During the uvcg_video_pump() process, if an error occurs and
uvcg_queue_cancel() is called, the buffer queue will be cleared out, but
the current marker (queue->buf_used) of the active buffer (no longer
active) is not reset. On the next iteration of uvcg_video_pump() the
stale buf_used count will be used and the logic of min((unsigned
int)len, buf->bytesused - queue->buf_used) may incorrectly calculate a
nbytes size, causing an invalid memory access.
[80802.185460][ T315] configfs-gadget gadget: uvc: VS request completed
with status -18.
[80802.185519][ T315] configfs-gadget gadget: uvc: VS request completed
with status -18.
...
uvcg_queue_cancel() is called and the queue is cleared out, but the
marker queue->buf_used is not reset.
...
[80802.262328][ T8682] Unable to handle kernel paging request at virtual
address ffffffc03af9f000
...
...
[80802.263138][ T8682] Call trace:
[80802.263146][ T8682] __memcpy+0x12c/0x180
[80802.263155][ T8682] uvcg_video_pump+0xcc/0x1e0
[80802.263165][ T8682] process_one_work+0x2cc/0x568
[80802.263173][ T8682] worker_thread+0x28c/0x518
[80802.263181][ T8682] kthread+0x160/0x170
[80802.263188][ T8682] ret_from_fork+0x10/0x18
[80802.263198][ T8682] Code: a8c12829 a88130cb a8c130
Fixes: d692522577c0 ("usb: gadget/uvc: Port UVC webcam gadget to use videobuf2 framework")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Dan Vacura <w36195(a)motorola.com>
---
Changes in v3:
- Cc stable
Changes in v2:
- Add Fixes tag
drivers/usb/gadget/function/uvc_queue.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c
index d852ac9e47e7..2cda982f3765 100644
--- a/drivers/usb/gadget/function/uvc_queue.c
+++ b/drivers/usb/gadget/function/uvc_queue.c
@@ -264,6 +264,8 @@ void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect)
buf->state = UVC_BUF_STATE_ERROR;
vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_ERROR);
}
+ queue->buf_used = 0;
+
/* This must be protected by the irqlock spinlock to avoid race
* conditions between uvc_queue_buffer and the disconnection event that
* could result in an interruptible wait in uvc_dequeue_buffer. Do not
--
2.32.0
From: Mike Rapoport <rppt(a)linux.ibm.com>
The semantics of pfn_valid() is to check presence of the memory map for a
PFN and not whether a PFN is covered by the linear map. The memory map may
be present for NOMAP memory regions, but they won't be mapped in the linear
mapping. Accessing such regions via __va() when they are memremap()'ed
will cause a crash.
On v5.4.y the crash happens on qemu-arm with UEFI [1]:
<1>[ 0.084476] 8<--- cut here ---
<1>[ 0.084595] Unable to handle kernel paging request at virtual address dfb76000
<1>[ 0.084938] pgd = (ptrval)
<1>[ 0.085038] [dfb76000] *pgd=5f7fe801, *pte=00000000, *ppte=00000000
...
<4>[ 0.093923] [<c0ed6ce8>] (memcpy) from [<c16a06f8>] (dmi_setup+0x60/0x418)
<4>[ 0.094204] [<c16a06f8>] (dmi_setup) from [<c16a38d4>] (arm_dmi_init+0x8/0x10)
<4>[ 0.094408] [<c16a38d4>] (arm_dmi_init) from [<c0302e9c>] (do_one_initcall+0x50/0x228)
<4>[ 0.094619] [<c0302e9c>] (do_one_initcall) from [<c16011e4>] (kernel_init_freeable+0x15c/0x1f8)
<4>[ 0.094841] [<c16011e4>] (kernel_init_freeable) from [<c0f028cc>] (kernel_init+0x8/0x10c)
<4>[ 0.095057] [<c0f028cc>] (kernel_init) from [<c03010e8>] (ret_from_fork+0x14/0x2c)
On kernels v5.10.y and newer the same crash won't reproduce on ARM because
commit b10d6bca8720 ("arch, drivers: replace for_each_membock() with
for_each_mem_range()") changed the way memory regions are registered in the
resource tree, but that merely covers up the problem.
On ARM64 memory resources registered in yet another way and there the
issue of wrong usage of pfn_valid() to ensure availability of the linear
map is also covered.
Implement arch_memremap_can_ram_remap() on ARM and ARM64 to prevent access
to NOMAP regions via the linear mapping in memremap().
Link: https://lore.kernel.org/all/Yl65zxGgFzF1Okac@sirena.org.uk
Reported-by: "kernelci.org bot" <bot(a)kernelci.org>
Tested-by: Mark Brown <broonie(a)kernel.org>
Cc: stable(a)vger.kernel.org # 5.4+
Signed-off-by: Mike Rapoport <rppt(a)linux.ibm.com>
---
v2: don't remove pfn_valid() from try_ram_remap(), per Ard
arch/arm/include/asm/io.h | 3 +++
arch/arm/mm/ioremap.c | 8 ++++++++
arch/arm64/include/asm/io.h | 4 ++++
arch/arm64/mm/ioremap.c | 8 ++++++++
4 files changed, 23 insertions(+)
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index 0c70eb688a00..2a0739a2350b 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -440,6 +440,9 @@ extern void pci_iounmap(struct pci_dev *dev, void __iomem *addr);
#define ARCH_HAS_VALID_PHYS_ADDR_RANGE
extern int valid_phys_addr_range(phys_addr_t addr, size_t size);
extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size);
+extern bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
+ unsigned long flags);
+#define arch_memremap_can_ram_remap arch_memremap_can_ram_remap
#endif
/*
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index aa08bcb72db9..290702328a33 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -493,3 +493,11 @@ void __init early_ioremap_init(void)
{
early_ioremap_setup();
}
+
+bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
+ unsigned long flags)
+{
+ unsigned long pfn = PHYS_PFN(offset);
+
+ return memblock_is_map_memory(pfn);
+}
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 7fd836bea7eb..3995652daf81 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -192,4 +192,8 @@ extern void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size);
extern int valid_phys_addr_range(phys_addr_t addr, size_t size);
extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size);
+extern bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
+ unsigned long flags);
+#define arch_memremap_can_ram_remap arch_memremap_can_ram_remap
+
#endif /* __ASM_IO_H */
diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
index b7c81dacabf0..b21f91cd830d 100644
--- a/arch/arm64/mm/ioremap.c
+++ b/arch/arm64/mm/ioremap.c
@@ -99,3 +99,11 @@ void __init early_ioremap_init(void)
{
early_ioremap_setup();
}
+
+bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
+ unsigned long flags)
+{
+ unsigned long pfn = PHYS_PFN(offset);
+
+ return pfn_is_map_memory(pfn);
+}
base-commit: b2d229d4ddb17db541098b83524d901257e93845
--
2.28.0
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