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[90.235.2.22]) by smtp.gmail.com with ESMTPSA id l3-20020a2e9083000000b002da6fb7ce36sm1425059ljg.135.2024.04.22.02.40.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Apr 2024 02:40:59 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Mon, 22 Apr 2024 11:40:56 +0200 To: hailong.liu@oppo.com Cc: akpm@linux-foundation.org, urezki@gmail.com, hch@infradead.org, lstoakes@gmail.com, 21cnbao@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2] mm/vmalloc: fix return value of vb_alloc if size is 0. Message-ID: References: <20240419101643.11534-1-hailong.liu@oppo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240419101643.11534-1-hailong.liu@oppo.com> X-Stat-Signature: 7uwdazpam3rjw8bad9ub8pkptoou39by X-Rspamd-Queue-Id: 20E7B160002 X-Rspamd-Server: rspam06 X-Rspam-User: X-HE-Tag: 1713778861-328381 X-HE-Meta: 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 pk6hGLNM 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 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 Fri, Apr 19, 2024 at 06:16:43PM +0800, hailong.liu@oppo.com wrote: > From: "Hailong.Liu" > > vm_map_ram check return value of vb_alloc by IS_ERR. if > vm_map_ram(page, 0, 0) , vb_alloc(0, GFP_KERNEL) would return NULL > which cause kernel panic by vmap_pages_range_noflush。fix this by > return ERR_PTR(-EINVAL) if size is 0. > > Signed-off-by: Hailong.Liu > --- > Changes since v1 [1]: > - Return ERR_PTR(-EINVAL) or not check IS_ERR_OR_NULL > > BTW, Barry suggests me that if count is 0, return directly, in my > opinion, change return value is more resonable. > > [1] https://lore.kernel.org/all/84d7cd03-1cf8-401a-8edf-2524db0bd6d5@oppo.com/ > > mm/vmalloc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index a3fedb3ee0db..c430a999805b 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2173,7 +2173,7 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask) > * get_order(0) returns funny result. Just warn and terminate > * early. > */ > - return NULL; > + return ERR_PTR(-EINVAL); > } > order = get_order(size); > > -- > 2.34.1 > Reviewed-by: Uladzislau Rezki (Sony) -- Uladzislau Rezki