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d4d1144908
As soon as the CD IRQ is requested, it can trigger, since it's an
externally controlled event. If it does, delayed_work host->detect will
be scheduled.
Many host controller probe()s are roughly structured as:
*_probe() {
host = sdhci_pltfm_init();
mmc_of_parse(host->mmc);
rc = sdhci_add_host(host);
if (rc) {
sdhci_pltfm_free();
return rc;
}
In 3.17, CD IRQs can are enabled quite early via *_probe() ->
mmc_of_parse() -> mmc_gpio_request_cd() -> mmc_gpiod_request_cd_irq().
Note that in linux-next, mmc_of_parse() calls mmc_gpio*d*_request_cd()
rather than mmc_gpio_request_cd(), and mmc_gpio*d*_request_cd() doesn't
call mmc_gpiod_request_cd_irq(). However, this issue still exists if
mmc_gpio_request_cd() is called directly before mmc_start_host().
sdhci_add_host() may fail part way through (e.g. due to deferred
probe for a vmmc regulator), and sdhci_pltfm_free() does nothing to
unrequest the CD IRQ nor cancel the delayed_work. sdhci_pltfm_free() is
coded to assume that if sdhci_add_host() failed, then the delayed_work
cannot (or should not) have been triggered.
This can lead to the following with CONFIG_DEBUG_OBJECTS_* enabled, when
kfree(host) is eventually called inside sdhci_pltfm_free():
WARNING: CPU: 2 PID: 6 at lib/debugobjects.c:263 debug_print_object+0x8c/0xb4()
ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x18
The object being complained about is host->detect.
There's no need to request the CD IRQ so early; mmc_start_host() already
requests it. For most SDHCI hosts at least, the typical call path that
does this is: *_probe() -> sdhci_add_host() -> mmc_add_host() ->
mmc_start_host(). Therefore, remove the call to mmc_gpiod_request_cd_irq()
from mmc_gpio_request_cd(). This also matches mmc_gpio*d*_request_cd(),
which already doesn't call mmc_gpiod_request_cd_irq().
However, some host controller drivers call mmc_gpio_request_cd() after
mmc_start_host() has already been called, and assume that this will also
call mmc_gpiod_request_cd_irq(). Update those drivers to explicitly call
mmc_gpiod_request_cd_irq() themselves. Ideally, these drivers should be
modified to move their call to mmc_gpio_request_cd() before their call
to mmc_add_host(). However that's too large a change for stable.
This solves the problem (eliminates the kernel error message above),
since it guarantees that the IRQ can't trigger before mmc_start_host()
is called.
The critical point here is that once sdhci_add_host() calls
mmc_add_host() -> mmc_start_host(), sdhci_add_host() is coded not to
fail. In other words, if there's a chance that mmc_start_host() may have
been called, and CD IRQs triggered, and the delayed_work scheduled,
sdhci_add_host() won't fail, and so cleanup is no longer via
sdhci_pltfm_free() (which doesn't free the IRQ or cancel the work queue)
but instead must be via sdhci_remove_host(), which calls mmc_remove_host()
-> mmc_stop_host(), which does free the IRQ and cancel the work queue.
CC: Russell King <linux@arm.linux.org.uk>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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|---|---|---|
| .. | ||
| android-goldfish.c | ||
| atmel-mci-regs.h | ||
| atmel-mci.c | ||
| au1xmmc.c | ||
| bfin_sdh.c | ||
| cb710-mmc.c | ||
| cb710-mmc.h | ||
| davinci_mmc.c | ||
| dw_mmc-exynos.c | ||
| dw_mmc-k3.c | ||
| dw_mmc-pci.c | ||
| dw_mmc-pltfm.c | ||
| dw_mmc-pltfm.h | ||
| dw_mmc-rockchip.c | ||
| dw_mmc.c | ||
| dw_mmc.h | ||
| jz4740_mmc.c | ||
| Kconfig | ||
| Makefile | ||
| mmc_spi.c | ||
| mmci_qcom_dml.c | ||
| mmci_qcom_dml.h | ||
| mmci.c | ||
| mmci.h | ||
| moxart-mmc.c | ||
| msm_sdcc.c | ||
| msm_sdcc.h | ||
| mvsdio.c | ||
| mvsdio.h | ||
| mxcmmc.c | ||
| mxs-mmc.c | ||
| of_mmc_spi.c | ||
| omap_hsmmc.c | ||
| omap.c | ||
| pxamci.c | ||
| pxamci.h | ||
| rtsx_pci_sdmmc.c | ||
| rtsx_usb_sdmmc.c | ||
| s3cmci.c | ||
| s3cmci.h | ||
| sdhci-acpi.c | ||
| sdhci-bcm2835.c | ||
| sdhci-bcm-kona.c | ||
| sdhci-cns3xxx.c | ||
| sdhci-dove.c | ||
| sdhci-esdhc-imx.c | ||
| sdhci-esdhc.h | ||
| sdhci-msm.c | ||
| sdhci-of-arasan.c | ||
| sdhci-of-esdhc.c | ||
| sdhci-of-hlwd.c | ||
| sdhci-pci-data.c | ||
| sdhci-pci-o2micro.c | ||
| sdhci-pci-o2micro.h | ||
| sdhci-pci.c | ||
| sdhci-pci.h | ||
| sdhci-pltfm.c | ||
| sdhci-pltfm.h | ||
| sdhci-pxav2.c | ||
| sdhci-pxav3.c | ||
| sdhci-s3c-regs.h | ||
| sdhci-s3c.c | ||
| sdhci-sirf.c | ||
| sdhci-spear.c | ||
| sdhci-st.c | ||
| sdhci-tegra.c | ||
| sdhci.c | ||
| sdhci.h | ||
| sdricoh_cs.c | ||
| sh_mmcif.c | ||
| sh_mobile_sdhi.c | ||
| sunxi-mmc.c | ||
| tifm_sd.c | ||
| tmio_mmc_dma.c | ||
| tmio_mmc_pio.c | ||
| tmio_mmc.c | ||
| tmio_mmc.h | ||
| usdhi6rol0.c | ||
| ushc.c | ||
| via-sdmmc.c | ||
| vub300.c | ||
| wbsd.c | ||
| wbsd.h | ||
| wmt-sdmmc.c | ||