From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [to-be-updated] mm-kmemleak-annotate-a-data-race-in-checksum.patch removed from -mm tree Date: Thu, 13 Feb 2020 19:06:52 -0800 Message-ID: <20200214030652.iHbK1xAdw%akpm@linux-foundation.org> References: <20200203173311.6269a8be06a05e5a4aa08a93@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:39888 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727604AbgBNDGy (ORCPT ); Thu, 13 Feb 2020 22:06:54 -0500 In-Reply-To: <20200203173311.6269a8be06a05e5a4aa08a93@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: cai@lca.pw, catalin.marinas@arm.com, elver@google.com, mm-commits@vger.kernel.org The patch titled Subject: mm/kmemleak.c: annotate a data race in checksum has been removed from the -mm tree. Its filename was mm-kmemleak-annotate-a-data-race-in-checksum.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: Qian Cai Subject: mm/kmemleak.c: annotate a data race in checksum The value of object->pointer could be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in crc32_le_base / do_raw_spin_lock write to 0xffffb0ea683a7d50 of 4 bytes by task 23575 on cpu 12: do_raw_spin_lock+0x114/0x200 debug_spin_lock_after at kernel/locking/spinlock_debug.c:91 (inlined by) do_raw_spin_lock at kernel/locking/spinlock_debug.c:115 _raw_spin_lock+0x40/0x50 __handle_mm_fault+0xa9e/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffffb0ea683a7d50 of 4 bytes by task 839 on cpu 60: crc32_le_base+0x67/0x350 crc32_le_base+0x67/0x350: crc32_body at lib/crc32.c:106 (inlined by) crc32_le_generic at lib/crc32.c:179 (inlined by) crc32_le at lib/crc32.c:197 kmemleak_scan+0x528/0xd90 update_checksum at mm/kmemleak.c:1172 (inlined by) kmemleak_scan at mm/kmemleak.c:1497 kmemleak_scan_thread+0xcc/0xfa kthread+0x1e0/0x200 ret_from_fork+0x27/0x50 Reported by Kernel Concurrency Sanitizer on: CPU: 60 PID: 839 Comm: kmemleak Tainted: G W L 5.5.0-next-20200210+ #3 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 crc32() will dereference object->pointer. If a shattered value was returned due to a data race, it will be corrected in the next scan. Thus, annotate it as an intentional data race using the data_race() macro. Link: http://lkml.kernel.org/r/1581438245-24391-1-git-send-email-cai@lca.pw Signed-off-by: Qian Cai Acked-by: Catalin Marinas Cc: Marco Elver Signed-off-by: Andrew Morton --- mm/kmemleak.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/mm/kmemleak.c~mm-kmemleak-annotate-a-data-race-in-checksum +++ a/mm/kmemleak.c @@ -1169,7 +1169,12 @@ static bool update_checksum(struct kmeml u32 old_csum = object->checksum; kasan_disable_current(); - object->checksum = crc32(0, (void *)object->pointer, object->size); + /* + * crc32() will dereference object->pointer. If an unstable value was + * returned due to a data race, it will be corrected in the next scan. + */ + object->checksum = data_race(crc32(0, (void *)object->pointer, + object->size)); kasan_enable_current(); return object->checksum != old_csum; _ Patches currently in -mm which might be from cai@lca.pw are mm-kmemleak-annotate-various-data-races-obj-ptr.patch mm-swapfile-fix-and-annotate-various-data-races.patch mm-page_counter-fix-various-data-races-at-memsw.patch mm-memcontrol-fix-a-data-race-in-scan-count.patch mm-list_lru-fix-a-data-race-in-list_lru_count_one.patch mm-mempool-fix-a-data-race-in-mempool_free.patch mm-util-annotate-an-data-race-at-vm_committed_as.patch mm-rmap-annotate-a-data-race-at-tlb_flush_batched.patch mm-frontswap-mark-various-intentional-data-races.patch mm-page_io-mark-various-intentional-data-races.patch mm-swap_state-mark-various-intentional-data-races.patch