummycon_blank(struct vc_data *vc, enum vesa_blank_mode blank, /* Redraw, so that we get putc(s) for output done while blanked */ return true; } + +static bool dummycon_switch(struct vc_data *vc) +{ + /* + * Redraw, so that we get putc(s) for output done while switched + * away. Informs deferred consoles to take over the display. + */ + return true; +} #else static void dummycon_putc(struct vc_data *vc, u16 c, unsigned int y, unsigned int x) { } @@ -95,6 +104,10 @@ static bool dummycon_blank(struct vc_data *vc, enum vesa_blank_mode blank, { return false; } +static bool dummycon_switch(struct vc_data *vc) +{ + return false; +} #endif static const char *dummycon_startup(void) @@ -124,11 +137,6 @@ static bool dummycon_scroll(struct vc_data *vc, unsigned int top, return false; } -static bool dummycon_switch(struct vc_data *vc) -{ - return false; -} - /* * The console `switch' structure for the dummy console *

2 months, 4 weeks

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FAILED: patch "[PATCH] dummycon: Trigger redraw when switching consoles with" 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 03bcbbb3995ba5df43af9aba45334e35f2dfe27b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062042-wound-marathon-63cd@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 03bcbbb3995ba5df43af9aba45334e35f2dfe27b Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann <tzimmermann(a)suse.de> Date: Tue, 20 May 2025 09:14:00 +0200 Subject: [PATCH] dummycon: Trigger redraw when switching consoles with deferred takeover Signal vt subsystem to redraw console when switching to dummycon with deferred takeover enabled. Makes the console switch to fbcon and displays the available output. With deferred takeover enabled, dummycon acts as the placeholder until the first output to the console happens. At that point, fbcon takes over. If the output happens while dummycon is not active, it cannot inform fbcon. This is the case if the vt subsystem runs in graphics mode. A typical graphical boot starts plymouth, a display manager and a compositor; all while leaving out dummycon. Switching to a text-mode console leaves the console with dummycon even if a getty terminal has been started. Returning true from dummycon's con_switch helper signals the vt subsystem to redraw the screen. If there's output available dummycon's con_putc{s} helpers trigger deferred takeover of fbcon, which sets a display mode and displays the output. If no output is available, dummycon remains active. v2: - make the comment slightly more verbose (Javier) Signed-off-by: Thomas Zimmermann <tzimmermann(a)suse.de> Reported-by: Andrei Borzenkov <arvidjaar(a)gmail.com> Closes: https://bugzilla.suse.com/show_bug.cgi?id=1242191 Tested-by: Andrei Borzenkov <arvidjaar(a)gmail.com> Acked-by: Javier Martinez Canillas <javierm(a)redhat.com> Fixes: 83d83bebf401 ("console/fbcon: Add support for deferred console takeover") Cc: Hans de Goede <hdegoede(a)redhat.com> Cc: linux-fbdev(a)vger.kernel.org Cc: dri-devel(a)lists.freedesktop.org Cc: <stable(a)vger.kernel.org> # v4.19+ Link: https://lore.kernel.org/r/20250520071418.8462-1-tzimmermann@suse.de diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c index 139049368fdc..7d02470f19b9 100644 --- a/drivers/video/console/dummycon.c +++ b/drivers/video/console/dummycon.c @@ -85,6 +85,15 @@ static bool dummycon_blank(struct vc_data *vc, enum vesa_blank_mode blank, /* Redraw, so that we get putc(s) for output done while blanked */ return true; } + +static bool dummycon_switch(struct vc_data *vc) +{ + /* + * Redraw, so that we get putc(s) for output done while switched + * away. Informs deferred consoles to take over the display. + */ + return true; +} #else static void dummycon_putc(struct vc_data *vc, u16 c, unsigned int y, unsigned int x) { } @@ -95,6 +104,10 @@ static bool dummycon_blank(struct vc_data *vc, enum vesa_blank_mode blank, { return false; } +static bool dummycon_switch(struct vc_data *vc) +{ + return false; +} #endif static const char *dummycon_startup(void) @@ -124,11 +137,6 @@ static bool dummycon_scroll(struct vc_data *vc, unsigned int top, return false; } -static bool dummycon_switch(struct vc_data *vc) -{ - return false; -} - /* * The console `switch' structure for the dummy console *

2 months, 4 weeks

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FAILED: patch "[PATCH] dummycon: Trigger redraw when switching consoles with" 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 03bcbbb3995ba5df43af9aba45334e35f2dfe27b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062041-wrecking-disgrace-7467@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 03bcbbb3995ba5df43af9aba45334e35f2dfe27b Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann <tzimmermann(a)suse.de> Date: Tue, 20 May 2025 09:14:00 +0200 Subject: [PATCH] dummycon: Trigger redraw when switching consoles with deferred takeover Signal vt subsystem to redraw console when switching to dummycon with deferred takeover enabled. Makes the console switch to fbcon and displays the available output. With deferred takeover enabled, dummycon acts as the placeholder until the first output to the console happens. At that point, fbcon takes over. If the output happens while dummycon is not active, it cannot inform fbcon. This is the case if the vt subsystem runs in graphics mode. A typical graphical boot starts plymouth, a display manager and a compositor; all while leaving out dummycon. Switching to a text-mode console leaves the console with dummycon even if a getty terminal has been started. Returning true from dummycon's con_switch helper signals the vt subsystem to redraw the screen. If there's output available dummycon's con_putc{s} helpers trigger deferred takeover of fbcon, which sets a display mode and displays the output. If no output is available, dummycon remains active. v2: - make the comment slightly more verbose (Javier) Signed-off-by: Thomas Zimmermann <tzimmermann(a)suse.de> Reported-by: Andrei Borzenkov <arvidjaar(a)gmail.com> Closes: https://bugzilla.suse.com/show_bug.cgi?id=1242191 Tested-by: Andrei Borzenkov <arvidjaar(a)gmail.com> Acked-by: Javier Martinez Canillas <javierm(a)redhat.com> Fixes: 83d83bebf401 ("console/fbcon: Add support for deferred console takeover") Cc: Hans de Goede <hdegoede(a)redhat.com> Cc: linux-fbdev(a)vger.kernel.org Cc: dri-devel(a)lists.freedesktop.org Cc: <stable(a)vger.kernel.org> # v4.19+ Link: https://lore.kernel.org/r/20250520071418.8462-1-tzimmermann@suse.de diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c index 139049368fdc..7d02470f19b9 100644 --- a/drivers/video/console/dummycon.c +++ b/drivers/video/console/dummycon.c @@ -85,6 +85,15 @@ static bool dummycon_blank(struct vc_data *vc, enum vesa_blank_mode blank, /* Redraw, so that we get putc(s) for output done while blanked */ return true; } + +static bool dummycon_switch(struct vc_data *vc) +{ + /* + * Redraw, so that we get putc(s) for output done while switched + * away. Informs deferred consoles to take over the display. + */ + return true; +} #else static void dummycon_putc(struct vc_data *vc, u16 c, unsigned int y, unsigned int x) { } @@ -95,6 +104,10 @@ static bool dummycon_blank(struct vc_data *vc, enum vesa_blank_mode blank, { return false; } +static bool dummycon_switch(struct vc_data *vc) +{ + return false; +} #endif static const char *dummycon_startup(void) @@ -124,11 +137,6 @@ static bool dummycon_scroll(struct vc_data *vc, unsigned int top, return false; } -static bool dummycon_switch(struct vc_data *vc) -{ - return false; -} - /* * The console `switch' structure for the dummy console *

2 months, 4 weeks

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FAILED: patch "[PATCH] dummycon: Trigger redraw when switching consoles with" 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 03bcbbb3995ba5df43af9aba45334e35f2dfe27b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062040-scarring-repeal-109f@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 03bcbbb3995ba5df43af9aba45334e35f2dfe27b Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann <tzimmermann(a)suse.de> Date: Tue, 20 May 2025 09:14:00 +0200 Subject: [PATCH] dummycon: Trigger redraw when switching consoles with deferred takeover Signal vt subsystem to redraw console when switching to dummycon with deferred takeover enabled. Makes the console switch to fbcon and displays the available output. With deferred takeover enabled, dummycon acts as the placeholder until the first output to the console happens. At that point, fbcon takes over. If the output happens while dummycon is not active, it cannot inform fbcon. This is the case if the vt subsystem runs in graphics mode. A typical graphical boot starts plymouth, a display manager and a compositor; all while leaving out dummycon. Switching to a text-mode console leaves the console with dummycon even if a getty terminal has been started. Returning true from dummycon's con_switch helper signals the vt subsystem to redraw the screen. If there's output available dummycon's con_putc{s} helpers trigger deferred takeover of fbcon, which sets a display mode and displays the output. If no output is available, dummycon remains active. v2: - make the comment slightly more verbose (Javier) Signed-off-by: Thomas Zimmermann <tzimmermann(a)suse.de> Reported-by: Andrei Borzenkov <arvidjaar(a)gmail.com> Closes: https://bugzilla.suse.com/show_bug.cgi?id=1242191 Tested-by: Andrei Borzenkov <arvidjaar(a)gmail.com> Acked-by: Javier Martinez Canillas <javierm(a)redhat.com> Fixes: 83d83bebf401 ("console/fbcon: Add support for deferred console takeover") Cc: Hans de Goede <hdegoede(a)redhat.com> Cc: linux-fbdev(a)vger.kernel.org Cc: dri-devel(a)lists.freedesktop.org Cc: <stable(a)vger.kernel.org> # v4.19+ Link: https://lore.kernel.org/r/20250520071418.8462-1-tzimmermann@suse.de diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c index 139049368fdc..7d02470f19b9 100644 --- a/drivers/video/console/dummycon.c +++ b/drivers/video/console/dummycon.c @@ -85,6 +85,15 @@ static bool dummycon_blank(struct vc_data *vc, enum vesa_blank_mode blank, /* Redraw, so that we get putc(s) for output done while blanked */ return true; } + +static bool dummycon_switch(struct vc_data *vc) +{ + /* + * Redraw, so that we get putc(s) for output done while switched + * away. Informs deferred consoles to take over the display. + */ + return true; +} #else static void dummycon_putc(struct vc_data *vc, u16 c, unsigned int y, unsigned int x) { } @@ -95,6 +104,10 @@ static bool dummycon_blank(struct vc_data *vc, enum vesa_blank_mode blank, { return false; } +static bool dummycon_switch(struct vc_data *vc) +{ + return false; +} #endif static const char *dummycon_startup(void) @@ -124,11 +137,6 @@ static bool dummycon_scroll(struct vc_data *vc, unsigned int top, return false; } -static bool dummycon_switch(struct vc_data *vc) -{ - return false; -} - /* * The console `switch' structure for the dummy console *

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