The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From bd6742249b9ca918565e4e3abaa06665e587f4b5 Mon Sep 17 00:00:00 2001
From: Jack Pham <jackp(a)codeaurora.org>
Date: Thu, 10 Jan 2019 12:39:55 -0800
Subject: [PATCH] usb: dwc3: gadget: Clear req->needs_extra_trb flag on cleanup
OUT endpoint requests may somtimes have this flag set when
preparing to be submitted to HW indicating that there is an
additional TRB chained to the request for alignment purposes.
If that request is removed before the controller can execute the
transfer (e.g. ep_dequeue/ep_disable), the request will not go
through the dwc3_gadget_ep_cleanup_completed_request() handler
and will not have its needs_extra_trb flag cleared when
dwc3_gadget_giveback() is called. This same request could be
later requeued for a new transfer that does not require an
extra TRB and if it is successfully completed, the cleanup
and TRB reclamation will incorrectly process the additional TRB
which belongs to the next request, and incorrectly advances the
TRB dequeue pointer, thereby messing up calculation of the next
requeust's actual/remaining count when it completes.
The right thing to do here is to ensure that the flag is cleared
before it is given back to the function driver. A good place
to do that is in dwc3_gadget_del_and_unmap_request().
Fixes: c6267a51639b ("usb: dwc3: gadget: align transfers to wMaxPacketSize")
Cc: stable(a)vger.kernel.org
Signed-off-by: Jack Pham <jackp(a)codeaurora.org>
Signed-off-by: Felipe Balbi <felipe.balbi(a)linux.intel.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 851fd44d56ad..6e2b6d6369aa 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -177,6 +177,7 @@ static void dwc3_gadget_del_and_unmap_request(struct dwc3_ep *dep,
req->started = false;
list_del(&req->list);
req->remaining = 0;
+ req->needs_extra_trb = false;
if (req->request.status == -EINPROGRESS)
req->request.status = status;
The patch below does not apply to the 4.20-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From bd6742249b9ca918565e4e3abaa06665e587f4b5 Mon Sep 17 00:00:00 2001
From: Jack Pham <jackp(a)codeaurora.org>
Date: Thu, 10 Jan 2019 12:39:55 -0800
Subject: [PATCH] usb: dwc3: gadget: Clear req->needs_extra_trb flag on cleanup
OUT endpoint requests may somtimes have this flag set when
preparing to be submitted to HW indicating that there is an
additional TRB chained to the request for alignment purposes.
If that request is removed before the controller can execute the
transfer (e.g. ep_dequeue/ep_disable), the request will not go
through the dwc3_gadget_ep_cleanup_completed_request() handler
and will not have its needs_extra_trb flag cleared when
dwc3_gadget_giveback() is called. This same request could be
later requeued for a new transfer that does not require an
extra TRB and if it is successfully completed, the cleanup
and TRB reclamation will incorrectly process the additional TRB
which belongs to the next request, and incorrectly advances the
TRB dequeue pointer, thereby messing up calculation of the next
requeust's actual/remaining count when it completes.
The right thing to do here is to ensure that the flag is cleared
before it is given back to the function driver. A good place
to do that is in dwc3_gadget_del_and_unmap_request().
Fixes: c6267a51639b ("usb: dwc3: gadget: align transfers to wMaxPacketSize")
Cc: stable(a)vger.kernel.org
Signed-off-by: Jack Pham <jackp(a)codeaurora.org>
Signed-off-by: Felipe Balbi <felipe.balbi(a)linux.intel.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 851fd44d56ad..6e2b6d6369aa 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -177,6 +177,7 @@ static void dwc3_gadget_del_and_unmap_request(struct dwc3_ep *dep,
req->started = false;
list_del(&req->list);
req->remaining = 0;
+ req->needs_extra_trb = false;
if (req->request.status == -EINPROGRESS)
req->request.status = status;
The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From bb364890323cca6e43f13e86d190ebf34a7d8cea Mon Sep 17 00:00:00 2001
From: Remi Pommarel <repk(a)triplefau.lt>
Date: Fri, 11 Jan 2019 00:01:35 +0100
Subject: [PATCH] mmc: meson-gx: Free irq in release() callback
Because the irq was requested through device managed resources API
(devm_request_threaded_irq()) it was freed after meson_mmc_remove()
completion, thus after mmc_free_host() has reclaimed meson_host memory.
As this irq is IRQF_SHARED, while using CONFIG_DEBUG_SHIRQ, its handler
get called by free_irq(). So meson_mmc_irq() was called after the
meson_host memory reclamation and was using invalid memory.
We ended up with the following scenario:
device_release_driver()
meson_mmc_remove()
mmc_free_host() /* Freeing host memory */
...
devres_release_all()
devm_irq_release()
__free_irq()
meson_mmc_irq() /* Uses freed memory */
To avoid this, the irq is released in meson_mmc_remove() and in
mseon_mmc_probe() error path before mmc_free_host() gets called.
Reported-by: Elie Roudninski <xademax(a)gmail.com>
Signed-off-by: Remi Pommarel <repk(a)triplefau.lt>
Cc: stable(a)vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson(a)linaro.org>
diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index c2690c1a50ff..f115d7c63ffe 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -179,6 +179,8 @@ struct meson_host {
struct sd_emmc_desc *descs;
dma_addr_t descs_dma_addr;
+ int irq;
+
bool vqmmc_enabled;
};
@@ -1231,7 +1233,7 @@ static int meson_mmc_probe(struct platform_device *pdev)
struct resource *res;
struct meson_host *host;
struct mmc_host *mmc;
- int ret, irq;
+ int ret;
mmc = mmc_alloc_host(sizeof(struct meson_host), &pdev->dev);
if (!mmc)
@@ -1276,8 +1278,8 @@ static int meson_mmc_probe(struct platform_device *pdev)
goto free_host;
}
- irq = platform_get_irq(pdev, 0);
- if (irq <= 0) {
+ host->irq = platform_get_irq(pdev, 0);
+ if (host->irq <= 0) {
dev_err(&pdev->dev, "failed to get interrupt resource.\n");
ret = -EINVAL;
goto free_host;
@@ -1331,9 +1333,8 @@ static int meson_mmc_probe(struct platform_device *pdev)
writel(IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN,
host->regs + SD_EMMC_IRQ_EN);
- ret = devm_request_threaded_irq(&pdev->dev, irq, meson_mmc_irq,
- meson_mmc_irq_thread, IRQF_SHARED,
- NULL, host);
+ ret = request_threaded_irq(host->irq, meson_mmc_irq,
+ meson_mmc_irq_thread, IRQF_SHARED, NULL, host);
if (ret)
goto err_init_clk;
@@ -1351,7 +1352,7 @@ static int meson_mmc_probe(struct platform_device *pdev)
if (host->bounce_buf == NULL) {
dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n");
ret = -ENOMEM;
- goto err_init_clk;
+ goto err_free_irq;
}
host->descs = dma_alloc_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
@@ -1370,6 +1371,8 @@ static int meson_mmc_probe(struct platform_device *pdev)
err_bounce_buf:
dma_free_coherent(host->dev, host->bounce_buf_size,
host->bounce_buf, host->bounce_dma_addr);
+err_free_irq:
+ free_irq(host->irq, host);
err_init_clk:
clk_disable_unprepare(host->mmc_clk);
err_core_clk:
@@ -1387,6 +1390,7 @@ static int meson_mmc_remove(struct platform_device *pdev)
/* disable interrupts */
writel(0, host->regs + SD_EMMC_IRQ_EN);
+ free_irq(host->irq, host);
dma_free_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
host->descs, host->descs_dma_addr);
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From bb364890323cca6e43f13e86d190ebf34a7d8cea Mon Sep 17 00:00:00 2001
From: Remi Pommarel <repk(a)triplefau.lt>
Date: Fri, 11 Jan 2019 00:01:35 +0100
Subject: [PATCH] mmc: meson-gx: Free irq in release() callback
Because the irq was requested through device managed resources API
(devm_request_threaded_irq()) it was freed after meson_mmc_remove()
completion, thus after mmc_free_host() has reclaimed meson_host memory.
As this irq is IRQF_SHARED, while using CONFIG_DEBUG_SHIRQ, its handler
get called by free_irq(). So meson_mmc_irq() was called after the
meson_host memory reclamation and was using invalid memory.
We ended up with the following scenario:
device_release_driver()
meson_mmc_remove()
mmc_free_host() /* Freeing host memory */
...
devres_release_all()
devm_irq_release()
__free_irq()
meson_mmc_irq() /* Uses freed memory */
To avoid this, the irq is released in meson_mmc_remove() and in
mseon_mmc_probe() error path before mmc_free_host() gets called.
Reported-by: Elie Roudninski <xademax(a)gmail.com>
Signed-off-by: Remi Pommarel <repk(a)triplefau.lt>
Cc: stable(a)vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson(a)linaro.org>
diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index c2690c1a50ff..f115d7c63ffe 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -179,6 +179,8 @@ struct meson_host {
struct sd_emmc_desc *descs;
dma_addr_t descs_dma_addr;
+ int irq;
+
bool vqmmc_enabled;
};
@@ -1231,7 +1233,7 @@ static int meson_mmc_probe(struct platform_device *pdev)
struct resource *res;
struct meson_host *host;
struct mmc_host *mmc;
- int ret, irq;
+ int ret;
mmc = mmc_alloc_host(sizeof(struct meson_host), &pdev->dev);
if (!mmc)
@@ -1276,8 +1278,8 @@ static int meson_mmc_probe(struct platform_device *pdev)
goto free_host;
}
- irq = platform_get_irq(pdev, 0);
- if (irq <= 0) {
+ host->irq = platform_get_irq(pdev, 0);
+ if (host->irq <= 0) {
dev_err(&pdev->dev, "failed to get interrupt resource.\n");
ret = -EINVAL;
goto free_host;
@@ -1331,9 +1333,8 @@ static int meson_mmc_probe(struct platform_device *pdev)
writel(IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN,
host->regs + SD_EMMC_IRQ_EN);
- ret = devm_request_threaded_irq(&pdev->dev, irq, meson_mmc_irq,
- meson_mmc_irq_thread, IRQF_SHARED,
- NULL, host);
+ ret = request_threaded_irq(host->irq, meson_mmc_irq,
+ meson_mmc_irq_thread, IRQF_SHARED, NULL, host);
if (ret)
goto err_init_clk;
@@ -1351,7 +1352,7 @@ static int meson_mmc_probe(struct platform_device *pdev)
if (host->bounce_buf == NULL) {
dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n");
ret = -ENOMEM;
- goto err_init_clk;
+ goto err_free_irq;
}
host->descs = dma_alloc_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
@@ -1370,6 +1371,8 @@ static int meson_mmc_probe(struct platform_device *pdev)
err_bounce_buf:
dma_free_coherent(host->dev, host->bounce_buf_size,
host->bounce_buf, host->bounce_dma_addr);
+err_free_irq:
+ free_irq(host->irq, host);
err_init_clk:
clk_disable_unprepare(host->mmc_clk);
err_core_clk:
@@ -1387,6 +1390,7 @@ static int meson_mmc_remove(struct platform_device *pdev)
/* disable interrupts */
writel(0, host->regs + SD_EMMC_IRQ_EN);
+ free_irq(host->irq, host);
dma_free_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
host->descs, host->descs_dma_addr);
The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 2bd44dadd5bfb4135162322fd0b45a174d4ad5bf Mon Sep 17 00:00:00 2001
From: Stefan Wahren <stefan.wahren(a)i2se.com>
Date: Sun, 23 Dec 2018 21:59:17 +0100
Subject: [PATCH] mmc: sdhci-iproc: handle mmc_of_parse() errors during probe
We need to handle mmc_of_parse() errors during probe.
This finally fixes the wifi regression on Raspberry Pi 3 series.
In error case the wifi chip was permanently in reset because of
the power sequence depending on the deferred probe of the GPIO expander.
Fixes: b580c52d58d9 ("mmc: sdhci-iproc: add IPROC SDHCI driver")
Cc: stable(a)vger.kernel.org
Signed-off-by: Stefan Wahren <stefan.wahren(a)i2se.com>
Acked-by: Adrian Hunter <adrian.hunter(a)intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson(a)linaro.org>
diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
index 0db99057c44f..9d12c06c7fd6 100644
--- a/drivers/mmc/host/sdhci-iproc.c
+++ b/drivers/mmc/host/sdhci-iproc.c
@@ -296,7 +296,10 @@ static int sdhci_iproc_probe(struct platform_device *pdev)
iproc_host->data = iproc_data;
- mmc_of_parse(host->mmc);
+ ret = mmc_of_parse(host->mmc);
+ if (ret)
+ goto err;
+
sdhci_get_property(pdev);
host->mmc->caps |= iproc_host->data->mmc_caps;
The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 2bd44dadd5bfb4135162322fd0b45a174d4ad5bf Mon Sep 17 00:00:00 2001
From: Stefan Wahren <stefan.wahren(a)i2se.com>
Date: Sun, 23 Dec 2018 21:59:17 +0100
Subject: [PATCH] mmc: sdhci-iproc: handle mmc_of_parse() errors during probe
We need to handle mmc_of_parse() errors during probe.
This finally fixes the wifi regression on Raspberry Pi 3 series.
In error case the wifi chip was permanently in reset because of
the power sequence depending on the deferred probe of the GPIO expander.
Fixes: b580c52d58d9 ("mmc: sdhci-iproc: add IPROC SDHCI driver")
Cc: stable(a)vger.kernel.org
Signed-off-by: Stefan Wahren <stefan.wahren(a)i2se.com>
Acked-by: Adrian Hunter <adrian.hunter(a)intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson(a)linaro.org>
diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
index 0db99057c44f..9d12c06c7fd6 100644
--- a/drivers/mmc/host/sdhci-iproc.c
+++ b/drivers/mmc/host/sdhci-iproc.c
@@ -296,7 +296,10 @@ static int sdhci_iproc_probe(struct platform_device *pdev)
iproc_host->data = iproc_data;
- mmc_of_parse(host->mmc);
+ ret = mmc_of_parse(host->mmc);
+ if (ret)
+ goto err;
+
sdhci_get_property(pdev);
host->mmc->caps |= iproc_host->data->mmc_caps;
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 2bd44dadd5bfb4135162322fd0b45a174d4ad5bf Mon Sep 17 00:00:00 2001
From: Stefan Wahren <stefan.wahren(a)i2se.com>
Date: Sun, 23 Dec 2018 21:59:17 +0100
Subject: [PATCH] mmc: sdhci-iproc: handle mmc_of_parse() errors during probe
We need to handle mmc_of_parse() errors during probe.
This finally fixes the wifi regression on Raspberry Pi 3 series.
In error case the wifi chip was permanently in reset because of
the power sequence depending on the deferred probe of the GPIO expander.
Fixes: b580c52d58d9 ("mmc: sdhci-iproc: add IPROC SDHCI driver")
Cc: stable(a)vger.kernel.org
Signed-off-by: Stefan Wahren <stefan.wahren(a)i2se.com>
Acked-by: Adrian Hunter <adrian.hunter(a)intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson(a)linaro.org>
diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
index 0db99057c44f..9d12c06c7fd6 100644
--- a/drivers/mmc/host/sdhci-iproc.c
+++ b/drivers/mmc/host/sdhci-iproc.c
@@ -296,7 +296,10 @@ static int sdhci_iproc_probe(struct platform_device *pdev)
iproc_host->data = iproc_data;
- mmc_of_parse(host->mmc);
+ ret = mmc_of_parse(host->mmc);
+ if (ret)
+ goto err;
+
sdhci_get_property(pdev);
host->mmc->caps |= iproc_host->data->mmc_caps;
The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 2bd44dadd5bfb4135162322fd0b45a174d4ad5bf Mon Sep 17 00:00:00 2001
From: Stefan Wahren <stefan.wahren(a)i2se.com>
Date: Sun, 23 Dec 2018 21:59:17 +0100
Subject: [PATCH] mmc: sdhci-iproc: handle mmc_of_parse() errors during probe
We need to handle mmc_of_parse() errors during probe.
This finally fixes the wifi regression on Raspberry Pi 3 series.
In error case the wifi chip was permanently in reset because of
the power sequence depending on the deferred probe of the GPIO expander.
Fixes: b580c52d58d9 ("mmc: sdhci-iproc: add IPROC SDHCI driver")
Cc: stable(a)vger.kernel.org
Signed-off-by: Stefan Wahren <stefan.wahren(a)i2se.com>
Acked-by: Adrian Hunter <adrian.hunter(a)intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson(a)linaro.org>
diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
index 0db99057c44f..9d12c06c7fd6 100644
--- a/drivers/mmc/host/sdhci-iproc.c
+++ b/drivers/mmc/host/sdhci-iproc.c
@@ -296,7 +296,10 @@ static int sdhci_iproc_probe(struct platform_device *pdev)
iproc_host->data = iproc_data;
- mmc_of_parse(host->mmc);
+ ret = mmc_of_parse(host->mmc);
+ if (ret)
+ goto err;
+
sdhci_get_property(pdev);
host->mmc->caps |= iproc_host->data->mmc_caps;
The patch below does not apply to the 3.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From a38662084c8bdb829ff486468c7ea801c13fcc34 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky(a)de.ibm.com>
Date: Tue, 8 Jan 2019 12:44:57 +0100
Subject: [PATCH] s390/mm: always force a load of the primary ASCE on context
switch
The ASCE of an mm_struct can be modified after a task has been created,
e.g. via crst_table_downgrade for a compat process. The active_mm logic
to avoid the switch_mm call if the next task is a kernel thread can
lead to a situation where switch_mm is called where 'prev == next' is
true but 'prev->context.asce == next->context.asce' is not.
This can lead to a situation where a CPU uses the outdated ASCE to run
a task. The result can be a crash, endless loops and really subtle
problem due to TLBs being created with an invalid ASCE.
Cc: stable(a)kernel.org # v3.15+
Fixes: 53e857f30867 ("s390/mm,tlb: race of lazy TLB flush vs. recreation")
Reported-by: Heiko Carstens <heiko.carstens(a)de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens(a)de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky(a)de.ibm.com>
diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index ccbb53e22024..e4462202200d 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -90,8 +90,6 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
{
int cpu = smp_processor_id();
- if (prev == next)
- return;
S390_lowcore.user_asce = next->context.asce;
cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
/* Clear previous user-ASCE from CR1 and CR7 */
@@ -103,7 +101,8 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
__ctl_load(S390_lowcore.vdso_asce, 7, 7);
clear_cpu_flag(CIF_ASCE_SECONDARY);
}
- cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
+ if (prev != next)
+ cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
}
#define finish_arch_post_lock_switch finish_arch_post_lock_switch
The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From a38662084c8bdb829ff486468c7ea801c13fcc34 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky(a)de.ibm.com>
Date: Tue, 8 Jan 2019 12:44:57 +0100
Subject: [PATCH] s390/mm: always force a load of the primary ASCE on context
switch
The ASCE of an mm_struct can be modified after a task has been created,
e.g. via crst_table_downgrade for a compat process. The active_mm logic
to avoid the switch_mm call if the next task is a kernel thread can
lead to a situation where switch_mm is called where 'prev == next' is
true but 'prev->context.asce == next->context.asce' is not.
This can lead to a situation where a CPU uses the outdated ASCE to run
a task. The result can be a crash, endless loops and really subtle
problem due to TLBs being created with an invalid ASCE.
Cc: stable(a)kernel.org # v3.15+
Fixes: 53e857f30867 ("s390/mm,tlb: race of lazy TLB flush vs. recreation")
Reported-by: Heiko Carstens <heiko.carstens(a)de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens(a)de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky(a)de.ibm.com>
diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index ccbb53e22024..e4462202200d 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -90,8 +90,6 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
{
int cpu = smp_processor_id();
- if (prev == next)
- return;
S390_lowcore.user_asce = next->context.asce;
cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
/* Clear previous user-ASCE from CR1 and CR7 */
@@ -103,7 +101,8 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
__ctl_load(S390_lowcore.vdso_asce, 7, 7);
clear_cpu_flag(CIF_ASCE_SECONDARY);
}
- cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
+ if (prev != next)
+ cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
}
#define finish_arch_post_lock_switch finish_arch_post_lock_switch