October 2024 - Linux-stable-mirror

FAILED: patch "[PATCH] maple_tree: correct tree corruption on spanning store" 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 bea07fd63192b61209d48cbb81ef474cc3ee4c62 # <… [View More]resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024101818-ducky-dallying-2814@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From bea07fd63192b61209d48cbb81ef474cc3ee4c62 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Date: Mon, 7 Oct 2024 16:28:32 +0100 Subject: [PATCH] maple_tree: correct tree corruption on spanning store Patch series "maple_tree: correct tree corruption on spanning store", v3. There has been a nasty yet subtle maple tree corruption bug that appears to have been in existence since the inception of the algorithm. This bug seems far more likely to happen since commit f8d112a4e657 ("mm/mmap: avoid zeroing vma tree in mmap_region()"), which is the point at which reports started to be submitted concerning this bug. We were made definitely aware of the bug thanks to the kind efforts of Bert Karwatzki who helped enormously in my being able to track this down and identify the cause of it. The bug arises when an attempt is made to perform a spanning store across two leaf nodes, where the right leaf node is the rightmost child of the shared parent, AND the store completely consumes the right-mode node. This results in mas_wr_spanning_store() mitakenly duplicating the new and existing entries at the maximum pivot within the range, and thus maple tree corruption. The fix patch corrects this by detecting this scenario and disallowing the mistaken duplicate copy. The fix patch commit message goes into great detail as to how this occurs. This series also includes a test which reliably reproduces the issue, and asserts that the fix works correctly. Bert has kindly tested the fix and confirmed it resolved his issues. Also Mikhail Gavrilov kindly reported what appears to be precisely the same bug, which this fix should also resolve. This patch (of 2): There has been a subtle bug present in the maple tree implementation from its inception. This arises from how stores are performed - when a store occurs, it will overwrite overlapping ranges and adjust the tree as necessary to accommodate this. A range may always ultimately span two leaf nodes. In this instance we walk the two leaf nodes, determine which elements are not overwritten to the left and to the right of the start and end of the ranges respectively and then rebalance the tree to contain these entries and the newly inserted one. This kind of store is dubbed a 'spanning store' and is implemented by mas_wr_spanning_store(). In order to reach this stage, mas_store_gfp() invokes mas_wr_preallocate(), mas_wr_store_type() and mas_wr_walk() in turn to walk the tree and update the object (mas) to traverse to the location where the write should be performed, determining its store type. When a spanning store is required, this function returns false stopping at the parent node which contains the target range, and mas_wr_store_type() marks the mas->store_type as wr_spanning_store to denote this fact. When we go to perform the store in mas_wr_spanning_store(), we first determine the elements AFTER the END of the range we wish to store (that is, to the right of the entry to be inserted) - we do this by walking to the NEXT pivot in the tree (i.e. r_mas.last + 1), starting at the node we have just determined contains the range over which we intend to write. We then turn our attention to the entries to the left of the entry we are inserting, whose state is represented by l_mas, and copy these into a 'big node', which is a special node which contains enough slots to contain two leaf node's worth of data. We then copy the entry we wish to store immediately after this - the copy and the insertion of the new entry is performed by mas_store_b_node(). After this we copy the elements to the right of the end of the range which we are inserting, if we have not exceeded the length of the node (i.e. r_mas.offset <= r_mas.end). Herein lies the bug - under very specific circumstances, this logic can break and corrupt the maple tree. Consider the following tree: Height 0 Root Node / \ pivot = 0xffff / \ pivot = ULONG_MAX / \ 1 A [-----] ... / \ pivot = 0x4fff / \ pivot = 0xffff / \ 2 (LEAVES) B [-----] [-----] C ^--- Last pivot 0xffff. Now imagine we wish to store an entry in the range [0x4000, 0xffff] (note that all ranges expressed in maple tree code are inclusive): 1. mas_store_gfp() descends the tree, finds node A at <=0xffff, then determines that this is a spanning store across nodes B and C. The mas state is set such that the current node from which we traverse further is node A. 2. In mas_wr_spanning_store() we try to find elements to the right of pivot 0xffff by searching for an index of 0x10000: - mas_wr_walk_index() invokes mas_wr_walk_descend() and mas_wr_node_walk() in turn. - mas_wr_node_walk() loops over entries in node A until EITHER it finds an entry whose pivot equals or exceeds 0x10000 OR it reaches the final entry. - Since no entry has a pivot equal to or exceeding 0x10000, pivot 0xffff is selected, leading to node C. - mas_wr_walk_traverse() resets the mas state to traverse node C. We loop around and invoke mas_wr_walk_descend() and mas_wr_node_walk() in turn once again. - Again, we reach the last entry in node C, which has a pivot of 0xffff. 3. We then copy the elements to the left of 0x4000 in node B to the big node via mas_store_b_node(), and insert the new [0x4000, 0xffff] entry too. 4. We determine whether we have any entries to copy from the right of the end of the range via - and with r_mas set up at the entry at pivot 0xffff, r_mas.offset <= r_mas.end, and then we DUPLICATE the entry at pivot 0xffff. 5. BUG! The maple tree is corrupted with a duplicate entry. This requires a very specific set of circumstances - we must be spanning the last element in a leaf node, which is the last element in the parent node. spanning store across two leaf nodes with a range that ends at that shared pivot. A potential solution to this problem would simply be to reset the walk each time we traverse r_mas, however given the rarity of this situation it seems that would be rather inefficient. Instead, this patch detects if the right hand node is populated, i.e. has anything we need to copy. We do so by only copying elements from the right of the entry being inserted when the maximum value present exceeds the last, rather than basing this on offset position. The patch also updates some comments and eliminates the unused bool return value in mas_wr_walk_index(). The work performed in commit f8d112a4e657 ("mm/mmap: avoid zeroing vma tree in mmap_region()") seems to have made the probability of this event much more likely, which is the point at which reports started to be submitted concerning this bug. The motivation for this change arose from Bert Karwatzki's report of encountering mm instability after the release of kernel v6.12-rc1 which, after the use of CONFIG_DEBUG_VM_MAPLE_TREE and similar configuration options, was identified as maple tree corruption. After Bert very generously provided his time and ability to reproduce this event consistently, I was able to finally identify that the issue discussed in this commit message was occurring for him. Link: https://lkml.kernel.org/r/cover.1728314402.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/48b349a2a0f7c76e18772712d0997a5e12ab0a3b.17283144… Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Bert Karwatzki <spasswolf(a)web.de> Closes: https://lore.kernel.org/all/20241001023402.3374-1-spasswolf@web.de/ Tested-by: Bert Karwatzki <spasswolf(a)web.de> Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov(a)gmail.com> Closes: https://lore.kernel.org/all/CABXGCsOPwuoNOqSMmAvWO2Fz4TEmPnjFj-b7iF+XFRu1h7… Acked-by: Vlastimil Babka <vbabka(a)suse.cz> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)Oracle.com> Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov(a)gmail.com> Reviewed-by: Wei Yang <richard.weiyang(a)gmail.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 ce7c7a7a8258..3619301dda2e 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -2196,6 +2196,8 @@ static inline void mas_node_or_none(struct ma_state *mas, /* * mas_wr_node_walk() - Find the correct offset for the index in the @mas. + * If @mas->index cannot be found within the containing + * node, we traverse to the last entry in the node. * @wr_mas: The maple write state * * Uses mas_slot_locked() and does not need to worry about dead nodes. @@ -3532,7 +3534,7 @@ static bool mas_wr_walk(struct ma_wr_state *wr_mas) return true; } -static bool mas_wr_walk_index(struct ma_wr_state *wr_mas) +static void mas_wr_walk_index(struct ma_wr_state *wr_mas) { struct ma_state *mas = wr_mas->mas; @@ -3541,11 +3543,9 @@ static bool mas_wr_walk_index(struct ma_wr_state *wr_mas) wr_mas->content = mas_slot_locked(mas, wr_mas->slots, mas->offset); if (ma_is_leaf(wr_mas->type)) - return true; + return; mas_wr_walk_traverse(wr_mas); - } - return true; } /* * mas_extend_spanning_null() - Extend a store of a %NULL to include surrounding %NULLs. @@ -3765,8 +3765,8 @@ static noinline void mas_wr_spanning_store(struct ma_wr_state *wr_mas) memset(&b_node, 0, sizeof(struct maple_big_node)); /* Copy l_mas and store the value in b_node. */ mas_store_b_node(&l_wr_mas, &b_node, l_mas.end); - /* Copy r_mas into b_node. */ - if (r_mas.offset <= r_mas.end) + /* Copy r_mas into b_node if there is anything to copy. */ + if (r_mas.max > r_mas.last) mas_mab_cp(&r_mas, r_mas.offset, r_mas.end, &b_node, b_node.b_end + 1); else [View Less]

6 months, 1 week

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[PATCH 5.10 0/1] soundwire: cadence: Fix error check in cdns_xfer_msg()

by Daniil Dulov

Svacer reports redundant comparison in cdns_xfer_msg(). The problem is present in 5.10 stable release and can be fixed by the following upstream patch that can be cleanly applied to 5.10 stable branch.

6 months, 1 week

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[PATCH 5.15.y 5.10.y 5.4.y] wifi: mac80211: fix potential key use-after-free

by Sherry Yang

From: Johannes Berg <johannes.berg(a)intel.com> [ Upstream commit 31db78a4923ef5e2008f2eed321811ca79e7f71b ] When ieee80211_key_link() is called by ieee80211_gtk_rekey_add() but returns 0 due to KRACK protection (identical key reinstall), ieee80211_gtk_rekey_add() will still return a pointer into the key, in a potential use-after-free. This normally doesn't happen since it's only called by iwlwifi in case of WoWLAN rekey offload which has its own KRACK protection, but still better to … [View More]

6 months, 1 week

2
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[PATCH 6.1.y] nvme: fix metadata handling in nvme-passthrough

by Puranjay Mohan

[ Upstream commit 7c2fd76048e95dd267055b5f5e0a48e6e7c81fd9 ] On an NVMe namespace that does not support metadata, it is possible to send an IO command with metadata through io-passthru. This allows issues like [1] to trigger in the completion code path. nvme_map_user_request() doesn't check if the namespace supports metadata before sending it forward. It also allows admin commands with metadata to be processed as it ignores metadata when bdev == NULL and may report success. Reject an IO … [View More]

6 months, 1 week

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[PATCH stable 6.1 0/2] devlink: Fix RCU stall when unregistering a devlink instance

by Ido Schimmel

Upstream commit c2368b19807a ("net: devlink: introduce "unregistering" mark and use it during devlinks iteration") in v6.0 introduced a race when unregistering a devlink instance that can result in RCU stalls and in the system completely locking up. Exact details and reproducer can be found here [1]. The bug was inadvertently fixed in v6.3 by upstream commit d77278196441 ("devlink: bump the instance index directly when iterating"). This patchset fixes the bug by backporting the second commit … [View More]

6 months, 1 week

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FAILED: patch "[PATCH] secretmem: disable memfd_secret() if arch cannot set direct" 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 532b53cebe58f34ce1c0f34d866f5c0e335c53c6 # <… [View More]resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024101412-prowling-snowflake-9fe0@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: 532b53cebe58 ("secretmem: disable memfd_secret() if arch cannot set direct map") f7c5b1aab5ef ("mm/secretmem: remove reduntant return value") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 532b53cebe58f34ce1c0f34d866f5c0e335c53c6 Mon Sep 17 00:00:00 2001 From: Patrick Roy <roypat(a)amazon.co.uk> Date: Tue, 1 Oct 2024 09:00:41 +0100 Subject: [PATCH] secretmem: disable memfd_secret() if arch cannot set direct map Return -ENOSYS from memfd_secret() syscall if !can_set_direct_map(). This is the case for example on some arm64 configurations, where marking 4k PTEs in the direct map not present can only be done if the direct map is set up at 4k granularity in the first place (as ARM's break-before-make semantics do not easily allow breaking apart large/gigantic pages). More precisely, on arm64 systems with !can_set_direct_map(), set_direct_map_invalid_noflush() is a no-op, however it returns success (0) instead of an error. This means that memfd_secret will seemingly "work" (e.g. syscall succeeds, you can mmap the fd and fault in pages), but it does not actually achieve its goal of removing its memory from the direct map. Note that with this patch, memfd_secret() will start erroring on systems where can_set_direct_map() returns false (arm64 with CONFIG_RODATA_FULL_DEFAULT_ENABLED=n, CONFIG_DEBUG_PAGEALLOC=n and CONFIG_KFENCE=n), but that still seems better than the current silent failure. Since CONFIG_RODATA_FULL_DEFAULT_ENABLED defaults to 'y', most arm64 systems actually have a working memfd_secret() and aren't be affected. From going through the iterations of the original memfd_secret patch series, it seems that disabling the syscall in these scenarios was the intended behavior [1] (preferred over having set_direct_map_invalid_noflush return an error as that would result in SIGBUSes at page-fault time), however the check for it got dropped between v16 [2] and v17 [3], when secretmem moved away from CMA allocations. [1]: https://lore.kernel.org/lkml/20201124164930.GK8537@kernel.org/ [2]: https://lore.kernel.org/lkml/20210121122723.3446-11-rppt@kernel.org/#t [3]: https://lore.kernel.org/lkml/20201125092208.12544-10-rppt@kernel.org/ Link: https://lkml.kernel.org/r/20241001080056.784735-1-roypat@amazon.co.uk Fixes: 1507f51255c9 ("mm: introduce memfd_secret system call to create "secret" memory areas") Signed-off-by: Patrick Roy <roypat(a)amazon.co.uk> Reviewed-by: Mike Rapoport (Microsoft) <rppt(a)kernel.org> Cc: Alexander Graf <graf(a)amazon.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: James Gowans <jgowans(a)amazon.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/secretmem.c b/mm/secretmem.c index 3afb5ad701e1..399552814fd0 100644 --- a/mm/secretmem.c +++ b/mm/secretmem.c @@ -238,7 +238,7 @@ SYSCALL_DEFINE1(memfd_secret, unsigned int, flags) /* make sure local flags do not confict with global fcntl.h */ BUILD_BUG_ON(SECRETMEM_FLAGS_MASK & O_CLOEXEC); - if (!secretmem_enable) + if (!secretmem_enable || !can_set_direct_map()) return -ENOSYS; if (flags & ~(SECRETMEM_FLAGS_MASK | O_CLOEXEC)) @@ -280,7 +280,7 @@ static struct file_system_type secretmem_fs = { static int __init secretmem_init(void) { - if (!secretmem_enable) + if (!secretmem_enable || !can_set_direct_map()) return 0; secretmem_mnt = kern_mount(&secretmem_fs); [View Less]

6 months, 1 week

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[PATCH 6.6 00/21] xfs backports for 6.6.y (from 6.10)

by Catherine Hoang

Hello, This series contains backports for 6.6 from the 6.10 release. This patchset has gone through xfs testing and review. Christoph Hellwig (4): xfs: fix error returns from xfs_bmapi_write xfs: fix xfs_bmap_add_extent_delay_real for partial conversions xfs: remove a racy if_bytes check in xfs_reflink_end_cow_extent xfs: fix freeing speculative preallocations for preallocated files Darrick J. Wong (11): xfs: require XFS_SB_FEAT_INCOMPAT_LOG_XATTRS for attr log intent item … [View More]recovery xfs: check opcode and iovec count match in xlog_recover_attri_commit_pass2 xfs: fix missing check for invalid attr flags xfs: check shortform attr entry flags specifically xfs: validate recovered name buffers when recovering xattr items xfs: enforce one namespace per attribute xfs: revert commit 44af6c7e59b12 xfs: use dontcache for grabbing inodes during scrub xfs: allow symlinks with short remote targets xfs: restrict when we try to align cow fork delalloc to cowextsz hints xfs: allow unlinked symlinks and dirs with zero size Dave Chinner (1): xfs: fix unlink vs cluster buffer instantiation race Wengang Wang (1): xfs: make sure sb_fdblocks is non-negative Zhang Yi (4): xfs: match lock mode in xfs_buffered_write_iomap_begin() xfs: make the seq argument to xfs_bmapi_convert_delalloc() optional xfs: make xfs_bmapi_convert_delalloc() to allocate the target offset xfs: convert delayed extents to unwritten when zeroing post eof blocks fs/xfs/libxfs/xfs_attr.c | 11 +++ fs/xfs/libxfs/xfs_attr.h | 4 +- fs/xfs/libxfs/xfs_attr_leaf.c | 6 +- fs/xfs/libxfs/xfs_attr_remote.c | 1 - fs/xfs/libxfs/xfs_bmap.c | 130 ++++++++++++++++++++++++++------ fs/xfs/libxfs/xfs_da_btree.c | 20 ++--- fs/xfs/libxfs/xfs_da_format.h | 5 ++ fs/xfs/libxfs/xfs_inode_buf.c | 47 ++++++++++-- fs/xfs/libxfs/xfs_sb.c | 7 +- fs/xfs/scrub/attr.c | 47 +++++++----- fs/xfs/scrub/common.c | 12 +-- fs/xfs/scrub/scrub.h | 7 ++ fs/xfs/xfs_aops.c | 54 ++++--------- fs/xfs/xfs_attr_item.c | 98 ++++++++++++++++++++---- fs/xfs/xfs_attr_list.c | 11 ++- fs/xfs/xfs_bmap_util.c | 61 +++++++++------ fs/xfs/xfs_bmap_util.h | 2 +- fs/xfs/xfs_dquot.c | 1 - fs/xfs/xfs_icache.c | 2 +- fs/xfs/xfs_inode.c | 37 +++++---- fs/xfs/xfs_iomap.c | 81 +++++++++++--------- fs/xfs/xfs_reflink.c | 20 ----- fs/xfs/xfs_rtalloc.c | 2 - 23 files changed, 433 insertions(+), 233 deletions(-) -- 2.39.3 [View Less]

6 months, 1 week

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FAILED: patch "[PATCH] mm: don't install PMD mappings when THPs are disabled by the" failed to apply to 6.11-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.11-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-6.11.y git checkout FETCH_HEAD git cherry-pick -x 2b0f922323ccfa76219bcaacd35cd50aeaa1359 # <… [View More]resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024101841-keep-coma-4963@gregkh' --subject-prefix 'PATCH 6.11.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2b0f922323ccfa76219bcaacd35cd50aeaa13592 Mon Sep 17 00:00:00 2001 From: David Hildenbrand <david(a)redhat.com> Date: Fri, 11 Oct 2024 12:24:45 +0200 Subject: [PATCH] mm: don't install PMD mappings when THPs are disabled by the hw/process/vma We (or rather, readahead logic :) ) might be allocating a THP in the pagecache and then try mapping it into a process that explicitly disabled THP: we might end up installing PMD mappings. This is a problem for s390x KVM, which explicitly remaps all PMD-mapped THPs to be PTE-mapped in s390_enable_sie()->thp_split_mm(), before starting the VM. For example, starting a VM backed on a file system with large folios supported makes the VM crash when the VM tries accessing such a mapping using KVM. Is it also a problem when the HW disabled THP using TRANSPARENT_HUGEPAGE_UNSUPPORTED? At least on x86 this would be the case without X86_FEATURE_PSE. In the future, we might be able to do better on s390x and only disallow PMD mappings -- what s390x and likely TRANSPARENT_HUGEPAGE_UNSUPPORTED really wants. For now, fix it by essentially performing the same check as would be done in __thp_vma_allowable_orders() or in shmem code, where this works as expected, and disallow PMD mappings, making us fallback to PTE mappings. Link: https://lkml.kernel.org/r/20241011102445.934409-3-david@redhat.com Fixes: 793917d997df ("mm/readahead: Add large folio readahead") Signed-off-by: David Hildenbrand <david(a)redhat.com> Reported-by: Leo Fu <bfu(a)redhat.com> Tested-by: Thomas Huth <thuth(a)redhat.com> Cc: Thomas Huth <thuth(a)redhat.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Ryan Roberts <ryan.roberts(a)arm.com> Cc: Christian Borntraeger <borntraeger(a)linux.ibm.com> Cc: Janosch Frank <frankja(a)linux.ibm.com> Cc: Claudio Imbrenda <imbrenda(a)linux.ibm.com> Cc: Hugh Dickins <hughd(a)google.com> Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/memory.c b/mm/memory.c index c0869a962ddd..30feedabc932 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4920,6 +4920,15 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) pmd_t entry; vm_fault_t ret = VM_FAULT_FALLBACK; + /* + * It is too late to allocate a small folio, we already have a large + * folio in the pagecache: especially s390 KVM cannot tolerate any + * PMD mappings, but PTE-mapped THP are fine. So let's simply refuse any + * PMD mappings if THPs are disabled. + */ + if (thp_disabled_by_hw() || vma_thp_disabled(vma, vma->vm_flags)) + return ret; + if (!thp_vma_suitable_order(vma, haddr, PMD_ORDER)) return ret; [View Less]

6 months, 1 week

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FAILED: patch "[PATCH] mm: huge_memory: add vma_thp_disabled() and" 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 963756aac1f011d904ddd9548ae82286d3a91f96 # <… [View More]resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024101848-lucid-mountain-2cdf@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 963756aac1f011d904ddd9548ae82286d3a91f96 Mon Sep 17 00:00:00 2001 From: Kefeng Wang <wangkefeng.wang(a)huawei.com> Date: Fri, 11 Oct 2024 12:24:44 +0200 Subject: [PATCH] mm: huge_memory: add vma_thp_disabled() and thp_disabled_by_hw() Patch series "mm: don't install PMD mappings when THPs are disabled by the hw/process/vma". During testing, it was found that we can get PMD mappings in processes where THP (and more precisely, PMD mappings) are supposed to be disabled. While it works as expected for anon+shmem, the pagecache is the problematic bit. For s390 KVM this currently means that a VM backed by a file located on filesystem with large folio support can crash when KVM tries accessing the problematic page, because the readahead logic might decide to use a PMD-sized THP and faulting it into the page tables will install a PMD mapping, something that s390 KVM cannot tolerate. This might also be a problem with HW that does not support PMD mappings, but I did not try reproducing it. Fix it by respecting the ways to disable THPs when deciding whether we can install a PMD mapping. khugepaged should already be taking care of not collapsing if THPs are effectively disabled for the hw/process/vma. This patch (of 2): Add vma_thp_disabled() and thp_disabled_by_hw() helpers to be shared by shmem_allowable_huge_orders() and __thp_vma_allowable_orders(). [david(a)redhat.com: rename to vma_thp_disabled(), split out thp_disabled_by_hw() ] Link: https://lkml.kernel.org/r/20241011102445.934409-2-david@redhat.com Fixes: 793917d997df ("mm/readahead: Add large folio readahead") Signed-off-by: Kefeng Wang <wangkefeng.wang(a)huawei.com> Signed-off-by: David Hildenbrand <david(a)redhat.com> Reported-by: Leo Fu <bfu(a)redhat.com> Tested-by: Thomas Huth <thuth(a)redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts(a)arm.com> Cc: Boqiao Fu <bfu(a)redhat.com> Cc: Christian Borntraeger <borntraeger(a)linux.ibm.com> Cc: Claudio Imbrenda <imbrenda(a)linux.ibm.com> Cc: Hugh Dickins <hughd(a)google.com> Cc: Janosch Frank <frankja(a)linux.ibm.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 67d0ab3c3bba..ef5b80e48599 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -322,6 +322,24 @@ struct thpsize { (transparent_hugepage_flags & \ (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG)) +static inline bool vma_thp_disabled(struct vm_area_struct *vma, + unsigned long vm_flags) +{ + /* + * Explicitly disabled through madvise or prctl, or some + * architectures may disable THP for some mappings, for + * example, s390 kvm. + */ + return (vm_flags & VM_NOHUGEPAGE) || + test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags); +} + +static inline bool thp_disabled_by_hw(void) +{ + /* If the hardware/firmware marked hugepage support disabled. */ + return transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED); +} + unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); unsigned long thp_get_unmapped_area_vmflags(struct file *filp, unsigned long addr, diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 87b49ecc7b1e..2fb328880b50 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -109,18 +109,7 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma, if (!vma->vm_mm) /* vdso */ return 0; - /* - * Explicitly disabled through madvise or prctl, or some - * architectures may disable THP for some mappings, for - * example, s390 kvm. - * */ - if ((vm_flags & VM_NOHUGEPAGE) || - test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) - return 0; - /* - * If the hardware/firmware marked hugepage support disabled. - */ - if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED)) + if (thp_disabled_by_hw() || vma_thp_disabled(vma, vm_flags)) return 0; /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ diff --git a/mm/shmem.c b/mm/shmem.c index 4f11b5506363..c5adb987b23c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1664,12 +1664,7 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode, loff_t i_size; int order; - if (vma && ((vm_flags & VM_NOHUGEPAGE) || - test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))) - return 0; - - /* If the hardware/firmware marked hugepage support disabled. */ - if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED)) + if (thp_disabled_by_hw() || (vma && vma_thp_disabled(vma, vm_flags))) return 0; global_huge = shmem_huge_global_enabled(inode, index, write_end, [View Less]

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FAILED: patch "[PATCH] mm: huge_memory: add vma_thp_disabled() and" 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 963756aac1f011d904ddd9548ae82286d3a91f96 # <… [View More]resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024101842-flatness-osmosis-b08e@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 963756aac1f011d904ddd9548ae82286d3a91f96 Mon Sep 17 00:00:00 2001 From: Kefeng Wang <wangkefeng.wang(a)huawei.com> Date: Fri, 11 Oct 2024 12:24:44 +0200 Subject: [PATCH] mm: huge_memory: add vma_thp_disabled() and thp_disabled_by_hw() Patch series "mm: don't install PMD mappings when THPs are disabled by the hw/process/vma". During testing, it was found that we can get PMD mappings in processes where THP (and more precisely, PMD mappings) are supposed to be disabled. While it works as expected for anon+shmem, the pagecache is the problematic bit. For s390 KVM this currently means that a VM backed by a file located on filesystem with large folio support can crash when KVM tries accessing the problematic page, because the readahead logic might decide to use a PMD-sized THP and faulting it into the page tables will install a PMD mapping, something that s390 KVM cannot tolerate. This might also be a problem with HW that does not support PMD mappings, but I did not try reproducing it. Fix it by respecting the ways to disable THPs when deciding whether we can install a PMD mapping. khugepaged should already be taking care of not collapsing if THPs are effectively disabled for the hw/process/vma. This patch (of 2): Add vma_thp_disabled() and thp_disabled_by_hw() helpers to be shared by shmem_allowable_huge_orders() and __thp_vma_allowable_orders(). [david(a)redhat.com: rename to vma_thp_disabled(), split out thp_disabled_by_hw() ] Link: https://lkml.kernel.org/r/20241011102445.934409-2-david@redhat.com Fixes: 793917d997df ("mm/readahead: Add large folio readahead") Signed-off-by: Kefeng Wang <wangkefeng.wang(a)huawei.com> Signed-off-by: David Hildenbrand <david(a)redhat.com> Reported-by: Leo Fu <bfu(a)redhat.com> Tested-by: Thomas Huth <thuth(a)redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts(a)arm.com> Cc: Boqiao Fu <bfu(a)redhat.com> Cc: Christian Borntraeger <borntraeger(a)linux.ibm.com> Cc: Claudio Imbrenda <imbrenda(a)linux.ibm.com> Cc: Hugh Dickins <hughd(a)google.com> Cc: Janosch Frank <frankja(a)linux.ibm.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 67d0ab3c3bba..ef5b80e48599 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -322,6 +322,24 @@ struct thpsize { (transparent_hugepage_flags & \ (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG)) +static inline bool vma_thp_disabled(struct vm_area_struct *vma, + unsigned long vm_flags) +{ + /* + * Explicitly disabled through madvise or prctl, or some + * architectures may disable THP for some mappings, for + * example, s390 kvm. + */ + return (vm_flags & VM_NOHUGEPAGE) || + test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags); +} + +static inline bool thp_disabled_by_hw(void) +{ + /* If the hardware/firmware marked hugepage support disabled. */ + return transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED); +} + unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); unsigned long thp_get_unmapped_area_vmflags(struct file *filp, unsigned long addr, diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 87b49ecc7b1e..2fb328880b50 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -109,18 +109,7 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma, if (!vma->vm_mm) /* vdso */ return 0; - /* - * Explicitly disabled through madvise or prctl, or some - * architectures may disable THP for some mappings, for - * example, s390 kvm. - * */ - if ((vm_flags & VM_NOHUGEPAGE) || - test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) - return 0; - /* - * If the hardware/firmware marked hugepage support disabled. - */ - if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED)) + if (thp_disabled_by_hw() || vma_thp_disabled(vma, vm_flags)) return 0; /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ diff --git a/mm/shmem.c b/mm/shmem.c index 4f11b5506363..c5adb987b23c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1664,12 +1664,7 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode, loff_t i_size; int order; - if (vma && ((vm_flags & VM_NOHUGEPAGE) || - test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))) - return 0; - - /* If the hardware/firmware marked hugepage support disabled. */ - if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED)) + if (thp_disabled_by_hw() || (vma && vma_thp_disabled(vma, vm_flags))) return 0; global_huge = shmem_huge_global_enabled(inode, index, write_end, [View Less]

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