Hi Seung-Woo, On 06/08/2016 01:07 PM, Seung-Woo Kim wrote: > This patch removes following UBSAN warnings in dw_mci_setup_bus(). > The warnings are caused because of shift with more than 31 on 32 > bit variable, so this patch fixes to shift only for less than 32. > > UBSAN: Undefined behaviour in drivers/mmc/host/dw_mmc.c:1102:14 > shift exponent 250 is too large for 32-bit type 'unsigned int' > Call trace: > [<ffffff90080908a8>] dump_backtrace+0x0/0x380 > [<ffffff9008090c3c>] show_stack+0x14/0x20 > [<ffffff90087457b8>] dump_stack+0xe0/0x120 > [<ffffff90087b1360>] ubsan_epilogue+0x18/0x68 > [<ffffff90087b1a94>] __ubsan_handle_shift_out_of_bounds+0x18c/0x1bc > [<ffffff9008d89cb8>] dw_mci_setup_bus+0x3a0/0x438 > [...] > > UBSAN: Undefined behaviour in drivers/mmc/host/dw_mmc.c:1132:27 > shift exponent 250 is too large for 32-bit type 'unsigned int' > Call trace: > [<ffffff90080908a8>] dump_backtrace+0x0/0x380 > [<ffffff9008090c3c>] show_stack+0x14/0x20 > [<ffffff90087457b8>] dump_stack+0xe0/0x120 > [<ffffff90087b1360>] ubsan_epilogue+0x18/0x68 > [<ffffff90087b1a94>] __ubsan_handle_shift_out_of_bounds+0x18c/0x1bc > [<ffffff9008d89c9c>] dw_mci_setup_bus+0x384/0x438 The below message can be discarded. > [<ffffff9008d89ed4>] dw_mci_set_ios+0x184/0x798 > [<ffffff9008d550ac>] mmc_power_up+0x11c/0x260 > [<ffffff9008d56b78>] mmc_start_host+0x88/0x100 > [<ffffff9008d583f4>] mmc_add_host+0x6c/0x128 > [<ffffff9008d88f90>] dw_mci_probe+0x1088/0x1750 > [<ffffff9008d8caa8>] dw_mci_pltfm_register+0x108/0x178 > [<ffffff9008d8dae4>] dw_mci_exynos_probe+0x4c/0x88 > [<ffffff9008a03838>] platform_drv_probe+0x78/0x180 > [<ffffff90089fe9fc>] driver_probe_device+0x144/0x460 > [<ffffff90089fee0c>] __driver_attach+0xf4/0x140 > [<ffffff90089fad98>] bus_for_each_dev+0xf0/0x160 > [<ffffff90089fdc9c>] driver_attach+0x34/0x58 > [<ffffff90089fd3e0>] bus_add_driver+0x2c0/0x398 > [<ffffff9008a00924>] driver_register+0xbc/0x1e0 > [<ffffff9008a02a94>] __platform_driver_register+0x84/0xa8 > [<ffffff9009dd5730>] dw_mci_exynos_pltfm_driver_init+0x18/0x20 > [<ffffff9008082df8>] do_one_initcall+0xa0/0x2c8 > [<ffffff9009d81780>] kernel_init_freeable+0x52c/0x5dc > [<ffffff9009519844>] kernel_init+0x1c/0xf8 > [<ffffff9008086e10>] ret_from_fork+0x10/0x40 > > Signed-off-by: Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx> > --- > drivers/mmc/host/dw_mmc.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 2cc6123..dff045e 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -1099,7 +1099,8 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) > > div = (host->bus_hz != clock) ? DIV_ROUND_UP(div, 2) : 0; > > - if ((clock << div) != slot->__clk_old || force_clkinit) > + if (((div < 32) ? (clock << div) : 0) != slot->__clk_old || Well, we don't expect that clock is 0. if clock is 0, it should be passed to " if (!clock)".. During initializing card, clock is 400KHz or less..I understood what you want to fix. But I taught this is not correct. > + force_clkinit) > dev_info(&slot->mmc->class_dev, > "Bus speed (slot %d) = %dHz (slot req %dHz, actual %dHZ div = %d)\n", > slot->id, host->bus_hz, clock, > @@ -1129,7 +1130,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) > mci_send_cmd(slot, sdmmc_cmd_bits, 0); > > /* keep the clock with reflecting clock dividor */ > - slot->__clk_old = clock << div; > + slot->__clk_old = (div < 32) ? (clock << div) : 0; Also, clock is not 0.. Best Regards, Jaehoon Chung > } > > host->current_speed = clock; > -- 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
