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Mon, 24 Feb 2025 21:59:27 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.22.65.50]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C092D180035F; Mon, 24 Feb 2025 21:59:25 +0000 (UTC) From: Luiz Capitulino To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, david@redhat.com, yuzhao@google.com, pasha.tatashin@soleen.com Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, muchun.song@linux.dev, luizcap@redhat.com Subject: [PATCH v2 4/4] mm: page_owner: use new iteration API Date: Mon, 24 Feb 2025 16:59:08 -0500 Message-ID: In-Reply-To: References: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Rspam-User: X-Rspamd-Queue-Id: A3CE720003 X-Rspamd-Server: rspam12 X-Stat-Signature: chkcjau4y3sie5s6fh56pyd4g53gosuk X-HE-Tag: 1740434374-441928 X-HE-Meta: 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 XeXI3zsQ TJgICsIuYxvgshBrSOY5KpwLU/dz/HP+sX7efc22aRrf7b19cYkPsO5wPievmpfXUu789sCkiJJJGzz2fSoPsB33tkK1T4L73tD3vKT8UpI1hRWDzoyAzWFsEduWRNHzryzFFnLrBnwARdRqWiz3tHIBJ/KbZPVZpFigktipATAf+qD3g694yNLSdZnN+alWyHNU7ixWhb7vkQDIdwEr/Npq7r97EIAnF9+QCenoyUjzWAWgvnvOAxTitFiEAb20tFpX27eFFavZ+QZroGcL1GRAvlRHp8PTOVL+7ezlhxRcVRIPjYXKAZ7sG8fGCTdryCM1SlViyPd4PVpqDLAlPUT1llhr68CL67TwJ9RgBWaT+jHAx8nl7M8X4AA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The page_ext_next() function assumes that page extension objects for a page order allocation always reside in the same memory section, which may not be true and could lead to crashes. Use the new page_ext iteration API instead. Fixes: cf54f310d0d3 ("mm/hugetlb: use __GFP_COMP for gigantic folios") Signed-off-by: Luiz Capitulino --- mm/page_owner.c | 61 +++++++++++++++++++++++-------------------------- 1 file changed, 29 insertions(+), 32 deletions(-) diff --git a/mm/page_owner.c b/mm/page_owner.c index 2d6360eaccbb6..c9d2c688eb981 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -229,17 +229,19 @@ static void dec_stack_record_count(depot_stack_handle_t handle, handle); } -static inline void __update_page_owner_handle(struct page_ext *page_ext, +static inline void __update_page_owner_handle(struct page *page, depot_stack_handle_t handle, unsigned short order, gfp_t gfp_mask, short last_migrate_reason, u64 ts_nsec, pid_t pid, pid_t tgid, char *comm) { - int i; + struct page_ext_iter iter; + struct page_ext *page_ext; struct page_owner *page_owner; - for (i = 0; i < (1 << order); i++) { + rcu_read_lock(); + for_each_page_ext(page, 1 << order, page_ext, iter) { page_owner = get_page_owner(page_ext); page_owner->handle = handle; page_owner->order = order; @@ -252,20 +254,22 @@ static inline void __update_page_owner_handle(struct page_ext *page_ext, sizeof(page_owner->comm)); __set_bit(PAGE_EXT_OWNER, &page_ext->flags); __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); - page_ext = page_ext_next(page_ext); } + rcu_read_unlock(); } -static inline void __update_page_owner_free_handle(struct page_ext *page_ext, +static inline void __update_page_owner_free_handle(struct page *page, depot_stack_handle_t handle, unsigned short order, pid_t pid, pid_t tgid, u64 free_ts_nsec) { - int i; + struct page_ext_iter iter; + struct page_ext *page_ext; struct page_owner *page_owner; - for (i = 0; i < (1 << order); i++) { + rcu_read_lock(); + for_each_page_ext(page, 1 << order, page_ext, iter) { page_owner = get_page_owner(page_ext); /* Only __reset_page_owner() wants to clear the bit */ if (handle) { @@ -275,8 +279,8 @@ static inline void __update_page_owner_free_handle(struct page_ext *page_ext, page_owner->free_ts_nsec = free_ts_nsec; page_owner->free_pid = current->pid; page_owner->free_tgid = current->tgid; - page_ext = page_ext_next(page_ext); } + rcu_read_unlock(); } void __reset_page_owner(struct page *page, unsigned short order) @@ -293,11 +297,11 @@ void __reset_page_owner(struct page *page, unsigned short order) page_owner = get_page_owner(page_ext); alloc_handle = page_owner->handle; + page_ext_put(page_ext); handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); - __update_page_owner_free_handle(page_ext, handle, order, current->pid, + __update_page_owner_free_handle(page, handle, order, current->pid, current->tgid, free_ts_nsec); - page_ext_put(page_ext); if (alloc_handle != early_handle) /* @@ -313,19 +317,13 @@ void __reset_page_owner(struct page *page, unsigned short order) noinline void __set_page_owner(struct page *page, unsigned short order, gfp_t gfp_mask) { - struct page_ext *page_ext; u64 ts_nsec = local_clock(); depot_stack_handle_t handle; handle = save_stack(gfp_mask); - - page_ext = page_ext_get(page); - if (unlikely(!page_ext)) - return; - __update_page_owner_handle(page_ext, handle, order, gfp_mask, -1, + __update_page_owner_handle(page, handle, order, gfp_mask, -1, ts_nsec, current->pid, current->tgid, current->comm); - page_ext_put(page_ext); inc_stack_record_count(handle, gfp_mask, 1 << order); } @@ -344,26 +342,24 @@ void __set_page_owner_migrate_reason(struct page *page, int reason) void __split_page_owner(struct page *page, int old_order, int new_order) { - int i; - struct page_ext *page_ext = page_ext_get(page); + struct page_ext_iter iter; + struct page_ext *page_ext; struct page_owner *page_owner; - if (unlikely(!page_ext)) - return; - - for (i = 0; i < (1 << old_order); i++) { + rcu_read_lock(); + for_each_page_ext(page, 1 << old_order, page_ext, iter) { page_owner = get_page_owner(page_ext); page_owner->order = new_order; - page_ext = page_ext_next(page_ext); } - page_ext_put(page_ext); + rcu_read_unlock(); } void __folio_copy_owner(struct folio *newfolio, struct folio *old) { - int i; struct page_ext *old_ext; struct page_ext *new_ext; + struct page_ext *page_ext; + struct page_ext_iter iter; struct page_owner *old_page_owner; struct page_owner *new_page_owner; depot_stack_handle_t migrate_handle; @@ -381,7 +377,7 @@ void __folio_copy_owner(struct folio *newfolio, struct folio *old) old_page_owner = get_page_owner(old_ext); new_page_owner = get_page_owner(new_ext); migrate_handle = new_page_owner->handle; - __update_page_owner_handle(new_ext, old_page_owner->handle, + __update_page_owner_handle(&newfolio->page, old_page_owner->handle, old_page_owner->order, old_page_owner->gfp_mask, old_page_owner->last_migrate_reason, old_page_owner->ts_nsec, old_page_owner->pid, @@ -391,7 +387,7 @@ void __folio_copy_owner(struct folio *newfolio, struct folio *old) * will be freed after migration. Keep them until then as they may be * useful. */ - __update_page_owner_free_handle(new_ext, 0, old_page_owner->order, + __update_page_owner_free_handle(&newfolio->page, 0, old_page_owner->order, old_page_owner->free_pid, old_page_owner->free_tgid, old_page_owner->free_ts_nsec); @@ -400,11 +396,12 @@ void __folio_copy_owner(struct folio *newfolio, struct folio *old) * for the new one and the old folio otherwise there will be an imbalance * when subtracting those pages from the stack. */ - for (i = 0; i < (1 << new_page_owner->order); i++) { + rcu_read_lock(); + for_each_page_ext(&old->page, 1 << new_page_owner->order, page_ext, iter) { + old_page_owner = get_page_owner(page_ext); old_page_owner->handle = migrate_handle; - old_ext = page_ext_next(old_ext); - old_page_owner = get_page_owner(old_ext); } + rcu_read_unlock(); page_ext_put(new_ext); page_ext_put(old_ext); @@ -813,7 +810,7 @@ static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) goto ext_put_continue; /* Found early allocated page */ - __update_page_owner_handle(page_ext, early_handle, 0, 0, + __update_page_owner_handle(page, early_handle, 0, 0, -1, local_clock(), current->pid, current->tgid, current->comm); count++;