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FAILED: patch "[PATCH] mm: userfaultfd: fix race of userfaultfd_move and swap cache" 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 0ea148a799198518d8ebab63ddd0bb6114a103bc # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025063052-strive-fabulous-239b@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 0ea148a799198518d8ebab63ddd0bb6114a103bc Mon Sep 17 00:00:00 2001 From: Kairui Song <kasong(a)tencent.com> Date: Wed, 4 Jun 2025 23:10:38 +0800 Subject: [PATCH] mm: userfaultfd: fix race of userfaultfd_move and swap cache This commit fixes two kinds of races, they may have different results: Barry reported a BUG_ON in commit c50f8e6053b0, we may see the same BUG_ON if the filemap lookup returned NULL and folio is added to swap cache after that. If another kind of race is triggered (folio changed after lookup) we may see RSS counter is corrupted: [ 406.893936] BUG: Bad rss-counter state mm:ffff0000c5a9ddc0 type:MM_ANONPAGES val:-1 [ 406.894071] BUG: Bad rss-counter state mm:ffff0000c5a9ddc0 type:MM_SHMEMPAGES val:1 Because the folio is being accounted to the wrong VMA. I'm not sure if there will be any data corruption though, seems no. The issues above are critical already. On seeing a swap entry PTE, userfaultfd_move does a lockless swap cache lookup, and tries to move the found folio to the faulting vma. Currently, it relies on checking the PTE value to ensure that the moved folio still belongs to the src swap entry and that no new folio has been added to the swap cache, which turns out to be unreliable. While working and reviewing the swap table series with Barry, following existing races are observed and reproduced [1]: In the example below, move_pages_pte is moving src_pte to dst_pte, where src_pte is a swap entry PTE holding swap entry S1, and S1 is not in the swap cache: CPU1 CPU2 userfaultfd_move move_pages_pte() entry = pte_to_swp_entry(orig_src_pte); // Here it got entry = S1 ... < interrupted> ... <swapin src_pte, alloc and use folio A> // folio A is a new allocated folio // and get installed into src_pte <frees swap entry S1> // src_pte now points to folio A, S1 // has swap count == 0, it can be freed // by folio_swap_swap or swap // allocator's reclaim. <try to swap out another folio B> // folio B is a folio in another VMA. <put folio B to swap cache using S1 > // S1 is freed, folio B can use it // for swap out with no problem. ... folio = filemap_get_folio(S1) // Got folio B here !!! ... < interrupted again> ... <swapin folio B and free S1> // Now S1 is free to be used again. <swapout src_pte & folio A using S1> // Now src_pte is a swap entry PTE // holding S1 again. folio_trylock(folio) move_swap_pte double_pt_lock is_pte_pages_stable // Check passed because src_pte == S1 folio_move_anon_rmap(...) // Moved invalid folio B here !!! The race window is very short and requires multiple collisions of multiple rare events, so it's very unlikely to happen, but with a deliberately constructed reproducer and increased time window, it can be reproduced easily. This can be fixed by checking if the folio returned by filemap is the valid swap cache folio after acquiring the folio lock. Another similar race is possible: filemap_get_folio may return NULL, but folio (A) could be swapped in and then swapped out again using the same swap entry after the lookup. In such a case, folio (A) may remain in the swap cache, so it must be moved too: CPU1 CPU2 userfaultfd_move move_pages_pte() entry = pte_to_swp_entry(orig_src_pte); // Here it got entry = S1, and S1 is not in swap cache folio = filemap_get_folio(S1) // Got NULL ... < interrupted again> ... <swapin folio A and free S1> <swapout folio A re-using S1> move_swap_pte double_pt_lock is_pte_pages_stable // Check passed because src_pte == S1 folio_move_anon_rmap(...) // folio A is ignored !!! Fix this by checking the swap cache again after acquiring the src_pte lock. And to avoid the filemap overhead, we check swap_map directly [2]. The SWP_SYNCHRONOUS_IO path does make the problem more complex, but so far we don't need to worry about that, since folios can only be exposed to the swap cache in the swap out path, and this is covered in this patch by checking the swap cache again after acquiring the src_pte lock. Testing with a simple C program that allocates and moves several GB of memory did not show any observable performance change. Link: https://lkml.kernel.org/r/20250604151038.21968-1-ryncsn@gmail.com Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI") Signed-off-by: Kairui Song <kasong(a)tencent.com> Closes: https://lore.kernel.org/linux-mm/CAMgjq7B1K=6OOrK2OUZ0-tqCzi+EJt+2_K97TPGoS… [1] Link: https://lore.kernel.org/all/CAGsJ_4yJhJBo16XhiC-nUzSheyX-V3-nFE+tAi=8Y560K8… [2] Reviewed-by: Lokesh Gidra <lokeshgidra(a)google.com> Acked-by: Peter Xu <peterx(a)redhat.com> Reviewed-by: Suren Baghdasaryan <surenb(a)google.com> Reviewed-by: Barry Song <baohua(a)kernel.org> Reviewed-by: Chris Li <chrisl(a)kernel.org> Cc: Andrea Arcangeli <aarcange(a)redhat.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Kairui Song <kasong(a)tencent.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index bc473ad21202..8253978ee0fb 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -1084,8 +1084,18 @@ static int move_swap_pte(struct mm_struct *mm, struct vm_area_struct *dst_vma, pte_t orig_dst_pte, pte_t orig_src_pte, pmd_t *dst_pmd, pmd_t dst_pmdval, spinlock_t *dst_ptl, spinlock_t *src_ptl, - struct folio *src_folio) + struct folio *src_folio, + struct swap_info_struct *si, swp_entry_t entry) { + /* + * Check if the folio still belongs to the target swap entry after + * acquiring the lock. Folio can be freed in the swap cache while + * not locked. + */ + if (src_folio && unlikely(!folio_test_swapcache(src_folio) || + entry.val != src_folio->swap.val)) + return -EAGAIN; + double_pt_lock(dst_ptl, src_ptl); if (!is_pte_pages_stable(dst_pte, src_pte, orig_dst_pte, orig_src_pte, @@ -1102,6 +1112,25 @@ static int move_swap_pte(struct mm_struct *mm, struct vm_area_struct *dst_vma, if (src_folio) { folio_move_anon_rmap(src_folio, dst_vma); src_folio->index = linear_page_index(dst_vma, dst_addr); + } else { + /* + * Check if the swap entry is cached after acquiring the src_pte + * lock. Otherwise, we might miss a newly loaded swap cache folio. + * + * Check swap_map directly to minimize overhead, READ_ONCE is sufficient. + * We are trying to catch newly added swap cache, the only possible case is + * when a folio is swapped in and out again staying in swap cache, using the + * same entry before the PTE check above. The PTL is acquired and released + * twice, each time after updating the swap_map's flag. So holding + * the PTL here ensures we see the updated value. False positive is possible, + * e.g. SWP_SYNCHRONOUS_IO swapin may set the flag without touching the + * cache, or during the tiny synchronization window between swap cache and + * swap_map, but it will be gone very quickly, worst result is retry jitters. + */ + if (READ_ONCE(si->swap_map[swp_offset(entry)]) & SWAP_HAS_CACHE) { + double_pt_unlock(dst_ptl, src_ptl); + return -EAGAIN; + } } orig_src_pte = ptep_get_and_clear(mm, src_addr, src_pte); @@ -1412,7 +1441,7 @@ static int move_pages_pte(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd, } err = move_swap_pte(mm, dst_vma, dst_addr, src_addr, dst_pte, src_pte, orig_dst_pte, orig_src_pte, dst_pmd, dst_pmdval, - dst_ptl, src_ptl, src_folio); + dst_ptl, src_ptl, src_folio, si, entry); } out:

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FAILED: patch "[PATCH] maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate()" 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 fba46a5d83ca8decb338722fb4899026d8d9ead2 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025063033-shrink-submersed-b5de@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From fba46a5d83ca8decb338722fb4899026d8d9ead2 Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" <Liam.Howlett(a)oracle.com> Date: Mon, 16 Jun 2025 14:45:20 -0400 Subject: [PATCH] maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate() Temporarily clear the preallocation flag when explicitly requesting allocations. Pre-existing allocations are already counted against the request through mas_node_count_gfp(), but the allocations will not happen if the MA_STATE_PREALLOC flag is set. This flag is meant to avoid re-allocating in bulk allocation mode, and to detect issues with preallocation calculations. The MA_STATE_PREALLOC flag should also always be set on zero allocations so that detection of underflow allocations will print a WARN_ON() during consumption. User visible effect of this flaw is a WARN_ON() followed by a null pointer dereference when subsequent requests for larger number of nodes is ignored, such as the vma merge retry in mmap_region() caused by drivers altering the vma flags (which happens in v6.6, at least) Link: https://lkml.kernel.org/r/20250616184521.3382795-3-Liam.Howlett@oracle.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reported-by: Zhaoyang Huang <zhaoyang.huang(a)unisoc.com> Reported-by: Hailong Liu <hailong.liu(a)oppo.com> Link: https://lore.kernel.org/all/1652f7eb-a51b-4fee-8058-c73af63bacd1@oppo.com/ Link: https://lore.kernel.org/all/20250428184058.1416274-1-Liam.Howlett@oracle.co… Link: https://lore.kernel.org/all/20250429014754.1479118-1-Liam.Howlett@oracle.co… Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Hailong Liu <hailong.liu(a)oppo.com> Cc: zhangpeng.00(a)bytedance.com <zhangpeng.00(a)bytedance.com> Cc: Steve Kang <Steve.Kang(a)unisoc.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: Sidhartha Kumar <sidhartha.kumar(a)oracle.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/lib/maple_tree.c b/lib/maple_tree.c index affe979bd14d..00524e55a21e 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5527,8 +5527,9 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) mas->store_type = mas_wr_store_type(&wr_mas); request = mas_prealloc_calc(&wr_mas, entry); if (!request) - return ret; + goto set_flag; + mas->mas_flags &= ~MA_STATE_PREALLOC; mas_node_count_gfp(mas, request, gfp); if (mas_is_err(mas)) { mas_set_alloc_req(mas, 0); @@ -5538,6 +5539,7 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) return ret; } +set_flag: mas->mas_flags |= MA_STATE_PREALLOC; return ret; }

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FAILED: patch "[PATCH] maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate()" 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 fba46a5d83ca8decb338722fb4899026d8d9ead2 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025063032-shed-reseller-6709@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From fba46a5d83ca8decb338722fb4899026d8d9ead2 Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" <Liam.Howlett(a)oracle.com> Date: Mon, 16 Jun 2025 14:45:20 -0400 Subject: [PATCH] maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate() Temporarily clear the preallocation flag when explicitly requesting allocations. Pre-existing allocations are already counted against the request through mas_node_count_gfp(), but the allocations will not happen if the MA_STATE_PREALLOC flag is set. This flag is meant to avoid re-allocating in bulk allocation mode, and to detect issues with preallocation calculations. The MA_STATE_PREALLOC flag should also always be set on zero allocations so that detection of underflow allocations will print a WARN_ON() during consumption. User visible effect of this flaw is a WARN_ON() followed by a null pointer dereference when subsequent requests for larger number of nodes is ignored, such as the vma merge retry in mmap_region() caused by drivers altering the vma flags (which happens in v6.6, at least) Link: https://lkml.kernel.org/r/20250616184521.3382795-3-Liam.Howlett@oracle.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reported-by: Zhaoyang Huang <zhaoyang.huang(a)unisoc.com> Reported-by: Hailong Liu <hailong.liu(a)oppo.com> Link: https://lore.kernel.org/all/1652f7eb-a51b-4fee-8058-c73af63bacd1@oppo.com/ Link: https://lore.kernel.org/all/20250428184058.1416274-1-Liam.Howlett@oracle.co… Link: https://lore.kernel.org/all/20250429014754.1479118-1-Liam.Howlett@oracle.co… Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Hailong Liu <hailong.liu(a)oppo.com> Cc: zhangpeng.00(a)bytedance.com <zhangpeng.00(a)bytedance.com> Cc: Steve Kang <Steve.Kang(a)unisoc.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: Sidhartha Kumar <sidhartha.kumar(a)oracle.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/lib/maple_tree.c b/lib/maple_tree.c index affe979bd14d..00524e55a21e 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5527,8 +5527,9 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) mas->store_type = mas_wr_store_type(&wr_mas); request = mas_prealloc_calc(&wr_mas, entry); if (!request) - return ret; + goto set_flag; + mas->mas_flags &= ~MA_STATE_PREALLOC; mas_node_count_gfp(mas, request, gfp); if (mas_is_err(mas)) { mas_set_alloc_req(mas, 0); @@ -5538,6 +5539,7 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) return ret; } +set_flag: mas->mas_flags |= MA_STATE_PREALLOC; return ret; }

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FAILED: patch "[PATCH] spi: spi-cadence-quadspi: Fix pm runtime unbalance" 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 b07f349d1864abe29436f45e3047da2bdd476462 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025063009-ashamed-tipper-8da4@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From b07f349d1864abe29436f45e3047da2bdd476462 Mon Sep 17 00:00:00 2001 From: Khairul Anuar Romli <khairul.anuar.romli(a)altera.com> Date: Mon, 16 Jun 2025 09:13:53 +0800 Subject: [PATCH] spi: spi-cadence-quadspi: Fix pm runtime unbalance Having PM put sync in remove function is causing PM underflow during remove operation. This is caused by the function, runtime_pm_get_sync, not being called anywhere during the op. Ensure that calls to pm_runtime_enable()/pm_runtime_disable() and pm_runtime_get_sync()/pm_runtime_put_sync() match. echo 108d2000.spi > /sys/bus/platform/drivers/cadence-qspi/unbind [ 49.644256] Deleting MTD partitions on "108d2000.spi.0": [ 49.649575] Deleting u-boot MTD partition [ 49.684087] Deleting root MTD partition [ 49.724188] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! Continuous bind/unbind will result in an "Unbalanced pm_runtime_enable" error. Subsequent unbind attempts will return a "No such device" error, while bind attempts will return a "Resource temporarily unavailable" error. [ 47.592434] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 49.592233] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 53.232309] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 55.828550] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 57.940627] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 59.912490] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 61.876243] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 61.883000] platform 108d2000.spi: Unbalanced pm_runtime_enable! [ 532.012270] cadence-qspi 108d2000.spi: probe with driver cadence-qspi failed1 Also, change clk_disable_unprepare() to clk_disable() since continuous bind and unbind operations will trigger a warning indicating that the clock is already unprepared. Fixes: 4892b374c9b7 ("mtd: spi-nor: cadence-quadspi: Add runtime PM support") cc: stable(a)vger.kernel.org # 6.6+ Signed-off-by: Khairul Anuar Romli <khairul.anuar.romli(a)altera.com> Reviewed-by: Matthew Gerlach <matthew.gerlach(a)altera.com> Link: https://patch.msgid.link/4e7a4b8aba300e629b45a04f90bddf665fbdb335.174960187… Signed-off-by: Mark Brown <broonie(a)kernel.org> diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c index fe0f122f07b0..aa1932ba17cb 100644 --- a/drivers/spi/spi-cadence-quadspi.c +++ b/drivers/spi/spi-cadence-quadspi.c @@ -1958,10 +1958,10 @@ static int cqspi_probe(struct platform_device *pdev) goto probe_setup_failed; } - ret = devm_pm_runtime_enable(dev); - if (ret) { - if (cqspi->rx_chan) - dma_release_channel(cqspi->rx_chan); + pm_runtime_enable(dev); + + if (cqspi->rx_chan) { + dma_release_channel(cqspi->rx_chan); goto probe_setup_failed; } @@ -1981,6 +1981,7 @@ static int cqspi_probe(struct platform_device *pdev) return 0; probe_setup_failed: cqspi_controller_enable(cqspi, 0); + pm_runtime_disable(dev); probe_reset_failed: if (cqspi->is_jh7110) cqspi_jh7110_disable_clk(pdev, cqspi); @@ -1999,7 +2000,8 @@ static void cqspi_remove(struct platform_device *pdev) if (cqspi->rx_chan) dma_release_channel(cqspi->rx_chan); - clk_disable_unprepare(cqspi->clk); + if (pm_runtime_get_sync(&pdev->dev) >= 0) + clk_disable(cqspi->clk); if (cqspi->is_jh7110) cqspi_jh7110_disable_clk(pdev, cqspi);

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FAILED: patch "[PATCH] spi: spi-cadence-quadspi: Fix pm runtime unbalance" 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 b07f349d1864abe29436f45e3047da2bdd476462 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025063008-celibacy-lukewarm-7bc5@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From b07f349d1864abe29436f45e3047da2bdd476462 Mon Sep 17 00:00:00 2001 From: Khairul Anuar Romli <khairul.anuar.romli(a)altera.com> Date: Mon, 16 Jun 2025 09:13:53 +0800 Subject: [PATCH] spi: spi-cadence-quadspi: Fix pm runtime unbalance Having PM put sync in remove function is causing PM underflow during remove operation. This is caused by the function, runtime_pm_get_sync, not being called anywhere during the op. Ensure that calls to pm_runtime_enable()/pm_runtime_disable() and pm_runtime_get_sync()/pm_runtime_put_sync() match. echo 108d2000.spi > /sys/bus/platform/drivers/cadence-qspi/unbind [ 49.644256] Deleting MTD partitions on "108d2000.spi.0": [ 49.649575] Deleting u-boot MTD partition [ 49.684087] Deleting root MTD partition [ 49.724188] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! Continuous bind/unbind will result in an "Unbalanced pm_runtime_enable" error. Subsequent unbind attempts will return a "No such device" error, while bind attempts will return a "Resource temporarily unavailable" error. [ 47.592434] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 49.592233] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 53.232309] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 55.828550] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 57.940627] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 59.912490] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 61.876243] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 61.883000] platform 108d2000.spi: Unbalanced pm_runtime_enable! [ 532.012270] cadence-qspi 108d2000.spi: probe with driver cadence-qspi failed1 Also, change clk_disable_unprepare() to clk_disable() since continuous bind and unbind operations will trigger a warning indicating that the clock is already unprepared. Fixes: 4892b374c9b7 ("mtd: spi-nor: cadence-quadspi: Add runtime PM support") cc: stable(a)vger.kernel.org # 6.6+ Signed-off-by: Khairul Anuar Romli <khairul.anuar.romli(a)altera.com> Reviewed-by: Matthew Gerlach <matthew.gerlach(a)altera.com> Link: https://patch.msgid.link/4e7a4b8aba300e629b45a04f90bddf665fbdb335.174960187… Signed-off-by: Mark Brown <broonie(a)kernel.org> diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c index fe0f122f07b0..aa1932ba17cb 100644 --- a/drivers/spi/spi-cadence-quadspi.c +++ b/drivers/spi/spi-cadence-quadspi.c @@ -1958,10 +1958,10 @@ static int cqspi_probe(struct platform_device *pdev) goto probe_setup_failed; } - ret = devm_pm_runtime_enable(dev); - if (ret) { - if (cqspi->rx_chan) - dma_release_channel(cqspi->rx_chan); + pm_runtime_enable(dev); + + if (cqspi->rx_chan) { + dma_release_channel(cqspi->rx_chan); goto probe_setup_failed; } @@ -1981,6 +1981,7 @@ static int cqspi_probe(struct platform_device *pdev) return 0; probe_setup_failed: cqspi_controller_enable(cqspi, 0); + pm_runtime_disable(dev); probe_reset_failed: if (cqspi->is_jh7110) cqspi_jh7110_disable_clk(pdev, cqspi); @@ -1999,7 +2000,8 @@ static void cqspi_remove(struct platform_device *pdev) if (cqspi->rx_chan) dma_release_channel(cqspi->rx_chan); - clk_disable_unprepare(cqspi->clk); + if (pm_runtime_get_sync(&pdev->dev) >= 0) + clk_disable(cqspi->clk); if (cqspi->is_jh7110) cqspi_jh7110_disable_clk(pdev, cqspi);

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FAILED: patch "[PATCH] spi: spi-cadence-quadspi: Fix pm runtime unbalance" 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 b07f349d1864abe29436f45e3047da2bdd476462 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025063008-bonehead-poach-8e42@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From b07f349d1864abe29436f45e3047da2bdd476462 Mon Sep 17 00:00:00 2001 From: Khairul Anuar Romli <khairul.anuar.romli(a)altera.com> Date: Mon, 16 Jun 2025 09:13:53 +0800 Subject: [PATCH] spi: spi-cadence-quadspi: Fix pm runtime unbalance Having PM put sync in remove function is causing PM underflow during remove operation. This is caused by the function, runtime_pm_get_sync, not being called anywhere during the op. Ensure that calls to pm_runtime_enable()/pm_runtime_disable() and pm_runtime_get_sync()/pm_runtime_put_sync() match. echo 108d2000.spi > /sys/bus/platform/drivers/cadence-qspi/unbind [ 49.644256] Deleting MTD partitions on "108d2000.spi.0": [ 49.649575] Deleting u-boot MTD partition [ 49.684087] Deleting root MTD partition [ 49.724188] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! Continuous bind/unbind will result in an "Unbalanced pm_runtime_enable" error. Subsequent unbind attempts will return a "No such device" error, while bind attempts will return a "Resource temporarily unavailable" error. [ 47.592434] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 49.592233] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 53.232309] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 55.828550] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 57.940627] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 59.912490] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 61.876243] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 61.883000] platform 108d2000.spi: Unbalanced pm_runtime_enable! [ 532.012270] cadence-qspi 108d2000.spi: probe with driver cadence-qspi failed1 Also, change clk_disable_unprepare() to clk_disable() since continuous bind and unbind operations will trigger a warning indicating that the clock is already unprepared. Fixes: 4892b374c9b7 ("mtd: spi-nor: cadence-quadspi: Add runtime PM support") cc: stable(a)vger.kernel.org # 6.6+ Signed-off-by: Khairul Anuar Romli <khairul.anuar.romli(a)altera.com> Reviewed-by: Matthew Gerlach <matthew.gerlach(a)altera.com> Link: https://patch.msgid.link/4e7a4b8aba300e629b45a04f90bddf665fbdb335.174960187… Signed-off-by: Mark Brown <broonie(a)kernel.org> diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c index fe0f122f07b0..aa1932ba17cb 100644 --- a/drivers/spi/spi-cadence-quadspi.c +++ b/drivers/spi/spi-cadence-quadspi.c @@ -1958,10 +1958,10 @@ static int cqspi_probe(struct platform_device *pdev) goto probe_setup_failed; } - ret = devm_pm_runtime_enable(dev); - if (ret) { - if (cqspi->rx_chan) - dma_release_channel(cqspi->rx_chan); + pm_runtime_enable(dev); + + if (cqspi->rx_chan) { + dma_release_channel(cqspi->rx_chan); goto probe_setup_failed; } @@ -1981,6 +1981,7 @@ static int cqspi_probe(struct platform_device *pdev) return 0; probe_setup_failed: cqspi_controller_enable(cqspi, 0); + pm_runtime_disable(dev); probe_reset_failed: if (cqspi->is_jh7110) cqspi_jh7110_disable_clk(pdev, cqspi); @@ -1999,7 +2000,8 @@ static void cqspi_remove(struct platform_device *pdev) if (cqspi->rx_chan) dma_release_channel(cqspi->rx_chan); - clk_disable_unprepare(cqspi->clk); + if (pm_runtime_get_sync(&pdev->dev) >= 0) + clk_disable(cqspi->clk); if (cqspi->is_jh7110) cqspi_jh7110_disable_clk(pdev, cqspi);

1 day, 18 hours

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FAILED: patch "[PATCH] spi: spi-cadence-quadspi: Fix pm runtime unbalance" 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 b07f349d1864abe29436f45e3047da2bdd476462 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025063007-cruelty-mortality-e0da@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From b07f349d1864abe29436f45e3047da2bdd476462 Mon Sep 17 00:00:00 2001 From: Khairul Anuar Romli <khairul.anuar.romli(a)altera.com> Date: Mon, 16 Jun 2025 09:13:53 +0800 Subject: [PATCH] spi: spi-cadence-quadspi: Fix pm runtime unbalance Having PM put sync in remove function is causing PM underflow during remove operation. This is caused by the function, runtime_pm_get_sync, not being called anywhere during the op. Ensure that calls to pm_runtime_enable()/pm_runtime_disable() and pm_runtime_get_sync()/pm_runtime_put_sync() match. echo 108d2000.spi > /sys/bus/platform/drivers/cadence-qspi/unbind [ 49.644256] Deleting MTD partitions on "108d2000.spi.0": [ 49.649575] Deleting u-boot MTD partition [ 49.684087] Deleting root MTD partition [ 49.724188] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! Continuous bind/unbind will result in an "Unbalanced pm_runtime_enable" error. Subsequent unbind attempts will return a "No such device" error, while bind attempts will return a "Resource temporarily unavailable" error. [ 47.592434] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 49.592233] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 53.232309] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 55.828550] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 57.940627] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 59.912490] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128) [ 61.876243] cadence-qspi 108d2000.spi: Runtime PM usage count underflow! [ 61.883000] platform 108d2000.spi: Unbalanced pm_runtime_enable! [ 532.012270] cadence-qspi 108d2000.spi: probe with driver cadence-qspi failed1 Also, change clk_disable_unprepare() to clk_disable() since continuous bind and unbind operations will trigger a warning indicating that the clock is already unprepared. Fixes: 4892b374c9b7 ("mtd: spi-nor: cadence-quadspi: Add runtime PM support") cc: stable(a)vger.kernel.org # 6.6+ Signed-off-by: Khairul Anuar Romli <khairul.anuar.romli(a)altera.com> Reviewed-by: Matthew Gerlach <matthew.gerlach(a)altera.com> Link: https://patch.msgid.link/4e7a4b8aba300e629b45a04f90bddf665fbdb335.174960187… Signed-off-by: Mark Brown <broonie(a)kernel.org> diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c index fe0f122f07b0..aa1932ba17cb 100644 --- a/drivers/spi/spi-cadence-quadspi.c +++ b/drivers/spi/spi-cadence-quadspi.c @@ -1958,10 +1958,10 @@ static int cqspi_probe(struct platform_device *pdev) goto probe_setup_failed; } - ret = devm_pm_runtime_enable(dev); - if (ret) { - if (cqspi->rx_chan) - dma_release_channel(cqspi->rx_chan); + pm_runtime_enable(dev); + + if (cqspi->rx_chan) { + dma_release_channel(cqspi->rx_chan); goto probe_setup_failed; } @@ -1981,6 +1981,7 @@ static int cqspi_probe(struct platform_device *pdev) return 0; probe_setup_failed: cqspi_controller_enable(cqspi, 0); + pm_runtime_disable(dev); probe_reset_failed: if (cqspi->is_jh7110) cqspi_jh7110_disable_clk(pdev, cqspi); @@ -1999,7 +2000,8 @@ static void cqspi_remove(struct platform_device *pdev) if (cqspi->rx_chan) dma_release_channel(cqspi->rx_chan); - clk_disable_unprepare(cqspi->clk); + if (pm_runtime_get_sync(&pdev->dev) >= 0) + clk_disable(cqspi->clk); if (cqspi->is_jh7110) cqspi_jh7110_disable_clk(pdev, cqspi);

1 day, 18 hours

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FAILED: patch "[PATCH] staging: rtl8723bs: Avoid memset() in aes_cipher() and" 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 a55bc4ffc06d8c965a7d6f0a01ed0ed41380df28 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025063056-envision-frivolous-150b@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a55bc4ffc06d8c965a7d6f0a01ed0ed41380df28 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor <nathan(a)kernel.org> Date: Mon, 9 Jun 2025 14:13:14 -0700 Subject: [PATCH] staging: rtl8723bs: Avoid memset() in aes_cipher() and aes_decipher() After commit 6f110a5e4f99 ("Disable SLUB_TINY for build testing"), which causes CONFIG_KASAN to be enabled in allmodconfig again, arm64 allmodconfig builds with older versions of clang (15 through 17) show an instance of -Wframe-larger-than (which breaks the build with CONFIG_WERROR=y): drivers/staging/rtl8723bs/core/rtw_security.c:1287:5: error: stack frame size (2208) exceeds limit (2048) in 'rtw_aes_decrypt' [-Werror,-Wframe-larger-than] 1287 | u32 rtw_aes_decrypt(struct adapter *padapter, u8 *precvframe) | ^ This comes from aes_decipher() being inlined in rtw_aes_decrypt(). Running the same build with CONFIG_FRAME_WARN=128 shows aes_cipher() also uses a decent amount of stack, just under the limit of 2048: drivers/staging/rtl8723bs/core/rtw_security.c:864:19: warning: stack frame size (1952) exceeds limit (128) in 'aes_cipher' [-Wframe-larger-than] 864 | static signed int aes_cipher(u8 *key, uint hdrlen, | ^ -Rpass-analysis=stack-frame-layout only shows one large structure on the stack, which is the ctx variable inlined from aes128k128d(). A good number of the other variables come from the additional checks of fortified string routines, which are present in memset(), which both aes_cipher() and aes_decipher() use to initialize some temporary buffers. In this case, since the size is known at compile time, these additional checks should not result in any code generation changes but allmodconfig has several sanitizers enabled, which may make it harder for the compiler to eliminate the compile time checks and the variables that come about from them. The memset() calls are just initializing these buffers to zero, so use '= {}' instead, which is used all over the kernel and does the exact same thing as memset() without the fortify checks, which drops the stack usage of these functions by a few hundred kilobytes. drivers/staging/rtl8723bs/core/rtw_security.c:864:19: warning: stack frame size (1584) exceeds limit (128) in 'aes_cipher' [-Wframe-larger-than] 864 | static signed int aes_cipher(u8 *key, uint hdrlen, | ^ drivers/staging/rtl8723bs/core/rtw_security.c:1271:5: warning: stack frame size (1456) exceeds limit (128) in 'rtw_aes_decrypt' [-Wframe-larger-than] 1271 | u32 rtw_aes_decrypt(struct adapter *padapter, u8 *precvframe) | ^ Cc: stable(a)vger.kernel.org Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver") Signed-off-by: Nathan Chancellor <nathan(a)kernel.org> Reviewed-by: Dan Carpenter <dan.carpenter(a)linaro.org> Link: https://lore.kernel.org/r/20250609-rtl8723bs-fix-clang-arm64-wflt-v1-1-e2ac… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/staging/rtl8723bs/core/rtw_security.c b/drivers/staging/rtl8723bs/core/rtw_security.c index 1e9eff01b1aa..e9f382c280d9 100644 --- a/drivers/staging/rtl8723bs/core/rtw_security.c +++ b/drivers/staging/rtl8723bs/core/rtw_security.c @@ -868,29 +868,21 @@ static signed int aes_cipher(u8 *key, uint hdrlen, num_blocks, payload_index; u8 pn_vector[6]; - u8 mic_iv[16]; - u8 mic_header1[16]; - u8 mic_header2[16]; - u8 ctr_preload[16]; + u8 mic_iv[16] = {}; + u8 mic_header1[16] = {}; + u8 mic_header2[16] = {}; + u8 ctr_preload[16] = {}; /* Intermediate Buffers */ - u8 chain_buffer[16]; - u8 aes_out[16]; - u8 padded_buffer[16]; + u8 chain_buffer[16] = {}; + u8 aes_out[16] = {}; + u8 padded_buffer[16] = {}; u8 mic[8]; uint frtype = GetFrameType(pframe); uint frsubtype = GetFrameSubType(pframe); frsubtype = frsubtype>>4; - memset((void *)mic_iv, 0, 16); - memset((void *)mic_header1, 0, 16); - memset((void *)mic_header2, 0, 16); - memset((void *)ctr_preload, 0, 16); - memset((void *)chain_buffer, 0, 16); - memset((void *)aes_out, 0, 16); - memset((void *)padded_buffer, 0, 16); - if ((hdrlen == WLAN_HDR_A3_LEN) || (hdrlen == WLAN_HDR_A3_QOS_LEN)) a4_exists = 0; else @@ -1080,15 +1072,15 @@ static signed int aes_decipher(u8 *key, uint hdrlen, num_blocks, payload_index; signed int res = _SUCCESS; u8 pn_vector[6]; - u8 mic_iv[16]; - u8 mic_header1[16]; - u8 mic_header2[16]; - u8 ctr_preload[16]; + u8 mic_iv[16] = {}; + u8 mic_header1[16] = {}; + u8 mic_header2[16] = {}; + u8 ctr_preload[16] = {}; /* Intermediate Buffers */ - u8 chain_buffer[16]; - u8 aes_out[16]; - u8 padded_buffer[16]; + u8 chain_buffer[16] = {}; + u8 aes_out[16] = {}; + u8 padded_buffer[16] = {}; u8 mic[8]; uint frtype = GetFrameType(pframe); @@ -1096,14 +1088,6 @@ static signed int aes_decipher(u8 *key, uint hdrlen, frsubtype = frsubtype>>4; - memset((void *)mic_iv, 0, 16); - memset((void *)mic_header1, 0, 16); - memset((void *)mic_header2, 0, 16); - memset((void *)ctr_preload, 0, 16); - memset((void *)chain_buffer, 0, 16); - memset((void *)aes_out, 0, 16); - memset((void *)padded_buffer, 0, 16); - /* start to decrypt the payload */ num_blocks = (plen-8) / 16; /* plen including LLC, payload_length and mic) */

1 day, 18 hours

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FAILED: patch "[PATCH] x86/traps: Initialize DR7 by writing its architectural reset" 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 fa7d0f83c5c4223a01598876352473cb3d3bd4d7 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025063028-reproduce-turtle-6e00@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From fa7d0f83c5c4223a01598876352473cb3d3bd4d7 Mon Sep 17 00:00:00 2001 From: "Xin Li (Intel)" <xin(a)zytor.com> Date: Fri, 20 Jun 2025 16:15:04 -0700 Subject: [PATCH] x86/traps: Initialize DR7 by writing its architectural reset value Initialize DR7 by writing its architectural reset value to always set bit 10, which is reserved to '1', when "clearing" DR7 so as not to trigger unanticipated behavior if said bit is ever unreserved, e.g. as a feature enabling flag with inverted polarity. Signed-off-by: Xin Li (Intel) <xin(a)zytor.com> Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com> Reviewed-by: H. Peter Anvin (Intel) <hpa(a)zytor.com> Reviewed-by: Sohil Mehta <sohil.mehta(a)intel.com> Acked-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Acked-by: Sean Christopherson <seanjc(a)google.com> Tested-by: Sohil Mehta <sohil.mehta(a)intel.com> Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/20250620231504.2676902-3-xin%40zytor.com diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h index 363110e6b2e3..a2c1f2d24b64 100644 --- a/arch/x86/include/asm/debugreg.h +++ b/arch/x86/include/asm/debugreg.h @@ -9,6 +9,14 @@ #include <asm/cpufeature.h> #include <asm/msr.h> +/* + * Define bits that are always set to 1 in DR7, only bit 10 is + * architecturally reserved to '1'. + * + * This is also the init/reset value for DR7. + */ +#define DR7_FIXED_1 0x00000400 + DECLARE_PER_CPU(unsigned long, cpu_dr7); #ifndef CONFIG_PARAVIRT_XXL @@ -100,8 +108,8 @@ static __always_inline void native_set_debugreg(int regno, unsigned long value) static inline void hw_breakpoint_disable(void) { - /* Zero the control register for HW Breakpoint */ - set_debugreg(0UL, 7); + /* Reset the control register for HW Breakpoint */ + set_debugreg(DR7_FIXED_1, 7); /* Zero-out the individual HW breakpoint address registers */ set_debugreg(0UL, 0); @@ -125,9 +133,12 @@ static __always_inline unsigned long local_db_save(void) return 0; get_debugreg(dr7, 7); - dr7 &= ~0x400; /* architecturally set bit */ + + /* Architecturally set bit */ + dr7 &= ~DR7_FIXED_1; if (dr7) - set_debugreg(0, 7); + set_debugreg(DR7_FIXED_1, 7); + /* * Ensure the compiler doesn't lower the above statements into * the critical section; disabling breakpoints late would not diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index b4a391929cdb..639d9bcee842 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -31,6 +31,7 @@ #include <asm/apic.h> #include <asm/pvclock-abi.h> +#include <asm/debugreg.h> #include <asm/desc.h> #include <asm/mtrr.h> #include <asm/msr-index.h> @@ -249,7 +250,6 @@ enum x86_intercept_stage; #define DR7_BP_EN_MASK 0x000000ff #define DR7_GE (1 << 9) #define DR7_GD (1 << 13) -#define DR7_FIXED_1 0x00000400 #define DR7_VOLATILE 0xffff2bff #define KVM_GUESTDBG_VALID_MASK \ diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 0f6c280a94f0..27125e009847 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2246,7 +2246,7 @@ EXPORT_PER_CPU_SYMBOL(__stack_chk_guard); static void initialize_debug_regs(void) { /* Control register first -- to make sure everything is disabled. */ - set_debugreg(0, 7); + set_debugreg(DR7_FIXED_1, 7); set_debugreg(DR6_RESERVED, 6); /* dr5 and dr4 don't exist */ set_debugreg(0, 3); diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 102641fd2172..8b1a9733d13e 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -385,7 +385,7 @@ static void kgdb_disable_hw_debug(struct pt_regs *regs) struct perf_event *bp; /* Disable hardware debugging while we are in kgdb: */ - set_debugreg(0UL, 7); + set_debugreg(DR7_FIXED_1, 7); for (i = 0; i < HBP_NUM; i++) { if (!breakinfo[i].enabled) continue; diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index a10e180cbf23..3ef15c2f152f 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -93,7 +93,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode, /* Only print out debug registers if they are in their non-default state. */ if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) && - (d6 == DR6_RESERVED) && (d7 == 0x400)) + (d6 == DR6_RESERVED) && (d7 == DR7_FIXED_1)) return; printk("%sDR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 8d6cf25127aa..b972bf72fb8b 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -133,7 +133,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode, /* Only print out debug registers if they are in their non-default state. */ if (!((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) && - (d6 == DR6_RESERVED) && (d7 == 0x400))) { + (d6 == DR6_RESERVED) && (d7 == DR7_FIXED_1))) { printk("%sDR0: %016lx DR1: %016lx DR2: %016lx\n", log_lvl, d0, d1, d2); printk("%sDR3: %016lx DR6: %016lx DR7: %016lx\n", diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b58a74c1722d..a9d992d5652f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11035,7 +11035,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (unlikely(vcpu->arch.switch_db_regs && !(vcpu->arch.switch_db_regs & KVM_DEBUGREG_AUTO_SWITCH))) { - set_debugreg(0, 7); + set_debugreg(DR7_FIXED_1, 7); set_debugreg(vcpu->arch.eff_db[0], 0); set_debugreg(vcpu->arch.eff_db[1], 1); set_debugreg(vcpu->arch.eff_db[2], 2); @@ -11044,7 +11044,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (unlikely(vcpu->arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)) kvm_x86_call(set_dr6)(vcpu, vcpu->arch.dr6); } else if (unlikely(hw_breakpoint_active())) { - set_debugreg(0, 7); + set_debugreg(DR7_FIXED_1, 7); } vcpu->arch.host_debugctl = get_debugctlmsr();

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FAILED: patch "[PATCH] x86/traps: Initialize DR7 by writing its architectural reset" 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 fa7d0f83c5c4223a01598876352473cb3d3bd4d7 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025063027-myspace-germproof-6a5c@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From fa7d0f83c5c4223a01598876352473cb3d3bd4d7 Mon Sep 17 00:00:00 2001 From: "Xin Li (Intel)" <xin(a)zytor.com> Date: Fri, 20 Jun 2025 16:15:04 -0700 Subject: [PATCH] x86/traps: Initialize DR7 by writing its architectural reset value Initialize DR7 by writing its architectural reset value to always set bit 10, which is reserved to '1', when "clearing" DR7 so as not to trigger unanticipated behavior if said bit is ever unreserved, e.g. as a feature enabling flag with inverted polarity. Signed-off-by: Xin Li (Intel) <xin(a)zytor.com> Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com> Reviewed-by: H. Peter Anvin (Intel) <hpa(a)zytor.com> Reviewed-by: Sohil Mehta <sohil.mehta(a)intel.com> Acked-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Acked-by: Sean Christopherson <seanjc(a)google.com> Tested-by: Sohil Mehta <sohil.mehta(a)intel.com> Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/20250620231504.2676902-3-xin%40zytor.com diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h index 363110e6b2e3..a2c1f2d24b64 100644 --- a/arch/x86/include/asm/debugreg.h +++ b/arch/x86/include/asm/debugreg.h @@ -9,6 +9,14 @@ #include <asm/cpufeature.h> #include <asm/msr.h> +/* + * Define bits that are always set to 1 in DR7, only bit 10 is + * architecturally reserved to '1'. + * + * This is also the init/reset value for DR7. + */ +#define DR7_FIXED_1 0x00000400 + DECLARE_PER_CPU(unsigned long, cpu_dr7); #ifndef CONFIG_PARAVIRT_XXL @@ -100,8 +108,8 @@ static __always_inline void native_set_debugreg(int regno, unsigned long value) static inline void hw_breakpoint_disable(void) { - /* Zero the control register for HW Breakpoint */ - set_debugreg(0UL, 7); + /* Reset the control register for HW Breakpoint */ + set_debugreg(DR7_FIXED_1, 7); /* Zero-out the individual HW breakpoint address registers */ set_debugreg(0UL, 0); @@ -125,9 +133,12 @@ static __always_inline unsigned long local_db_save(void) return 0; get_debugreg(dr7, 7); - dr7 &= ~0x400; /* architecturally set bit */ + + /* Architecturally set bit */ + dr7 &= ~DR7_FIXED_1; if (dr7) - set_debugreg(0, 7); + set_debugreg(DR7_FIXED_1, 7); + /* * Ensure the compiler doesn't lower the above statements into * the critical section; disabling breakpoints late would not diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index b4a391929cdb..639d9bcee842 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -31,6 +31,7 @@ #include <asm/apic.h> #include <asm/pvclock-abi.h> +#include <asm/debugreg.h> #include <asm/desc.h> #include <asm/mtrr.h> #include <asm/msr-index.h> @@ -249,7 +250,6 @@ enum x86_intercept_stage; #define DR7_BP_EN_MASK 0x000000ff #define DR7_GE (1 << 9) #define DR7_GD (1 << 13) -#define DR7_FIXED_1 0x00000400 #define DR7_VOLATILE 0xffff2bff #define KVM_GUESTDBG_VALID_MASK \ diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 0f6c280a94f0..27125e009847 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2246,7 +2246,7 @@ EXPORT_PER_CPU_SYMBOL(__stack_chk_guard); static void initialize_debug_regs(void) { /* Control register first -- to make sure everything is disabled. */ - set_debugreg(0, 7); + set_debugreg(DR7_FIXED_1, 7); set_debugreg(DR6_RESERVED, 6); /* dr5 and dr4 don't exist */ set_debugreg(0, 3); diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 102641fd2172..8b1a9733d13e 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -385,7 +385,7 @@ static void kgdb_disable_hw_debug(struct pt_regs *regs) struct perf_event *bp; /* Disable hardware debugging while we are in kgdb: */ - set_debugreg(0UL, 7); + set_debugreg(DR7_FIXED_1, 7); for (i = 0; i < HBP_NUM; i++) { if (!breakinfo[i].enabled) continue; diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index a10e180cbf23..3ef15c2f152f 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -93,7 +93,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode, /* Only print out debug registers if they are in their non-default state. */ if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) && - (d6 == DR6_RESERVED) && (d7 == 0x400)) + (d6 == DR6_RESERVED) && (d7 == DR7_FIXED_1)) return; printk("%sDR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 8d6cf25127aa..b972bf72fb8b 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -133,7 +133,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode, /* Only print out debug registers if they are in their non-default state. */ if (!((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) && - (d6 == DR6_RESERVED) && (d7 == 0x400))) { + (d6 == DR6_RESERVED) && (d7 == DR7_FIXED_1))) { printk("%sDR0: %016lx DR1: %016lx DR2: %016lx\n", log_lvl, d0, d1, d2); printk("%sDR3: %016lx DR6: %016lx DR7: %016lx\n", diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b58a74c1722d..a9d992d5652f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11035,7 +11035,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (unlikely(vcpu->arch.switch_db_regs && !(vcpu->arch.switch_db_regs & KVM_DEBUGREG_AUTO_SWITCH))) { - set_debugreg(0, 7); + set_debugreg(DR7_FIXED_1, 7); set_debugreg(vcpu->arch.eff_db[0], 0); set_debugreg(vcpu->arch.eff_db[1], 1); set_debugreg(vcpu->arch.eff_db[2], 2); @@ -11044,7 +11044,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (unlikely(vcpu->arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)) kvm_x86_call(set_dr6)(vcpu, vcpu->arch.dr6); } else if (unlikely(hw_breakpoint_active())) { - set_debugreg(0, 7); + set_debugreg(DR7_FIXED_1, 7); } vcpu->arch.host_debugctl = get_debugctlmsr();

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