linux-stable.git/kernel/dma, branch v4.19.321

dma: fix call order in dmam_free_coherent

2024-08-19T03:32:06+00:00

[ Upstream commit 28e8b7406d3a1f5329a03aa25a43aa28e087cb20 ]

dmam_free_coherent() frees a DMA allocation, which makes the
freed vaddr available for reuse, then calls devres_destroy()
to remove and free the data structure used to track the DMA
allocation. Between the two calls, it is possible for a
concurrent task to make an allocation with the same vaddr
and add it to the devres list.

If this happens, there will be two entries in the devres list
with the same vaddr and devres_destroy() can free the wrong
entry, triggering the WARN_ON() in dmam_match.

Fix by destroying the devres entry before freeing the DMA
allocation.

Tested:
  kokonut //net/encryption
    http://sponge2/b9145fe6-0f72-4325-ac2f-a84d81075b03

Fixes: 9ac7849e35f7 ("devres: device resource management")
Signed-off-by: Lance Richardson 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Sasha Levin

dma-mapping: clear dev->dma_mem to NULL after freeing it

2024-01-25T22:33:34+00:00

[ Upstream commit b07bc2347672cc8c7293c64499f1488278c5ca3d ]

Reproduced with below sequence:
dma_declare_coherent_memory()->dma_release_coherent_memory()
->dma_declare_coherent_memory()->"return -EBUSY" error

It will return -EBUSY from the dma_assign_coherent_memory()
in dma_declare_coherent_memory(), the reason is that dev->dma_mem
pointer has not been set to NULL after it's freed.

Fixes: cf65a0f6f6ff ("dma-mapping: move all DMA mapping code to kernel/dma")
Signed-off-by: Joakim Zhang 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Sasha Levin

treewide: Remove uninitialized_var() usage

2023-08-11T09:45:01+00:00

commit 3f649ab728cda8038259d8f14492fe400fbab911 upstream.

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky  # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe  # IB
Acked-by: Kalle Valo  # wireless drivers
Reviewed-by: Chao Yu  # erofs
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

swiotlb: skip swiotlb_bounce when orig_addr is zero

2022-07-02T14:27:40+00:00

After patch ddbd89deb7d3 ("swiotlb: fix info leak with DMA_FROM_DEVICE"),
swiotlb_bounce will be called in swiotlb_tbl_map_single unconditionally.
This requires that the physical address must be valid, which is not always
true on stable-4.19 or earlier version.
On stable-4.19, swiotlb_alloc_buffer will call swiotlb_tbl_map_single with
orig_addr equal to zero, which cause such a panic:

Unable to handle kernel paging request at virtual address ffffb77a40000000
...
pc : __memcpy+0x100/0x180
lr : swiotlb_bounce+0x74/0x88
...
Call trace:
 __memcpy+0x100/0x180
 swiotlb_tbl_map_single+0x2c8/0x338
 swiotlb_alloc+0xb4/0x198
 __dma_alloc+0x84/0x1d8
 ...

On stable-4.9 and stable-4.14, swiotlb_alloc_coherent wille call map_single
with orig_addr equal to zero, which can cause same panic.

Fix this by skipping swiotlb_bounce when orig_addr is zero.

Fixes: ddbd89deb7d3 ("swiotlb: fix info leak with DMA_FROM_DEVICE")
Signed-off-by: Liu Shixin 
Signed-off-by: Greg Kroah-Hartman

dma-debug: change allocation mode from GFP_NOWAIT to GFP_ATIOMIC

2022-06-14T14:59:16+00:00

[ Upstream commit 84bc4f1dbbbb5f8aa68706a96711dccb28b518e5 ]

We observed the error "cacheline tracking ENOMEM, dma-debug disabled"
during a light system load (copying some files). The reason for this error
is that the dma_active_cacheline radix tree uses GFP_NOWAIT allocation -
so it can't access the emergency memory reserves and it fails as soon as
anybody reaches the watermark.

This patch changes GFP_NOWAIT to GFP_ATOMIC, so that it can access the
emergency memory reserves.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Sasha Levin

Reinstate some of "swiotlb: rework "fix info leak with DMA_FROM_DEVICE""

2022-05-25T07:10:41+00:00

commit 901c7280ca0d5e2b4a8929fbe0bfb007ac2a6544 upstream.

Halil Pasic points out [1] that the full revert of that commit (revert
in bddac7c1e02b), and that a partial revert that only reverts the
problematic case, but still keeps some of the cleanups is probably
better.  

And that partial revert [2] had already been verified by Oleksandr
Natalenko to also fix the issue, I had just missed that in the long
discussion.

So let's reinstate the cleanups from commit aa6f8dcbab47 ("swiotlb:
rework "fix info leak with DMA_FROM_DEVICE""), and effectively only
revert the part that caused problems.

Link: https://lore.kernel.org/all/20220328013731.017ae3e3.pasic@linux.ibm.com/ [1]
Link: https://lore.kernel.org/all/20220324055732.GB12078@lst.de/ [2]
Link: https://lore.kernel.org/all/4386660.LvFx2qVVIh@natalenko.name/ [3]
Suggested-by: Halil Pasic 
Tested-by: Oleksandr Natalenko 
Cc: Christoph Hellwig" 
Signed-off-by: Linus Torvalds 
[OP: backport to 4.19: adjusted context]
Signed-off-by: Ovidiu Panait 
Signed-off-by: Greg Kroah-Hartman

swiotlb: fix info leak with DMA_FROM_DEVICE

2022-05-25T07:10:41+00:00

commit ddbd89deb7d32b1fbb879f48d68fda1a8ac58e8e upstream.

The problem I'm addressing was discovered by the LTP test covering
cve-2018-1000204.

A short description of what happens follows:
1) The test case issues a command code 00 (TEST UNIT READY) via the SG_IO
   interface with: dxfer_len == 524288, dxdfer_dir == SG_DXFER_FROM_DEV
   and a corresponding dxferp. The peculiar thing about this is that TUR
   is not reading from the device.
2) In sg_start_req() the invocation of blk_rq_map_user() effectively
   bounces the user-space buffer. As if the device was to transfer into
   it. Since commit a45b599ad808 ("scsi: sg: allocate with __GFP_ZERO in
   sg_build_indirect()") we make sure this first bounce buffer is
   allocated with GFP_ZERO.
3) For the rest of the story we keep ignoring that we have a TUR, so the
   device won't touch the buffer we prepare as if the we had a
   DMA_FROM_DEVICE type of situation. My setup uses a virtio-scsi device
   and the  buffer allocated by SG is mapped by the function
   virtqueue_add_split() which uses DMA_FROM_DEVICE for the "in" sgs (here
   scatter-gather and not scsi generics). This mapping involves bouncing
   via the swiotlb (we need swiotlb to do virtio in protected guest like
   s390 Secure Execution, or AMD SEV).
4) When the SCSI TUR is done, we first copy back the content of the second
   (that is swiotlb) bounce buffer (which most likely contains some
   previous IO data), to the first bounce buffer, which contains all
   zeros.  Then we copy back the content of the first bounce buffer to
   the user-space buffer.
5) The test case detects that the buffer, which it zero-initialized,
  ain't all zeros and fails.

One can argue that this is an swiotlb problem, because without swiotlb
we leak all zeros, and the swiotlb should be transparent in a sense that
it does not affect the outcome (if all other participants are well
behaved).

Copying the content of the original buffer into the swiotlb buffer is
the only way I can think of to make swiotlb transparent in such
scenarios. So let's do just that if in doubt, but allow the driver
to tell us that the whole mapped buffer is going to be overwritten,
in which case we can preserve the old behavior and avoid the performance
impact of the extra bounce.

Signed-off-by: Halil Pasic 
Signed-off-by: Christoph Hellwig 
[OP: backport to 4.19: adjusted context]
Signed-off-by: Ovidiu Panait 
Signed-off-by: Greg Kroah-Hartman

dma-debug: fix return value of __setup handlers

2022-04-15T12:14:51+00:00

[ Upstream commit 80e4390981618e290616dbd06ea190d4576f219d ]

When valid kernel command line parameters
  dma_debug=off dma_debug_entries=100
are used, they are reported as Unknown parameters and added to init's
environment strings, polluting it.

  Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc5
    dma_debug=off dma_debug_entries=100", will be passed to user space.

and

 Run /sbin/init as init process
   with arguments:
     /sbin/init
   with environment:
     HOME=/
     TERM=linux
     BOOT_IMAGE=/boot/bzImage-517rc5
     dma_debug=off
     dma_debug_entries=100

Return 1 from these __setup handlers to indicate that the command line
option has been handled.

Fixes: 59d3daafa1726 ("dma-debug: add kernel command line parameters")
Signed-off-by: Randy Dunlap 
Reported-by: Igor Zhbanov 
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Cc: Joerg Roedel 
Cc: Christoph Hellwig 
Cc: Marek Szyprowski 
Cc: iommu@lists.linux-foundation.org
Cc: Robin Murphy 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Sasha Levin

dma-debug: fix sg checks in debug_dma_map_sg()

2021-10-27T07:53:12+00:00

[ Upstream commit 293d92cbbd2418ca2ba43fed07f1b92e884d1c77 ]

The following warning occurred sporadically on s390:
DMA-API: nvme 0006:00:00.0: device driver maps memory from kernel text or rodata [addr=0000000048cc5e2f] [len=131072]
WARNING: CPU: 4 PID: 825 at kernel/dma/debug.c:1083 check_for_illegal_area+0xa8/0x138

It is a false-positive warning, due to broken logic in debug_dma_map_sg().
check_for_illegal_area() checks for overlay of sg elements with kernel text
or rodata. It is called with sg_dma_len(s) instead of s->length as
parameter. After the call to ->map_sg(), sg_dma_len() will contain the
length of possibly combined sg elements in the DMA address space, and not
the individual sg element length, which would be s->length.

The check will then use the physical start address of an sg element, and
add the DMA length for the overlap check, which could result in the false
warning, because the DMA length can be larger than the actual single sg
element length.

In addition, the call to check_for_illegal_area() happens in the iteration
over mapped_ents, which will not include all individual sg elements if
any of them were combined in ->map_sg().

Fix this by using s->length instead of sg_dma_len(s). Also put the call to
check_for_illegal_area() in a separate loop, iterating over all the
individual sg elements ("nents" instead of "mapped_ents").

While at it, as suggested by Robin Murphy, also move check_for_stack()
inside the new loop, as it is similarly concerned with validating the
individual sg elements.

Link: https://lore.kernel.org/lkml/20210705185252.4074653-1-gerald.schaefer@linux.ibm.com
Fixes: 884d05970bfb ("dma-debug: use sg_dma_len accessor")
Signed-off-by: Gerald Schaefer 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Sasha Levin

swiotlb: fix "x86: Don't panic if can not alloc buffer for swiotlb"

2020-11-18T18:18:51+00:00

commit e9696d259d0fb5d239e8c28ca41089838ea76d13 upstream.

kernel/dma/swiotlb.c:swiotlb_init gets called first and tries to
allocate a buffer for the swiotlb. It does so by calling

  memblock_alloc_low(PAGE_ALIGN(bytes), PAGE_SIZE);

If the allocation must fail, no_iotlb_memory is set.

Later during initialization swiotlb-xen comes in
(drivers/xen/swiotlb-xen.c:xen_swiotlb_init) and given that io_tlb_start
is != 0, it thinks the memory is ready to use when actually it is not.

When the swiotlb is actually needed, swiotlb_tbl_map_single gets called
and since no_iotlb_memory is set the kernel panics.

Instead, if swiotlb-xen.c:xen_swiotlb_init knew the swiotlb hadn't been
initialized, it would do the initialization itself, which might still
succeed.

Fix the panic by setting io_tlb_start to 0 on swiotlb initialization
failure, and also by setting no_iotlb_memory to false on swiotlb
initialization success.

Fixes: ac2cbab21f31 ("x86: Don't panic if can not alloc buffer for swiotlb")

Reported-by: Elliott Mitchell 
Tested-by: Elliott Mitchell 
Signed-off-by: Stefano Stabellini 
Reviewed-by: Christoph Hellwig 
Cc: stable@vger.kernel.org
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman