February 2023 - Linux-stable-mirror

FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx rearm race" 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>. Possible dependencies: 57e9af7831dc ("serial: 8250_dma: Fix DMA Rx rearm race") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 57e9af7831dcf211c5c689c2a6f209f4abdf0bce Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:41 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx rearm race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As DMA Rx can be completed from two places, it is possible that DMA Rx completes before DMA completion callback had a chance to complete it. Once the previous DMA Rx has been completed, a new one can be started on the next UART interrupt. The following race is possible (uart_unlock_and_check_sysrq_irqrestore() replaced with spin_unlock_irqrestore() for simplicity/clarity): CPU0 CPU1 dma_rx_complete() serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma_flush() __dma_rx_complete() dma->rx_running = 0 // Complete DMA Rx spin_unlock_irqrestore(&port->lock) serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma() dma->rx_running = 1 // Setup a new DMA Rx spin_unlock_irqrestore(&port->lock) spin_lock_irqsave(&port->lock) // sees dma->rx_running = 1 __dma_rx_complete() dma->rx_running = 0 // Incorrectly complete // running DMA Rx This race seems somewhat theoretical to occur for real but handle it correctly regardless. Check what is the DMA status before complething anything in __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-3-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 5594883a96f8..7fa66501792d 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -43,15 +43,23 @@ static void __dma_rx_complete(struct uart_8250_port *p) struct uart_8250_dma *dma = p->dma; struct tty_port *tty_port = &p->port.state->port; struct dma_tx_state state; + enum dma_status dma_status; int count; - dma->rx_running = 0; - dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + /* + * New DMA Rx can be started during the completion handler before it + * could acquire port's lock and it might still be ongoing. Don't to + * anything in such case. + */ + dma_status = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + if (dma_status == DMA_IN_PROGRESS) + return; count = dma->rx_size - state.residue; tty_insert_flip_string(tty_port, dma->rx_buf, count); p->port.icount.rx += count; + dma->rx_running = 0; tty_flip_buffer_push(tty_port); }

1 year, 10 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx rearm race" 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>. Possible dependencies: 57e9af7831dc ("serial: 8250_dma: Fix DMA Rx rearm race") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 57e9af7831dcf211c5c689c2a6f209f4abdf0bce Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:41 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx rearm race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As DMA Rx can be completed from two places, it is possible that DMA Rx completes before DMA completion callback had a chance to complete it. Once the previous DMA Rx has been completed, a new one can be started on the next UART interrupt. The following race is possible (uart_unlock_and_check_sysrq_irqrestore() replaced with spin_unlock_irqrestore() for simplicity/clarity): CPU0 CPU1 dma_rx_complete() serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma_flush() __dma_rx_complete() dma->rx_running = 0 // Complete DMA Rx spin_unlock_irqrestore(&port->lock) serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma() dma->rx_running = 1 // Setup a new DMA Rx spin_unlock_irqrestore(&port->lock) spin_lock_irqsave(&port->lock) // sees dma->rx_running = 1 __dma_rx_complete() dma->rx_running = 0 // Incorrectly complete // running DMA Rx This race seems somewhat theoretical to occur for real but handle it correctly regardless. Check what is the DMA status before complething anything in __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-3-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 5594883a96f8..7fa66501792d 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -43,15 +43,23 @@ static void __dma_rx_complete(struct uart_8250_port *p) struct uart_8250_dma *dma = p->dma; struct tty_port *tty_port = &p->port.state->port; struct dma_tx_state state; + enum dma_status dma_status; int count; - dma->rx_running = 0; - dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + /* + * New DMA Rx can be started during the completion handler before it + * could acquire port's lock and it might still be ongoing. Don't to + * anything in such case. + */ + dma_status = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + if (dma_status == DMA_IN_PROGRESS) + return; count = dma->rx_size - state.residue; tty_insert_flip_string(tty_port, dma->rx_buf, count); p->port.icount.rx += count; + dma->rx_running = 0; tty_flip_buffer_push(tty_port); }

1 year, 10 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx rearm race" failed to apply to all-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the all-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>. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 57e9af7831dcf211c5c689c2a6f209f4abdf0bce Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:41 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx rearm race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As DMA Rx can be completed from two places, it is possible that DMA Rx completes before DMA completion callback had a chance to complete it. Once the previous DMA Rx has been completed, a new one can be started on the next UART interrupt. The following race is possible (uart_unlock_and_check_sysrq_irqrestore() replaced with spin_unlock_irqrestore() for simplicity/clarity): CPU0 CPU1 dma_rx_complete() serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma_flush() __dma_rx_complete() dma->rx_running = 0 // Complete DMA Rx spin_unlock_irqrestore(&port->lock) serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma() dma->rx_running = 1 // Setup a new DMA Rx spin_unlock_irqrestore(&port->lock) spin_lock_irqsave(&port->lock) // sees dma->rx_running = 1 __dma_rx_complete() dma->rx_running = 0 // Incorrectly complete // running DMA Rx This race seems somewhat theoretical to occur for real but handle it correctly regardless. Check what is the DMA status before complething anything in __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-3-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 5594883a96f8..7fa66501792d 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -43,15 +43,23 @@ static void __dma_rx_complete(struct uart_8250_port *p) struct uart_8250_dma *dma = p->dma; struct tty_port *tty_port = &p->port.state->port; struct dma_tx_state state; + enum dma_status dma_status; int count; - dma->rx_running = 0; - dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + /* + * New DMA Rx can be started during the completion handler before it + * could acquire port's lock and it might still be ongoing. Don't to + * anything in such case. + */ + dma_status = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + if (dma_status == DMA_IN_PROGRESS) + return; count = dma->rx_size - state.residue; tty_insert_flip_string(tty_port, dma->rx_buf, count); p->port.icount.rx += count; + dma->rx_running = 0; tty_flip_buffer_push(tty_port); }

1 year, 10 months

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FAILED: patch "[PATCH] migrate: hugetlb: check for hugetlb shared PMD in node" 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>. Possible dependencies: 73bdf65ea748 ("migrate: hugetlb: check for hugetlb shared PMD in node migration") 7ce82f4c3f3e ("mm/migration: return errno when isolate_huge_page failed") 1b7f7e58decc ("mm/gup: Convert check_and_migrate_movable_pages() to use a folio") f9f38f78c5d5 ("mm: refactor check_and_migrate_movable_pages") 5ac95884a784 ("mm/migrate: enable returning precise migrate_pages() success count") c5b5a3dd2c1f ("mm: thp: refactor NUMA fault handling") 5db4f15c4fd7 ("mm: memory: add orig_pmd to struct vm_fault") 8f34f1eac382 ("mm/userfaultfd: fix uffd-wp special cases for fork()") 25182f05ffed ("mm,hwpoison: fix race with hugetlb page allocation") f68749ec342b ("mm/gup: longterm pin migration cleanup") d1e153fea2a8 ("mm/gup: migrate pinned pages out of movable zone") 1a08ae36cf8b ("mm cma: rename PF_MEMALLOC_NOCMA to PF_MEMALLOC_PIN") 6e7f34ebb8d2 ("mm/gup: check for isolation errors") f0f4463837da ("mm/gup: return an error on migration failure") 83c02c23d074 ("mm/gup: check every subpage of a compound page during isolation") c991ffef7bce ("mm/gup: don't pin migrated cma pages in movable zone") 7ee820ee7238 ("Revert "mm: migrate: skip shared exec THP for NUMA balancing"") ae37c7ff79f1 ("mm: make alloc_contig_range handle in-use hugetlb pages") 369fa227c219 ("mm: make alloc_contig_range handle free hugetlb pages") c2ad7a1ffeaf ("mm,compaction: let isolate_migratepages_{range,block} return error codes") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 73bdf65ea74857d7fb2ec3067a3cec0e261b1462 Mon Sep 17 00:00:00 2001 From: Mike Kravetz <mike.kravetz(a)oracle.com> Date: Thu, 26 Jan 2023 14:27:21 -0800 Subject: [PATCH] migrate: hugetlb: check for hugetlb shared PMD in node migration migrate_pages/mempolicy semantics state that CAP_SYS_NICE is required to move pages shared with another process to a different node. page_mapcount > 1 is being used to determine if a hugetlb page is shared. However, a hugetlb page will have a mapcount of 1 if mapped by multiple processes via a shared PMD. As a result, hugetlb pages shared by multiple processes and mapped with a shared PMD can be moved by a process without CAP_SYS_NICE. To fix, check for a shared PMD if mapcount is 1. If a shared PMD is found consider the page shared. Link: https://lkml.kernel.org/r/20230126222721.222195-3-mike.kravetz@oracle.com Fixes: e2d8cf405525 ("migrate: add hugepage migration code to migrate_pages()") Signed-off-by: Mike Kravetz <mike.kravetz(a)oracle.com> Acked-by: Peter Xu <peterx(a)redhat.com> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: James Houghton <jthoughton(a)google.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: Michal Hocko <mhocko(a)suse.com> Cc: Muchun Song <songmuchun(a)bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi(a)linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola(a)gmail.com> Cc: Yang Shi <shy828301(a)gmail.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 02c8a712282f..f940395667c8 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -600,7 +600,8 @@ static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask, /* With MPOL_MF_MOVE, we migrate only unshared hugepage. */ if (flags & (MPOL_MF_MOVE_ALL) || - (flags & MPOL_MF_MOVE && page_mapcount(page) == 1)) { + (flags & MPOL_MF_MOVE && page_mapcount(page) == 1 && + !hugetlb_pmd_shared(pte))) { if (isolate_hugetlb(page, qp->pagelist) && (flags & MPOL_MF_STRICT)) /*

1 year, 10 months

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FAILED: patch "[PATCH] migrate: hugetlb: check for hugetlb shared PMD in node" 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>. Possible dependencies: 73bdf65ea748 ("migrate: hugetlb: check for hugetlb shared PMD in node migration") 7ce82f4c3f3e ("mm/migration: return errno when isolate_huge_page failed") 1b7f7e58decc ("mm/gup: Convert check_and_migrate_movable_pages() to use a folio") f9f38f78c5d5 ("mm: refactor check_and_migrate_movable_pages") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 73bdf65ea74857d7fb2ec3067a3cec0e261b1462 Mon Sep 17 00:00:00 2001 From: Mike Kravetz <mike.kravetz(a)oracle.com> Date: Thu, 26 Jan 2023 14:27:21 -0800 Subject: [PATCH] migrate: hugetlb: check for hugetlb shared PMD in node migration migrate_pages/mempolicy semantics state that CAP_SYS_NICE is required to move pages shared with another process to a different node. page_mapcount > 1 is being used to determine if a hugetlb page is shared. However, a hugetlb page will have a mapcount of 1 if mapped by multiple processes via a shared PMD. As a result, hugetlb pages shared by multiple processes and mapped with a shared PMD can be moved by a process without CAP_SYS_NICE. To fix, check for a shared PMD if mapcount is 1. If a shared PMD is found consider the page shared. Link: https://lkml.kernel.org/r/20230126222721.222195-3-mike.kravetz@oracle.com Fixes: e2d8cf405525 ("migrate: add hugepage migration code to migrate_pages()") Signed-off-by: Mike Kravetz <mike.kravetz(a)oracle.com> Acked-by: Peter Xu <peterx(a)redhat.com> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: James Houghton <jthoughton(a)google.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: Michal Hocko <mhocko(a)suse.com> Cc: Muchun Song <songmuchun(a)bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi(a)linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola(a)gmail.com> Cc: Yang Shi <shy828301(a)gmail.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 02c8a712282f..f940395667c8 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -600,7 +600,8 @@ static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask, /* With MPOL_MF_MOVE, we migrate only unshared hugepage. */ if (flags & (MPOL_MF_MOVE_ALL) || - (flags & MPOL_MF_MOVE && page_mapcount(page) == 1)) { + (flags & MPOL_MF_MOVE && page_mapcount(page) == 1 && + !hugetlb_pmd_shared(pte))) { if (isolate_hugetlb(page, qp->pagelist) && (flags & MPOL_MF_STRICT)) /*

1 year, 10 months

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FAILED: patch "[PATCH] mm/khugepaged: fix ->anon_vma race" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 023f47a8250c ("mm/khugepaged: fix ->anon_vma race") 34488399fa08 ("mm/madvise: add file and shmem support to MADV_COLLAPSE") 58ac9a8993a1 ("mm/khugepaged: attempt to map file/shmem-backed pte-mapped THPs by pmds") 780a4b6fb865 ("mm/khugepaged: check compound_order() in collapse_pte_mapped_thp()") b26e27015ec9 ("mm: thp: convert to use common struct mm_slot") 685405020b9f ("mm/khugepaged: stop using vma linked list") 7d2c4385c341 ("mm/khugepaged: rename prefix of shared collapse functions") 7d8faaf15545 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse") 507228044236 ("mm/khugepaged: record SCAN_PMD_MAPPED when scan_pmd() finds hugepage") a7f4e6e4c47c ("mm/thp: add flag to enforce sysfs THP in hugepage_vma_check()") 50ad2f24b3b4 ("mm/khugepaged: propagate enum scan_result codes back to callers") 9710a78ab2ae ("mm/khugepaged: dedup and simplify hugepage alloc and charging") 34d6b470ab9c ("mm/khugepaged: add struct collapse_control") c6a7f445a272 ("mm: khugepaged: don't carry huge page to the next loop for !CONFIG_NUMA") 1064026bab9f ("mm: khugepaged: reorg some khugepaged helpers") 7da4e2cb8b1f ("mm: thp: kill __transhuge_page_enabled()") 9fec51689ff6 ("mm: thp: kill transparent_hugepage_active()") f707fa493784 ("mm: khugepaged: better comments for anon vma check in hugepage_vma_revalidate") 4fa6893faeaa ("mm: thp: consolidate vma size check to transhuge_vma_suitable") 66137fb34a4b ("mm: khugepaged: check THP flag in hugepage_vma_check()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 023f47a8250c6bdb4aebe744db4bf7f73414028b Mon Sep 17 00:00:00 2001 From: Jann Horn <jannh(a)google.com> Date: Wed, 11 Jan 2023 14:33:51 +0100 Subject: [PATCH] mm/khugepaged: fix ->anon_vma race If an ->anon_vma is attached to the VMA, collapse_and_free_pmd() requires it to be locked. Page table traversal is allowed under any one of the mmap lock, the anon_vma lock (if the VMA is associated with an anon_vma), and the mapping lock (if the VMA is associated with a mapping); and so to be able to remove page tables, we must hold all three of them. retract_page_tables() bails out if an ->anon_vma is attached, but does this check before holding the mmap lock (as the comment above the check explains). If we racily merged an existing ->anon_vma (shared with a child process) from a neighboring VMA, subsequent rmap traversals on pages belonging to the child will be able to see the page tables that we are concurrently removing while assuming that nothing else can access them. Repeat the ->anon_vma check once we hold the mmap lock to ensure that there really is no concurrent page table access. Hitting this bug causes a lockdep warning in collapse_and_free_pmd(), in the line "lockdep_assert_held_write(&vma->anon_vma->root->rwsem)". It can also lead to use-after-free access. Link: https://lore.kernel.org/linux-mm/CAG48ez3434wZBKFFbdx4M9j6eUwSUVPd4dxhzW_k_… Link: https://lkml.kernel.org/r/20230111133351.807024-1-jannh@google.com Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by: Jann Horn <jannh(a)google.com> Reported-by: Zach O'Keefe <zokeefe(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)intel.linux.com> Reviewed-by: Yang Shi <shy828301(a)gmail.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 79be13133322..935aa8b71d1c 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1642,7 +1642,7 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, * has higher cost too. It would also probably require locking * the anon_vma. */ - if (vma->anon_vma) { + if (READ_ONCE(vma->anon_vma)) { result = SCAN_PAGE_ANON; goto next; } @@ -1670,6 +1670,18 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, result = SCAN_PTE_MAPPED_HUGEPAGE; if ((cc->is_khugepaged || is_target) && mmap_write_trylock(mm)) { + /* + * Re-check whether we have an ->anon_vma, because + * collapse_and_free_pmd() requires that either no + * ->anon_vma exists or the anon_vma is locked. + * We already checked ->anon_vma above, but that check + * is racy because ->anon_vma can be populated under the + * mmap lock in read mode. + */ + if (vma->anon_vma) { + result = SCAN_PAGE_ANON; + goto unlock_next; + } /* * When a vma is registered with uffd-wp, we can't * recycle the pmd pgtable because there can be pte

1 year, 10 months

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FAILED: patch "[PATCH] mm/khugepaged: fix ->anon_vma race" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-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>. Possible dependencies: 023f47a8250c ("mm/khugepaged: fix ->anon_vma race") 34488399fa08 ("mm/madvise: add file and shmem support to MADV_COLLAPSE") 58ac9a8993a1 ("mm/khugepaged: attempt to map file/shmem-backed pte-mapped THPs by pmds") 780a4b6fb865 ("mm/khugepaged: check compound_order() in collapse_pte_mapped_thp()") b26e27015ec9 ("mm: thp: convert to use common struct mm_slot") 685405020b9f ("mm/khugepaged: stop using vma linked list") 7d2c4385c341 ("mm/khugepaged: rename prefix of shared collapse functions") 7d8faaf15545 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse") 507228044236 ("mm/khugepaged: record SCAN_PMD_MAPPED when scan_pmd() finds hugepage") a7f4e6e4c47c ("mm/thp: add flag to enforce sysfs THP in hugepage_vma_check()") 50ad2f24b3b4 ("mm/khugepaged: propagate enum scan_result codes back to callers") 9710a78ab2ae ("mm/khugepaged: dedup and simplify hugepage alloc and charging") 34d6b470ab9c ("mm/khugepaged: add struct collapse_control") c6a7f445a272 ("mm: khugepaged: don't carry huge page to the next loop for !CONFIG_NUMA") 1064026bab9f ("mm: khugepaged: reorg some khugepaged helpers") 7da4e2cb8b1f ("mm: thp: kill __transhuge_page_enabled()") 9fec51689ff6 ("mm: thp: kill transparent_hugepage_active()") f707fa493784 ("mm: khugepaged: better comments for anon vma check in hugepage_vma_revalidate") 4fa6893faeaa ("mm: thp: consolidate vma size check to transhuge_vma_suitable") 66137fb34a4b ("mm: khugepaged: check THP flag in hugepage_vma_check()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 023f47a8250c6bdb4aebe744db4bf7f73414028b Mon Sep 17 00:00:00 2001 From: Jann Horn <jannh(a)google.com> Date: Wed, 11 Jan 2023 14:33:51 +0100 Subject: [PATCH] mm/khugepaged: fix ->anon_vma race If an ->anon_vma is attached to the VMA, collapse_and_free_pmd() requires it to be locked. Page table traversal is allowed under any one of the mmap lock, the anon_vma lock (if the VMA is associated with an anon_vma), and the mapping lock (if the VMA is associated with a mapping); and so to be able to remove page tables, we must hold all three of them. retract_page_tables() bails out if an ->anon_vma is attached, but does this check before holding the mmap lock (as the comment above the check explains). If we racily merged an existing ->anon_vma (shared with a child process) from a neighboring VMA, subsequent rmap traversals on pages belonging to the child will be able to see the page tables that we are concurrently removing while assuming that nothing else can access them. Repeat the ->anon_vma check once we hold the mmap lock to ensure that there really is no concurrent page table access. Hitting this bug causes a lockdep warning in collapse_and_free_pmd(), in the line "lockdep_assert_held_write(&vma->anon_vma->root->rwsem)". It can also lead to use-after-free access. Link: https://lore.kernel.org/linux-mm/CAG48ez3434wZBKFFbdx4M9j6eUwSUVPd4dxhzW_k_… Link: https://lkml.kernel.org/r/20230111133351.807024-1-jannh@google.com Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by: Jann Horn <jannh(a)google.com> Reported-by: Zach O'Keefe <zokeefe(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)intel.linux.com> Reviewed-by: Yang Shi <shy828301(a)gmail.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 79be13133322..935aa8b71d1c 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1642,7 +1642,7 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, * has higher cost too. It would also probably require locking * the anon_vma. */ - if (vma->anon_vma) { + if (READ_ONCE(vma->anon_vma)) { result = SCAN_PAGE_ANON; goto next; } @@ -1670,6 +1670,18 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, result = SCAN_PTE_MAPPED_HUGEPAGE; if ((cc->is_khugepaged || is_target) && mmap_write_trylock(mm)) { + /* + * Re-check whether we have an ->anon_vma, because + * collapse_and_free_pmd() requires that either no + * ->anon_vma exists or the anon_vma is locked. + * We already checked ->anon_vma above, but that check + * is racy because ->anon_vma can be populated under the + * mmap lock in read mode. + */ + if (vma->anon_vma) { + result = SCAN_PAGE_ANON; + goto unlock_next; + } /* * When a vma is registered with uffd-wp, we can't * recycle the pmd pgtable because there can be pte

1 year, 10 months

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FAILED: patch "[PATCH] mm/khugepaged: fix ->anon_vma race" 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>. Possible dependencies: 023f47a8250c ("mm/khugepaged: fix ->anon_vma race") 34488399fa08 ("mm/madvise: add file and shmem support to MADV_COLLAPSE") 58ac9a8993a1 ("mm/khugepaged: attempt to map file/shmem-backed pte-mapped THPs by pmds") 780a4b6fb865 ("mm/khugepaged: check compound_order() in collapse_pte_mapped_thp()") b26e27015ec9 ("mm: thp: convert to use common struct mm_slot") 685405020b9f ("mm/khugepaged: stop using vma linked list") 7d2c4385c341 ("mm/khugepaged: rename prefix of shared collapse functions") 7d8faaf15545 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse") 507228044236 ("mm/khugepaged: record SCAN_PMD_MAPPED when scan_pmd() finds hugepage") a7f4e6e4c47c ("mm/thp: add flag to enforce sysfs THP in hugepage_vma_check()") 50ad2f24b3b4 ("mm/khugepaged: propagate enum scan_result codes back to callers") 9710a78ab2ae ("mm/khugepaged: dedup and simplify hugepage alloc and charging") 34d6b470ab9c ("mm/khugepaged: add struct collapse_control") c6a7f445a272 ("mm: khugepaged: don't carry huge page to the next loop for !CONFIG_NUMA") 1064026bab9f ("mm: khugepaged: reorg some khugepaged helpers") 7da4e2cb8b1f ("mm: thp: kill __transhuge_page_enabled()") 9fec51689ff6 ("mm: thp: kill transparent_hugepage_active()") f707fa493784 ("mm: khugepaged: better comments for anon vma check in hugepage_vma_revalidate") 4fa6893faeaa ("mm: thp: consolidate vma size check to transhuge_vma_suitable") 66137fb34a4b ("mm: khugepaged: check THP flag in hugepage_vma_check()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 023f47a8250c6bdb4aebe744db4bf7f73414028b Mon Sep 17 00:00:00 2001 From: Jann Horn <jannh(a)google.com> Date: Wed, 11 Jan 2023 14:33:51 +0100 Subject: [PATCH] mm/khugepaged: fix ->anon_vma race If an ->anon_vma is attached to the VMA, collapse_and_free_pmd() requires it to be locked. Page table traversal is allowed under any one of the mmap lock, the anon_vma lock (if the VMA is associated with an anon_vma), and the mapping lock (if the VMA is associated with a mapping); and so to be able to remove page tables, we must hold all three of them. retract_page_tables() bails out if an ->anon_vma is attached, but does this check before holding the mmap lock (as the comment above the check explains). If we racily merged an existing ->anon_vma (shared with a child process) from a neighboring VMA, subsequent rmap traversals on pages belonging to the child will be able to see the page tables that we are concurrently removing while assuming that nothing else can access them. Repeat the ->anon_vma check once we hold the mmap lock to ensure that there really is no concurrent page table access. Hitting this bug causes a lockdep warning in collapse_and_free_pmd(), in the line "lockdep_assert_held_write(&vma->anon_vma->root->rwsem)". It can also lead to use-after-free access. Link: https://lore.kernel.org/linux-mm/CAG48ez3434wZBKFFbdx4M9j6eUwSUVPd4dxhzW_k_… Link: https://lkml.kernel.org/r/20230111133351.807024-1-jannh@google.com Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by: Jann Horn <jannh(a)google.com> Reported-by: Zach O'Keefe <zokeefe(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)intel.linux.com> Reviewed-by: Yang Shi <shy828301(a)gmail.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 79be13133322..935aa8b71d1c 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1642,7 +1642,7 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, * has higher cost too. It would also probably require locking * the anon_vma. */ - if (vma->anon_vma) { + if (READ_ONCE(vma->anon_vma)) { result = SCAN_PAGE_ANON; goto next; } @@ -1670,6 +1670,18 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, result = SCAN_PTE_MAPPED_HUGEPAGE; if ((cc->is_khugepaged || is_target) && mmap_write_trylock(mm)) { + /* + * Re-check whether we have an ->anon_vma, because + * collapse_and_free_pmd() requires that either no + * ->anon_vma exists or the anon_vma is locked. + * We already checked ->anon_vma above, but that check + * is racy because ->anon_vma can be populated under the + * mmap lock in read mode. + */ + if (vma->anon_vma) { + result = SCAN_PAGE_ANON; + goto unlock_next; + } /* * When a vma is registered with uffd-wp, we can't * recycle the pmd pgtable because there can be pte

1 year, 10 months

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FAILED: patch "[PATCH] mm/khugepaged: fix ->anon_vma race" 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>. Possible dependencies: 023f47a8250c ("mm/khugepaged: fix ->anon_vma race") 34488399fa08 ("mm/madvise: add file and shmem support to MADV_COLLAPSE") 58ac9a8993a1 ("mm/khugepaged: attempt to map file/shmem-backed pte-mapped THPs by pmds") 780a4b6fb865 ("mm/khugepaged: check compound_order() in collapse_pte_mapped_thp()") b26e27015ec9 ("mm: thp: convert to use common struct mm_slot") 685405020b9f ("mm/khugepaged: stop using vma linked list") 7d2c4385c341 ("mm/khugepaged: rename prefix of shared collapse functions") 7d8faaf15545 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse") 507228044236 ("mm/khugepaged: record SCAN_PMD_MAPPED when scan_pmd() finds hugepage") a7f4e6e4c47c ("mm/thp: add flag to enforce sysfs THP in hugepage_vma_check()") 50ad2f24b3b4 ("mm/khugepaged: propagate enum scan_result codes back to callers") 9710a78ab2ae ("mm/khugepaged: dedup and simplify hugepage alloc and charging") 34d6b470ab9c ("mm/khugepaged: add struct collapse_control") c6a7f445a272 ("mm: khugepaged: don't carry huge page to the next loop for !CONFIG_NUMA") 1064026bab9f ("mm: khugepaged: reorg some khugepaged helpers") 7da4e2cb8b1f ("mm: thp: kill __transhuge_page_enabled()") 9fec51689ff6 ("mm: thp: kill transparent_hugepage_active()") f707fa493784 ("mm: khugepaged: better comments for anon vma check in hugepage_vma_revalidate") 4fa6893faeaa ("mm: thp: consolidate vma size check to transhuge_vma_suitable") 66137fb34a4b ("mm: khugepaged: check THP flag in hugepage_vma_check()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 023f47a8250c6bdb4aebe744db4bf7f73414028b Mon Sep 17 00:00:00 2001 From: Jann Horn <jannh(a)google.com> Date: Wed, 11 Jan 2023 14:33:51 +0100 Subject: [PATCH] mm/khugepaged: fix ->anon_vma race If an ->anon_vma is attached to the VMA, collapse_and_free_pmd() requires it to be locked. Page table traversal is allowed under any one of the mmap lock, the anon_vma lock (if the VMA is associated with an anon_vma), and the mapping lock (if the VMA is associated with a mapping); and so to be able to remove page tables, we must hold all three of them. retract_page_tables() bails out if an ->anon_vma is attached, but does this check before holding the mmap lock (as the comment above the check explains). If we racily merged an existing ->anon_vma (shared with a child process) from a neighboring VMA, subsequent rmap traversals on pages belonging to the child will be able to see the page tables that we are concurrently removing while assuming that nothing else can access them. Repeat the ->anon_vma check once we hold the mmap lock to ensure that there really is no concurrent page table access. Hitting this bug causes a lockdep warning in collapse_and_free_pmd(), in the line "lockdep_assert_held_write(&vma->anon_vma->root->rwsem)". It can also lead to use-after-free access. Link: https://lore.kernel.org/linux-mm/CAG48ez3434wZBKFFbdx4M9j6eUwSUVPd4dxhzW_k_… Link: https://lkml.kernel.org/r/20230111133351.807024-1-jannh@google.com Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by: Jann Horn <jannh(a)google.com> Reported-by: Zach O'Keefe <zokeefe(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)intel.linux.com> Reviewed-by: Yang Shi <shy828301(a)gmail.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 79be13133322..935aa8b71d1c 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1642,7 +1642,7 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, * has higher cost too. It would also probably require locking * the anon_vma. */ - if (vma->anon_vma) { + if (READ_ONCE(vma->anon_vma)) { result = SCAN_PAGE_ANON; goto next; } @@ -1670,6 +1670,18 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, result = SCAN_PTE_MAPPED_HUGEPAGE; if ((cc->is_khugepaged || is_target) && mmap_write_trylock(mm)) { + /* + * Re-check whether we have an ->anon_vma, because + * collapse_and_free_pmd() requires that either no + * ->anon_vma exists or the anon_vma is locked. + * We already checked ->anon_vma above, but that check + * is racy because ->anon_vma can be populated under the + * mmap lock in read mode. + */ + if (vma->anon_vma) { + result = SCAN_PAGE_ANON; + goto unlock_next; + } /* * When a vma is registered with uffd-wp, we can't * recycle the pmd pgtable because there can be pte

1 year, 10 months

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FAILED: patch "[PATCH] mm/khugepaged: fix ->anon_vma race" 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>. Possible dependencies: 023f47a8250c ("mm/khugepaged: fix ->anon_vma race") 34488399fa08 ("mm/madvise: add file and shmem support to MADV_COLLAPSE") 58ac9a8993a1 ("mm/khugepaged: attempt to map file/shmem-backed pte-mapped THPs by pmds") 780a4b6fb865 ("mm/khugepaged: check compound_order() in collapse_pte_mapped_thp()") b26e27015ec9 ("mm: thp: convert to use common struct mm_slot") 685405020b9f ("mm/khugepaged: stop using vma linked list") 7d2c4385c341 ("mm/khugepaged: rename prefix of shared collapse functions") 7d8faaf15545 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse") 507228044236 ("mm/khugepaged: record SCAN_PMD_MAPPED when scan_pmd() finds hugepage") a7f4e6e4c47c ("mm/thp: add flag to enforce sysfs THP in hugepage_vma_check()") 50ad2f24b3b4 ("mm/khugepaged: propagate enum scan_result codes back to callers") 9710a78ab2ae ("mm/khugepaged: dedup and simplify hugepage alloc and charging") 34d6b470ab9c ("mm/khugepaged: add struct collapse_control") c6a7f445a272 ("mm: khugepaged: don't carry huge page to the next loop for !CONFIG_NUMA") 1064026bab9f ("mm: khugepaged: reorg some khugepaged helpers") 7da4e2cb8b1f ("mm: thp: kill __transhuge_page_enabled()") 9fec51689ff6 ("mm: thp: kill transparent_hugepage_active()") f707fa493784 ("mm: khugepaged: better comments for anon vma check in hugepage_vma_revalidate") 4fa6893faeaa ("mm: thp: consolidate vma size check to transhuge_vma_suitable") 66137fb34a4b ("mm: khugepaged: check THP flag in hugepage_vma_check()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 023f47a8250c6bdb4aebe744db4bf7f73414028b Mon Sep 17 00:00:00 2001 From: Jann Horn <jannh(a)google.com> Date: Wed, 11 Jan 2023 14:33:51 +0100 Subject: [PATCH] mm/khugepaged: fix ->anon_vma race If an ->anon_vma is attached to the VMA, collapse_and_free_pmd() requires it to be locked. Page table traversal is allowed under any one of the mmap lock, the anon_vma lock (if the VMA is associated with an anon_vma), and the mapping lock (if the VMA is associated with a mapping); and so to be able to remove page tables, we must hold all three of them. retract_page_tables() bails out if an ->anon_vma is attached, but does this check before holding the mmap lock (as the comment above the check explains). If we racily merged an existing ->anon_vma (shared with a child process) from a neighboring VMA, subsequent rmap traversals on pages belonging to the child will be able to see the page tables that we are concurrently removing while assuming that nothing else can access them. Repeat the ->anon_vma check once we hold the mmap lock to ensure that there really is no concurrent page table access. Hitting this bug causes a lockdep warning in collapse_and_free_pmd(), in the line "lockdep_assert_held_write(&vma->anon_vma->root->rwsem)". It can also lead to use-after-free access. Link: https://lore.kernel.org/linux-mm/CAG48ez3434wZBKFFbdx4M9j6eUwSUVPd4dxhzW_k_… Link: https://lkml.kernel.org/r/20230111133351.807024-1-jannh@google.com Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by: Jann Horn <jannh(a)google.com> Reported-by: Zach O'Keefe <zokeefe(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)intel.linux.com> Reviewed-by: Yang Shi <shy828301(a)gmail.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 79be13133322..935aa8b71d1c 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1642,7 +1642,7 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, * has higher cost too. It would also probably require locking * the anon_vma. */ - if (vma->anon_vma) { + if (READ_ONCE(vma->anon_vma)) { result = SCAN_PAGE_ANON; goto next; } @@ -1670,6 +1670,18 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, result = SCAN_PTE_MAPPED_HUGEPAGE; if ((cc->is_khugepaged || is_target) && mmap_write_trylock(mm)) { + /* + * Re-check whether we have an ->anon_vma, because + * collapse_and_free_pmd() requires that either no + * ->anon_vma exists or the anon_vma is locked. + * We already checked ->anon_vma above, but that check + * is racy because ->anon_vma can be populated under the + * mmap lock in read mode. + */ + if (vma->anon_vma) { + result = SCAN_PAGE_ANON; + goto unlock_next; + } /* * When a vma is registered with uffd-wp, we can't * recycle the pmd pgtable because there can be pte

1 year, 10 months

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