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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=1Eo+gSlfTRvBWoE7OSsEw0r9zCTwxyud4BviRS8WC6p3jYb+6851KPHdtVEZaSN4/ cMIs4aDm31In029+81likJL1RxCk2mtUfPSckNj8SuKNYZGxwyCgBTIIH2d9dEk5ey IEkBRge+lljE2AdZMG6chetZ1eSkgKrVntzwfIHY= Date: Thu, 3 Jul 2025 12:06:02 +0200 From: Greg KH To: Jeongjun Park Cc: stable@vger.kernel.org, urezki@gmail.com, akpm@linux-foundation.org, edumazet@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 6.15.y] mm/vmalloc: fix data race in show_numa_info() Message-ID: <2025070322-front-purchase-b66f@gregkh> References: <20250702153312.351080-1-aha310510@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250702153312.351080-1-aha310510@gmail.com> X-Stat-Signature: qq561isx38g9j7dr7tgot81nwpwaz5eg X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: E09A31C0002 X-Rspam-User: X-HE-Tag: 1751537165-602316 X-HE-Meta: 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 oEJUgSMJ CIMUoz7LknhoYMt1gtX2WtBmCRULX3r8NHfuqpgbCOu5Wtx3rTKO3oE7Qp6xN12URmZvxHtkDSTUk9k7B2e3znHq7cwJJ2dcg7VAMTv2DbpQUTnqDQ1AZHEezBOwpRqFXc7jbNra4jbe42qMu/kjkucmUnWT1EDlHqWuSigUYIK5vtDwGGF/UTDnvvfYkMQsvjbG2T2N6lGdJjCqB5izT0CiXQv5BxVbEFGu5mR+IPFl0kCwLqJDVjR6Aqahi7tTNc8mh7MnFSFJa17cJ2d464i3V0GRW9cfPD1JzaG0f9a+jA/MxuFRnv/1Fm72fHNKW61HhF03vPoeIHMPQckaqkjjxpVOVinh9VzliChm8DG2qkjDKlwQUfwlnOB6/yyOWahG3aBY+Y4BpNGYuI8jKaZSoWLbvdUmS4bxkT0xViCT8dRbIEjMC3WnL5oUnROPJFecJx5VfMnpo+xw= 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: On Thu, Jul 03, 2025 at 12:33:12AM +0900, Jeongjun Park wrote: > commit 5c5f0468d172ddec2e333d738d2a1f85402cf0bc upstream. > > The following data-race was found in show_numa_info(): > > ================================================================== > BUG: KCSAN: data-race in vmalloc_info_show / vmalloc_info_show > > read to 0xffff88800971fe30 of 4 bytes by task 8289 on cpu 0: > show_numa_info mm/vmalloc.c:4936 [inline] > vmalloc_info_show+0x5a8/0x7e0 mm/vmalloc.c:5016 > seq_read_iter+0x373/0xb40 fs/seq_file.c:230 > proc_reg_read_iter+0x11e/0x170 fs/proc/inode.c:299 > .... > > write to 0xffff88800971fe30 of 4 bytes by task 8287 on cpu 1: > show_numa_info mm/vmalloc.c:4934 [inline] > vmalloc_info_show+0x38f/0x7e0 mm/vmalloc.c:5016 > seq_read_iter+0x373/0xb40 fs/seq_file.c:230 > proc_reg_read_iter+0x11e/0x170 fs/proc/inode.c:299 > .... > > value changed: 0x0000008f -> 0x00000000 > ================================================================== > > According to this report,there is a read/write data-race because > m->private is accessible to multiple CPUs. To fix this, instead of > allocating the heap in proc_vmalloc_init() and passing the heap address to > m->private, vmalloc_info_show() should allocate the heap. > > Link: https://lkml.kernel.org/r/20250508165620.15321-1-aha310510@gmail.com > Fixes: 8e1d743 ("mm: vmalloc: support multiple nodes in vmallocinfo") Why did you change this line? > Signed-off-by: Jeongjun Park > Suggested-by: Eric Dumazet > Suggested-by: Andrew Morton > Reviewed-by: "Uladzislau Rezki (Sony)" > Signed-off-by: Andrew Morton > --- > mm/vmalloc.c | 63 +++++++++++++++++++++++++++++----------------------- > 1 file changed, 35 insertions(+), 28 deletions(-) Please document what you changed from the original version, as this does not match what is in Linus's tree. thanks, greg k-h