- 12 Sep, 2022 40 commits
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David Hildenbrand authored
commit 6c287605 ("mm: remember exclusively mapped anonymous pages with PG_anon_exclusive") made sure that when PageAnonExclusive() has to be cleared during temporary unmapping of a page, that the PTE is cleared/invalidated and that the TLB is flushed. What we want to achieve in all cases is that we cannot end up with a pin on an anonymous page that may be shared, because such pins would be unreliable and could result in memory corruptions when the mapped page and the pin go out of sync due to a write fault. That TLB flush handling was inspired by an outdated comment in mm/ksm.c:write_protect_page(), which similarly required the TLB flush in the past to synchronize with GUP-fast. However, ever since general RCU GUP fast was introduced in commit 2667f50e ("mm: introduce a general RCU get_user_pages_fast()"), a TLB flush is no longer sufficient to handle concurrent GUP-fast in all cases -- it only handles traditional IPI-based GUP-fast correctly. Peter Xu (thankfully) questioned whether that TLB flush is really required. On architectures that send an IPI broadcast on TLB flush, it works as expected. To synchronize with RCU GUP-fast properly, we're conceptually fine, however, we have to enforce a certain memory order and are missing memory barriers. Let's document that, avoid the TLB flush where possible and use proper explicit memory barriers where required. We shouldn't really care about the additional memory barriers here, as we're not on extremely hot paths -- and we're getting rid of some TLB flushes. We use a smp_mb() pair for handling concurrent pinning and a smp_rmb()/smp_wmb() pair for handling the corner case of only temporary PTE changes but permanent PageAnonExclusive changes. One extreme example, whereby GUP-fast takes a R/O pin and KSM wants to convert an exclusive anonymous page to a KSM page, and that page is already mapped write-protected (-> no PTE change) would be: Thread 0 (KSM) Thread 1 (GUP-fast) (B1) Read the PTE # (B2) skipped without FOLL_WRITE (A1) Clear PTE smp_mb() (A2) Check pinned (B3) Pin the mapped page smp_mb() (A3) Clear PageAnonExclusive smp_wmb() (A4) Restore PTE (B4) Check if the PTE changed smp_rmb() (B5) Check PageAnonExclusive Thread 1 will properly detect that PageAnonExclusive was cleared and back off. Note that we don't need a memory barrier between checking if the page is pinned and clearing PageAnonExclusive, because stores are not speculated. The possible issues due to reordering are of theoretical nature so far and attempts to reproduce the race failed. Especially the "no PTE change" case isn't the common case, because we'd need an exclusive anonymous page that's mapped R/O and the PTE is clean in KSM code -- and using KSM with page pinning isn't extremely common. Further, the clear+TLB flush we used for now implies a memory barrier. So the problematic missing part should be the missing memory barrier after pinning but before checking if the PTE changed. Link: https://lkml.kernel.org/r/20220901083559.67446-1-david@redhat.com Fixes: 6c287605 ("mm: remember exclusively mapped anonymous pages with PG_anon_exclusive") Signed-off-by:
David Hildenbrand <david@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Nadav Amit <namit@vmware.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Parri <parri.andrea@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Christoph von Recklinghausen <crecklin@redhat.com> Cc: Don Dutile <ddutile@redhat.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Christophe JAILLET authored
Use 'percpu_ref_tryget_live_rcu()' instead of 'percpu_ref_tryget_live()' to save a few cycles when it is known that the rcu lock is already taken/released. Link: https://lkml.kernel.org/r/9ef1562a1975371360f3e263856e9f1c5749b656.1662136782.git.christophe.jaillet@wanadoo.frSigned-off-by:
Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by:
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Kefeng Wang authored
Drop unneed comment and blank, adjust the variable, and the most important is to delete BUG_ON(). The page passed is always buddy page into __isolate_free_page() from compaction, page_isolation and page_reporting, and the caller also check the return, BUG_ON() is a too drastic measure, remove it. Link: https://lkml.kernel.org/r/20220901015043.189276-1-wangkefeng.wang@huawei.comSigned-off-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Signed-off-by:
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Liu Shixin authored
No caller cares about the return value of create_object(), so make it return void. Link: https://lkml.kernel.org/r/20220901023007.3471887-1-liushixin2@huawei.comSigned-off-by:
Liu Shixin <liushixin2@huawei.com> Acked-by:
Catalin Marinas <catalin.marinas@arm.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by:
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Tarun Sahu authored
Commit d2d6cba5d6623 ("selftest: vm: remove orphaned references to local_config.{h,mk}") took care of removing orphaned references. This commit removes local_config from .gitignore. Parent patch commit 69007f156ba ("Kselftests: remove support of libhugetlbfs from kselftests") Link: https://lkml.kernel.org/r/20220901092315.33619-1-tsahu@linux.ibm.comSigned-off-by:Tarun Sahu <tsahu@linux.ibm.com> Reviewed-by:
Axel Rasmussen <axelrasmussen@google.com> Signed-off-by:
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Miaohe Lin authored
If CONFIG_SYSFS and CONFIG_SYSCTL are both undefined, hugetlb doesn't work now as there's no way to set max huge pages. Make sure at least one of the above configs is defined to make hugetlb works as expected. Link: https://lkml.kernel.org/r/20220901120030.63318-11-linmiaohe@huawei.comSigned-off-by:
Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by:
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Miaohe Lin authored
When code reaches here, invalid page would have been accessed if huge pte is none. So this BUG_ON(huge_pte_none()) is meaningless. Remove it. Link: https://lkml.kernel.org/r/20220901120030.63318-10-linmiaohe@huawei.comSigned-off-by:
Muchun Song <songmuchun@bytedance.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by:
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Miaohe Lin authored
The SetHPageVmemmapOptimized() called here seems unnecessary as it's assumed to be set when calling this function. But it's indeed cleared by above set_page_private(page, 0). Add a comment to avoid possible future confusion. Link: https://lkml.kernel.org/r/20220901120030.63318-9-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
Fold hugetlbfs_pagecache_page() into its sole caller to remove some duplicated code. No functional change intended. Link: https://lkml.kernel.org/r/20220901120030.63318-8-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
We can pass NULL to kobj_to_hstate() directly when nid is unused to simplify the code. No functional change intended. Link: https://lkml.kernel.org/r/20220901120030.63318-7-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
Use helper huge_pte_lock and pmd_lock to simplify the code. No functional change intended. Link: https://lkml.kernel.org/r/20220901120030.63318-6-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
It's better to use sizeof() to get the array size instead of manual calculation. Minor readability improvement. Link: https://lkml.kernel.org/r/20220901120030.63318-5-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
Use LIST_HEAD() directly to define a list head to simplify the code. No functional change intended. Link: https://lkml.kernel.org/r/20220901120030.63318-4-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
Use helper macro SZ_1K to do the size conversion to make code more consistent in this file. Minor readability improvement. Link: https://lkml.kernel.org/r/20220901120030.63318-3-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
Patch series "A few cleanup patches for hugetlb", v2. This series contains a few cleanup patches to use helper functions to simplify the codes, remove unneeded nid parameter and so on. More details can be found in the respective changelogs. This patch (of 10): Make hugetlb_cma_check() static as it's only used inside mm/hugetlb.c. Link: https://lkml.kernel.org/r/20220901120030.63318-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220901120030.63318-2-linmiaohe@huawei.comSigned-off-by:
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Zhang Yi authored
bh_submit_read() has no user anymore, just remove it. Link: https://lkml.kernel.org/r/20220901133505.2510834-15-yi.zhang@huawei.comSigned-off-by:
Zhang Yi <yi.zhang@huawei.com> Reviewed-by:
Jan Kara <jack@suse.cz> Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Zhang Yi authored
bh_submit_read() and the uptodate check logic in bh_uptodate_or_lock() has been integrated in bh_read() helper, so switch to use it directly. Link: https://lkml.kernel.org/r/20220901133505.2510834-14-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
Now that all ll_rw_block() users has been replaced to new safe helpers, we just remove it here. Link: https://lkml.kernel.org/r/20220901133505.2510834-13-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() if the buffer has been locked by others. So stop using ll_rw_block() in ufs. Link: https://lkml.kernel.org/r/20220901133505.2510834-12-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() if the buffer has been locked by others. So stop using ll_rw_block(). We also switch to new bh_readahead_batch() helper for the buffer array readahead path. Link: https://lkml.kernel.org/r/20220901133505.2510834-11-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read/write path because it cannot guarantee that submitting read/write IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() in read path if the buffer has been locked by others. So stop using ll_rw_block() in reiserfs. We also switch to new bh_readahead_batch() helper for the buffer array readahead path. Link: https://lkml.kernel.org/r/20220901133505.2510834-10-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() if the buffer has been locked by others. So stop using ll_rw_block() in ocfs2. Link: https://lkml.kernel.org/r/20220901133505.2510834-9-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() if the buffer has been locked by others. So stop using ll_rw_block() in ntfs_get_block_vbo(). Link: https://lkml.kernel.org/r/20220901133505.2510834-8-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() if the buffer has been locked by others. So stop using ll_rw_block() in journal_get_superblock(). We also switch to new bh_readahead_batch() for the buffer array readahead path. Link: https://lkml.kernel.org/r/20220901133505.2510834-7-yi.zhang@huawei.comSigned-off-by:
Theodore Ts'o <tytso@mit.edu> Reviewed-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO return from zisofs_uncompress_block() if he buffer has been locked by others. So stop using ll_rw_block(), switch to sync helper instead. Link: https://lkml.kernel.org/r/20220901133505.2510834-6-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that always submitting read IO if the buffer has been locked, so stop using it. We also switch to new bh_readahead() helper for the readahead path. Link: https://lkml.kernel.org/r/20220901133505.2510834-5-yi.zhang@huawei.comSigned-off-by:
Andreas Gruenbacher <agruenba@redhat.com> Reviewed-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync IO path because it skip buffers which has been locked by others, it could lead to false positive EIO when submitting read IO. So stop using ll_rw_block(), switch to use new helpers which could guarantee buffer locked and submit IO if needed. Link: https://lkml.kernel.org/r/20220901133505.2510834-4-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
Current ll_rw_block() helper is fragile because it assumes that locked buffer means it's under IO which is submitted by some other who holds the lock, it skip buffer if it failed to get the lock, so it's only safe on the readahead path. Unfortunately, now that most filesystems still use this helper mistakenly on the sync metadata read path. There is no guarantee that the one who holds the buffer lock always submit IO (e.g. buffer_migrate_folio_norefs() after commit 88dbcbb3 ("blkdev: avoid migration stalls for blkdev pages"), it could lead to false positive -EIO when submitting reading IO. This patch add some friendly buffer read helpers to prepare replacing ll_rw_block() and similar calls. We can only call bh_readahead_[] helpers for the readahead paths. Link: https://lkml.kernel.org/r/20220901133505.2510834-3-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
Patch series "fs/buffer: remove ll_rw_block()", v2. ll_rw_block() will skip locked buffer before submitting IO, it assumes that locked buffer means it is under IO. This assumption is not always true because we cannot guarantee every buffer lock path would submit IO. After commit 88dbcbb3 ("blkdev: avoid migration stalls for blkdev pages"), buffer_migrate_folio_norefs() becomes one exceptional case, and there may be others. So ll_rw_block() is not safe on the sync read path, we could get false positive EIO return value when filesystem reading metadata. It seems that it could be only used on the readahead path. Unfortunately, many filesystem misuse the ll_rw_block() on the sync read path. This patch set just remove ll_rw_block() and add new friendly helpers, which could prevent false positive EIO on the read metadata path. Thanks for the suggestion from Jan, the original discussion is at [1]. patch 1: remove unused helpers in fs/buffer.c patch 2: add new bh_read_[*] helpers patch 3-11: remove all ll_rw_block() calls in filesystems patch 12-14: do some leftover cleanups. [1]. https://lore.kernel.org/linux-mm/20220825080146.2021641-1-chengzhihao1@huawei.com/ This patch (of 14): No one use __breadahead_gfp() and sb_breadahead_unmovable() any more, remove them. Link: https://lkml.kernel.org/r/20220901133505.2510834-1-yi.zhang@huawei.com Link: https://lkml.kernel.org/r/20220901133505.2510834-2-yi.zhang@huawei.comSigned-off-by:
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Song Liu authored
find_vmap_lowest_match() is now able to handle different roots. With DEBUG_AUGMENT_LOWEST_MATCH_CHECK enabled as: : --- a/mm/vmalloc.c : +++ b/mm/vmalloc.c : @@ -713,7 +713,7 @@ EXPORT_SYMBOL(vmalloc_to_pfn); : /*** Global kva allocator ***/ : : -#define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0 : +#define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 1 compilation failed as: mm/vmalloc.c: In function 'find_vmap_lowest_match_check': mm/vmalloc.c:1328:32: warning: passing argument 1 of 'find_vmap_lowest_match' makes pointer from integer without a cast [-Wint-conversion] 1328 | va_1 = find_vmap_lowest_match(size, align, vstart, false); | ^~~~ | | | long unsigned int mm/vmalloc.c:1236:40: note: expected 'struct rb_root *' but argument is of type 'long unsigned int' 1236 | find_vmap_lowest_match(struct rb_root *root, unsigned long size, | ~~~~~~~~~~~~~~~~^~~~ mm/vmalloc.c:1328:9: error: too few arguments to function 'find_vmap_lowest_match' 1328 | va_1 = find_vmap_lowest_match(size, align, vstart, false); | ^~~~~~~~~~~~~~~~~~~~~~ mm/vmalloc.c:1236:1: note: declared here 1236 | find_vmap_lowest_match(struct rb_root *root, unsigned long size, | ^~~~~~~~~~~~~~~~~~~~~~ Extend find_vmap_lowest_match_check() and find_vmap_lowest_linear_match() with extra arguments to fix this. Link: https://lkml.kernel.org/r/20220906060548.1127396-1-song@kernel.org Link: https://lkml.kernel.org/r/20220831052734.3423079-1-song@kernel.org Fixes: f9863be4 ("mm/vmalloc: extend __alloc_vmap_area() with extra arguments") Signed-off-by:Song Liu <song@kernel.org> Reviewed-by:
Baoquan He <bhe@redhat.com> Reviewed-by:
Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by:
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Alistair Popple authored
Commit ab09243a ("mm/migrate.c: remove MIGRATE_PFN_LOCKED") changed the way trylock_page() in migrate_vma_collect_pmd() works without updating the comment. Reword the comment to be less misleading and a better reflection of what happens. Link: https://lkml.kernel.org/r/20220830020138.497063-1-apopple@nvidia.com Fixes: ab09243a ("mm/migrate.c: remove MIGRATE_PFN_LOCKED") Signed-off-by:
Alistair Popple <apopple@nvidia.com> Reported-by:
Peter Xu <peterx@redhat.com> Acked-by:
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zezuo authored
The gfp_flags parameter is not used in rmqueue_pcplist, so directly delete this parameter. Link: https://lkml.kernel.org/r/20220831013404.3360714-1-zuoze1@huawei.comSigned-off-by:
zezuo <zuoze1@huawei.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by:
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Kaixu Xia authored
We can get the hotness value from damon_hot_score() directly in damon_pageout_score() function and improve the code readability. Link: https://lkml.kernel.org/r/1661766366-20998-1-git-send-email-kaixuxia@tencent.comSigned-off-by:
Kaixu Xia <kaixuxia@tencent.com> Reviewed-by:
SeongJae Park <sj@kernel.org> Signed-off-by:
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Liu Shixin authored
Simplify code by removing redundant CONFIG_TRANSPARENT_HUGEPAGE judgment. No functional change. Link: https://lkml.kernel.org/r/20220829095125.3284567-1-liushixin2@huawei.comSigned-off-by:
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Liu Shixin authored
Simplify code of has_transparent_hugepage define by using IS_BUILTIN. No functional change. Link: https://lkml.kernel.org/r/20220829095709.3287462-1-liushixin2@huawei.comSigned-off-by:
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Kaixu Xia authored
The damon regions that belong to the same damon target have the same 'struct mm_struct *mm', so it's unnecessary to compare the mm and last_mm objects among the damon regions in one damon target when checking accesses. But the check is necessary when the target changed in '__damon_va_check_accesses()', so we can simplify the whole operation by using the bool 'same_target' to indicate whether the target changed. Link: https://lkml.kernel.org/r/1661590971-20893-3-git-send-email-kaixuxia@tencent.comSigned-off-by:
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Kaixu Xia authored
Patch series "mm/damon: Simplify the damon regions access check", v2. This patchset simplifies the operations when checking the damon regions accesses. This patch (of 2): The parameter 'struct damon_ctx *ctx' isn't used in the functions __damon_{p,v}a_check_access(), so we can remove it and simplify the parameter passing. Link: https://lkml.kernel.org/r/1661590971-20893-1-git-send-email-kaixuxia@tencent.com Link: https://lkml.kernel.org/r/1661590971-20893-2-git-send-email-kaixuxia@tencent.comSigned-off-by: -
Kefeng Wang authored
kswapd_run/stop() will set pgdat->kswapd to NULL, which could race with kswapd_is_running() in kcompactd(), kswapd_run/stop() kcompactd() kswapd_is_running() pgdat->kswapd // error or nomal ptr verify pgdat->kswapd // load non-NULL pgdat->kswapd pgdat->kswapd = NULL task_is_running(pgdat->kswapd) // Null pointer derefence KASAN reports the null-ptr-deref shown below, vmscan: Failed to start kswapd on node 0 ... BUG: KASAN: null-ptr-deref in kcompactd+0x440/0x504 Read of size 8 at addr 0000000000000024 by task kcompactd0/37 CPU: 0 PID: 37 Comm: kcompactd0 Kdump: loaded Tainted: G OE 5.10.60 #1 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: dump_backtrace+0x0/0x394 show_stack+0x34/0x4c dump_stack+0x158/0x1e4 __kasan_report+0x138/0x140 kasan_report+0x44/0xdc __asan_load8+0x94/0xd0 kcompactd+0x440/0x504 kthread+0x1a4/0x1f0 ret_from_fork+0x10/0x18 At present kswapd/kcompactd_run() and kswapd/kcompactd_stop() are protected by mem_hotplug_begin/done(), but without kcompactd(). There is no need to involve memory hotplug lock in kcompactd(), so let's add a new mutex to protect pgdat->kswapd accesses. Also, because the kcompactd task will check the state of kswapd task, it's better to call kcompactd_stop() before kswapd_stop() to reduce lock conflicts. [akpm@linux-foundation.org: add comments] Link: https://lkml.kernel.org/r/20220827111959.186838-1-wangkefeng.wang@huawei.comSigned-off-by: -
Kefeng Wang authored
Directly check state of struct memory_block, no need a single function. Link: https://lkml.kernel.org/r/20220827112043.187028-1-wangkefeng.wang@huawei.comSigned-off-by:
Oscar Salvador <osalvador@suse.de> Reviewed-by:
Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by:
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Vishal Moola (Oracle) authored
All callers of find_get_pages_contig() have been removed, so it is no longer needed. Link: https://lkml.kernel.org/r/20220824004023.77310-8-vishal.moola@gmail.comSigned-off-by:
Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <clm@fb.com> Cc: David Sterba <dsterba@suse.com> Cc: David Sterba <dsterb@suse.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com> Signed-off-by:
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