Hi Lukasz, On Tue, Feb 17, 2015 at 1:28 AM, Lukasz Majewski <l.majewski@xxxxxxxxxxx> wrote: > Hi Chanwoo, > >> Hi Lukasz, >> >> On Tue, Feb 17, 2015 at 12:06 AM, Lukasz Majewski >> <l.majewski@xxxxxxxxxxx> wrote: >> > Hi Chanwoo, >> > >> >> This patch fixes the NULL pointer exception during kernel booting. >> >> The thermal_zone _of_sensor_register() registers a sensor to DT >> >> thermal zone and then read the current temperature by '.get_temp' >> >> callback. The callback function of exynos thermal driver is >> >> exynos_get_temp() which must need the 'pdata' instance of >> >> exynos_tmu _platform_data structure. >> >> - exynos_get_temp() -> code_to_temp() -> Must need the 'pdata' >> >> instance >> >> >> >> But, exynos thermal driver is executed before getting the 'pdata' >> >> instance. To avoid the kernel panic, have to get the platform data >> >> by executing the exynos_map_dt_data() before calling >> >> thermal_zone_of_sensor_register() . >> > >> > I've already prepared patch for this (unfortunately it isn't yet >> > applied to mainline): >> > >> > "[PATCH] thermal: exynos: fix: Check if data->tmu_read callback is >> > present before read" >> > >> > http://www.spinics.net/lists/linux-samsung-soc/msg42245.html >> >> There is different issue between you patch and this patch. >> Your patch check the whether data->tmu_read is NULL or not. >> But, my patch check the pdata is NULL or not. > > I've tried to do the same previously. Please compare with: > [PATCH 1/2] thermal: exynos: Reorder exynos_map_dt_data() function > > http://www.spinics.net/lists/linux-samsung-soc/msg41308.html > > Unfortunately, Abhilash found some issues with this code, so I've > looked into different solution. OK. > > > However, I didn't need to move pdata = data->pdata; Hence, I wonder why > it need to be reordered. Are you using Exynos3250 based device? I think it is necessary to prevent kernel panic. We can check this issue by analyzing the thermal_zone_of_sensor_register() as following issue: of_thermal_get_temp() executes the exynos_get_temp() finally. And exynos_get_temp() function must need the 'pdata' instance. The 'pdata' instance is initialized on exynos_map_dt_data(). If exynos_tmu driver executes the exynos_map_dt_data() after thermal_zone_of_sensor_register(), this issue happen again. [ 4211.945315] [<ffffffc0004de6d8>] of_thermal_get_temp+0x1c/0x30 [ 4211.951132] [<ffffffc0004db86c>] thermal_zone_get_temp+0x48/0x7c [ 4211.957118] [<ffffffc0004dd278>] thermal_zone_device_update+0x20/0x110 [ 4211.963627] [<ffffffc0004de9c8>] of_thermal_set_mode+0x44/0x68 [ 4211.969443] [<ffffffc0004decb8>] thermal_zone_of_sensor_register+0x15c/0x1d8 I tested it on Exynos5433 based device. > > >> >> > >> > Does applying this patch help? >> > >> > BTW: How can I reproduce this error? Could you point me the SHA1 and >> > repository? >> >> I used your patch-set of linux-soc-thermal.git (branch: next). So I >> applied you patchiest on Linux 3.19 for test. >> - >> https://git.kernel.org/cgit/linux/kernel/git/evalenti/linux-soc-thermal.git/log/?h=next > > Is there any special .config? There is no special configuration. I tested this patch with CPUFREQ for cooling device. > > May I ask about the target platform? > I will look closely on this problem tomorrow. OK. Best Regards, Chanwoo Choi -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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