Hi Daniel, [adding Ulf, Chris and Mike to the discussion] On 24.06.2014 11:48, Daniel Drake wrote: > sdhci_s3c_set_clock is called from sdhci_do_set_ios with interrupts > disabled, and this calls into sdhci_s3c_consider_clock(). > > The patch "mmc: sdhci-s3c: Cache bus clock rates" addressed some > scheduling while atomic in this function, but there are more issues > here, seen while testing 3.16-rc2 on exynos4412: > > BUG: sleeping function called from invalid context at kernel/locking/mutex.c:103 > in_atomic(): 1, irqs_disabled(): 128, pid: 75, name: mmcqd/0 > Preemption disabled at:[< (null)>] (null) > > CPU: 0 PID: 75 Comm: mmcqd/0 Not tainted 3.16.0-rc2-00028-ge9fe7eb-dirty #77 > [<c0016140>] (unwind_backtrace) from [<c0011e14>] (show_stack+0x10/0x14) > [<c0011e14>] (show_stack) from [<c05ce8a8>] (dump_stack+0x84/0xc4) > [<c05ce8a8>] (dump_stack) from [<c05d2de0>] (mutex_lock+0x1c/0x3c) > [<c05d2de0>] (mutex_lock) from [<c046214c>] (clk_prepare_lock+0x6c/0xf4) > [<c046214c>] (clk_prepare_lock) from [<c04625ac>] (clk_round_rate+0x10/0x2c) > [<c04625ac>] (clk_round_rate) from [<c0447628>] (sdhci_s3c_set_clock+0x4c/0x1e8) > [<c0447628>] (sdhci_s3c_set_clock) from [<c0447818>] > (sdhci_cmu_set_clock+0x54/0x140) > [<c0447818>] (sdhci_cmu_set_clock) from [<c0443a38>] > (sdhci_do_set_ios+0x138/0x58c) > [<c0443a38>] (sdhci_do_set_ios) from [<c0443864>] (sdhci_set_ios+0x28/0x34) > > clk_round_rate cannot be called here because it takes a mutex. > > sdhci_s3c_set_clock() also calls into clk_prepare_enable() which looks > like it could trigger this problem too. Apparently this is related to generic sdhci code calling .set_clock() under spin_lock_irqsave(). For reference, see sdhci_do_set_ios() and sdhci_tasklet_finish(). Chris, Ulf, any suggestions? Best regards, Tomasz -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
