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[82.243.161.21]) by smtp.gmail.com with ESMTPSA id d16sm22991983wrg.27.2019.12.16.03.21.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Dec 2019 03:21:48 -0800 (PST) References: <20191215114705.24401-1-repk@triplefau.lt> User-agent: mu4e 1.3.3; emacs 26.3 From: Jerome Brunet To: Martin Blumenstingl , Remi Pommarel Cc: Neil Armstrong , Stephen Boyd , Kevin Hilman , Michael Turquette , linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2] clk: meson: pll: Fix by 0 division in __pll_params_to_rate() In-reply-to: Date: Mon, 16 Dec 2019 12:21:47 +0100 Message-ID: <1jmubsbjn8.fsf@starbuckisacylon.baylibre.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 15 Dec 2019 at 21:34, Martin Blumenstingl wrote: > On Sun, Dec 15, 2019 at 12:39 PM Remi Pommarel wrote: >> >> Some meson pll registers can be initialized with 0 as N value, introducing >> the following division by 0 when computing rate : >> >> UBSAN: Undefined behaviour in drivers/clk/meson/clk-pll.c:75:9 >> division by zero >> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc3-608075-g86c9af8630e1-dirty #400 >> Call trace: >> dump_backtrace+0x0/0x1c0 >> show_stack+0x14/0x20 >> dump_stack+0xc4/0x100 >> ubsan_epilogue+0x14/0x68 >> __ubsan_handle_divrem_overflow+0x98/0xb8 >> __pll_params_to_rate+0xdc/0x140 >> meson_clk_pll_recalc_rate+0x278/0x3a0 >> __clk_register+0x7c8/0xbb0 >> devm_clk_hw_register+0x54/0xc0 >> meson_eeclkc_probe+0xf4/0x1a0 >> platform_drv_probe+0x54/0xd8 >> really_probe+0x16c/0x438 >> driver_probe_device+0xb0/0xf0 >> device_driver_attach+0x94/0xa0 >> __driver_attach+0x70/0x108 >> bus_for_each_dev+0xd8/0x128 >> driver_attach+0x30/0x40 >> bus_add_driver+0x1b0/0x2d8 >> driver_register+0xbc/0x1d0 >> __platform_driver_register+0x78/0x88 >> axg_driver_init+0x18/0x20 >> do_one_initcall+0xc8/0x24c >> kernel_init_freeable+0x2b0/0x344 >> kernel_init+0x10/0x128 >> ret_from_fork+0x10/0x18 >> >> This checks if N is null before doing the division. >> >> Fixes: 7a29a869434e ("clk: meson: Add support for Meson clock controller") >> Signed-off-by: Remi Pommarel > Reviewed-by: Martin Blumenstingl Applied with a slightly more detailed comment. Thx > > thank you for the patch Remi! > > > Martin