This patch removes following UBSAN warnings in dw_mci_setup_bus(). 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 warnings are caused because of shift with more than 31 on 32 bit variable, so this patch fixes to keep both clock and divider instead of shift. Signed-off-by: Seung-Woo Kim <[email protected]> --- drivers/mmc/host/dw_mmc.c | 8 +++++--- drivers/mmc/host/dw_mmc.h | 8 +++++--- 2 files changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 2cc6123..d05c8cc 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 (clock != slot->__clk_old || div != slot->__div_old || + 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, @@ -1128,8 +1129,9 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) /* inform CIU */ mci_send_cmd(slot, sdmmc_cmd_bits, 0); - /* keep the clock with reflecting clock dividor */ - slot->__clk_old = clock << div; + /* keep the clock and clock divider */ + slot->__clk_old = clock; + slot->__div_old = div; } host->current_speed = clock; diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h index 1e8d838..fdfc3f5 100644 --- a/drivers/mmc/host/dw_mmc.h +++ b/drivers/mmc/host/dw_mmc.h @@ -245,9 +245,10 @@ extern int dw_mci_resume(struct dw_mci *host); * @queue_node: List node for placing this node in the @queue list of * &struct dw_mci. * @clock: Clock rate configured by set_ios(). Protected by host->lock. - * @__clk_old: The last updated clock with reflecting clock divider. - * Keeping track of this helps us to avoid spamming the console - * with CONFIG_MMC_CLKGATE. + * @__clk_old: The last updated clock. + * @__div_old: The last updated clock divider. + * Keeping track of clock and clock divider helps us to avoid spamming + * the console with CONFIG_MMC_CLKGATE. * @flags: Random state bits associated with the slot. * @id: Number of this slot. * @sdio_id: Number of this slot in the SDIO interrupt registers. @@ -263,6 +264,7 @@ struct dw_mci_slot { unsigned int clock; unsigned int __clk_old; + unsigned int __div_old; unsigned long flags; #define DW_MMC_CARD_PRESENT 0 -- 1.7.4.1
