From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758550AbbBFMex (ORCPT ); Fri, 6 Feb 2015 07:34:53 -0500 Received: from bhuna.collabora.co.uk ([93.93.135.160]:59219 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754711AbbBFMew (ORCPT ); Fri, 6 Feb 2015 07:34:52 -0500 Message-ID: <54D4B4E5.6020003@collabora.com> Date: Fri, 06 Feb 2015 13:34:45 +0100 From: Tomeu Vizoso User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Stephen Boyd , Mike Turquette CC: linux-kernel@vger.kernel.org, Sylwester Nawrocki , Alban Browaeys Subject: Re: [PATCH v2] clkdev: Always allocate a struct clk and call __clk_get() w/ CCF References: <1423186850-32547-1-git-send-email-sboyd@codeaurora.org> In-Reply-To: <1423186850-32547-1-git-send-email-sboyd@codeaurora.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/06/2015 02:40 AM, Stephen Boyd wrote: > of_clk_get_by_clkspec() returns a struct clk pointer but it > doesn't create a new handle for the consumers when we're using > the common clock framework. Instead it just returns whatever the > clk provider hands out. When the consumers go to call clk_put() > we get an Oops. > > Unable to handle kernel paging request at virtual address 00200200 > pgd = c0004000 > [00200200] *pgd=00000000 > Internal error: Oops: 805 [#1] PREEMPT SMP ARM > Modules linked in: > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.19.0-rc1-00104-ga251361a-dirty #992 > Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) > task: ee00b000 ti: ee088000 task.ti: ee088000 > PC is at __clk_put+0x24/0xd0 > LR is at clk_prepare_lock+0xc/0xec > pc : [] lr : [] psr: 20000153 > sp : ee089de8 ip : 00000000 fp : 00000000 > r10: ee02f480 r9 : 00000001 r8 : 00000000 > r7 : ee031cc0 r6 : ee089e08 r5 : 00000000 r4 : ee02f480 > r3 : 00100100 r2 : 00200200 r1 : 0000091e r0 : 00000001 > Flags: nzCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment kernel > Control: 10c5387d Table: 4000404a DAC: 00000015 > Process swapper/0 (pid: 1, stack limit = 0xee088238) > Stack: (0xee089de8 to 0xee08a000) > 9de0: ee7c8f14 c03f0ec8 ee089e08 00000000 c0718dc8 00000001 > 9e00: 00000000 c04ee0f0 ee7e0844 00000001 00000181 c04edb58 ee2bd320 00000000 > 9e20: 00000000 c011dc5c ee16a1e0 00000000 00000000 c0718dc8 ee16a1e0 ee2bd1e0 > 9e40: c0641740 ee16a1e0 00000000 ee2bd320 c0718dc8 ee1d3e10 ee1d3e10 00000000 > 9e60: c0769a88 00000000 c0718dc8 00000000 00000000 c02c3124 c02c310c ee1d3e10 > 9e80: c07b4eec 00000000 c0769a88 c02c1d0c ee1d3e10 c0769a88 ee1d3e44 00000000 > 9ea0: c07091dc c02c1eb8 00000000 c0769a88 c02c1e2c c02c0544 ee005478 ee1676c0 > 9ec0: c0769a88 ee3a4e80 c0760ce8 c02c150c c0669b90 c0769a88 c0746cd8 c0769a88 > 9ee0: c0746cd8 ee2bc4c0 c0778c00 c02c24e0 00000000 c0746cd8 c0746cd8 c07091f0 > 9f00: 00000000 c0008944 c04f405c 00000025 ee00b000 60000153 c074ab00 00000000 > 9f20: 00000000 c074ab90 60000153 00000000 ef7fca5d c050860c 000000b6 c0036b88 > 9f40: c065ecc4 c06bc728 00000006 00000006 c074ab30 ef7fca40 c0739bdc 00000006 > 9f60: c0718dbc c0778c00 000000b6 c0718dc8 c06ed598 c06edd64 00000006 00000006 > 9f80: c06ed598 c003b438 00000000 c04e64f4 00000000 00000000 00000000 00000000 > 9fa0: 00000000 c04e64fc 00000000 c000e838 00000000 00000000 00000000 00000000 > 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 c0c0c0c0 c0c0c0c0 > [] (__clk_put) from [] (of_clk_set_defaults+0xe0/0x2c0) > [] (of_clk_set_defaults) from [] (platform_drv_probe+0x18/0xa4) > [] (platform_drv_probe) from [] (driver_probe_device+0x10c/0x22c) > [] (driver_probe_device) from [] (__driver_attach+0x8c/0x90) > [] (__driver_attach) from [] (bus_for_each_dev+0x54/0x88) > [] (bus_for_each_dev) from [] (bus_add_driver+0xd4/0x1d0) > [] (bus_add_driver) from [] (driver_register+0x78/0xf4) > [] (driver_register) from [] (fimc_md_init+0x14/0x30) > [] (fimc_md_init) from [] (do_one_initcall+0x80/0x1d0) > [] (do_one_initcall) from [] (kernel_init_freeable+0x108/0x1d4) > [] (kernel_init_freeable) from [] (kernel_init+0x8/0xec) > [] (kernel_init) from [] (ret_from_fork+0x14/0x3c) > Code: ebfff4ae e5943014 e5942018 e3530000 (e5823000) > > Let's create a per-user handle here so that clk_put() can > properly unlink it and free the handle. Now that we allocate a > clk structure here we need to free it if __clk_get() fails so > bury the __clk_get() call in __of_clk_get_from_provider(). We > need to handle the same problem in clk_get_sys() so export > __clk_free_clk() to clkdev.c and do the same thing, except let's > do some more inline functions to make this code #ifdef free. > > This fixes the above crash, properly calls __clk_get() when > of_clk_get_from_provider() is called, and cleans up the clk > structure on the error path of clk_get_sys(). > > Fixes: 035a61c314eb "clk: Make clk API return per-user struct clk instances" > Reported-by: Sylwester Nawrocki > Reported-by: Alban Browaeys > Cc: Tomeu Vizoso > Signed-off-by: Stephen Boyd > --- > drivers/clk/clk.c | 18 +++++++++++++---- > drivers/clk/clk.h | 19 +++++++++++++++++- > drivers/clk/clkdev.c | 56 ++++++++++++++++++++++------------------------------ > 3 files changed, 56 insertions(+), 37 deletions(-) > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > index 113456030d66..5469d7714f5d 100644 > --- a/drivers/clk/clk.c > +++ b/drivers/clk/clk.c [snip] > @@ -209,17 +205,13 @@ struct clk *clk_get_sys(const char *dev_id, const char *con_id) > if (!cl) > goto out; > > - if (!__clk_get(cl->clk)) { > + clk = __clk_create_clk(__clk_get_hw(cl->clk), dev_id, con_id); We need to check for clk being an error either here or in __clk_get because __clk_create_clk can return -ENOMEM. > + if (!__clk_get(clk)) { > + __clk_free_clk(clk); > cl = NULL; > goto out; > } > > -#if defined(CONFIG_COMMON_CLK) > - clk = __clk_create_clk(__clk_get_hw(cl->clk), dev_id, con_id); > -#else > - clk = cl->clk; > -#endif > - > out: > mutex_unlock(&clocks_mutex); Otherwise it looks good to me. Reviewed-by: Tomeu Vizoso Thanks, Tomeu