linux.git/kernel/dma/debug.c, branch v5.4.219

dma-debug: make things less spammy under memory pressure

2022-06-22T12:11:19+00:00

[ Upstream commit e19f8fa6ce1ca9b8b934ba7d2e8f34c95abc6e60 ]

Limit the error msg to avoid flooding the console.  If you have a lot of
threads hitting this at once, they could have already gotten passed the
dma_debug_disabled() check before they get to the point of allocation
failure, resulting in quite a lot of this error message spamming the
log.  Use pr_err_once() to limit that.

Signed-off-by: Rob Clark 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Sasha Levin

dma-debug: change allocation mode from GFP_NOWAIT to GFP_ATIOMIC

2022-06-14T16:11:28+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

dma-debug: fix return value of __setup handlers

2022-04-15T12:18:18+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()

2021-10-27T07:54:25+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

dma-debug: fix debugfs initialization order

2021-09-22T10:26:24+00:00

[ Upstream commit 173735c346c412d9f084825ecb04f24ada0e2986 ]

Due to link order, dma_debug_init is called before debugfs has a chance
to initialize (via debugfs_init which also happens in the core initcall
stage), so the directories for dma-debug are never created.

Decouple dma_debug_fs_init from dma_debug_init and defer its init until
core_initcall_sync (after debugfs has been initialized) while letting
dma-debug initialization occur as soon as possible to catch any early
mappings, as suggested in [1].

[1] https://lore.kernel.org/linux-iommu/YIgGa6yF%2Fadg8OSN@kroah.com/

Fixes: 15b28bbcd567 ("dma-debug: move initialization to common code")
Signed-off-by: Anthony Iliopoulos 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Sasha Levin

dma-debug: fix displaying of dma allocation type

2020-04-23T08:36:43+00:00

commit 9bb50ed7470944238ec8e30a94ef096caf9056ee upstream.

The commit 2e05ea5cdc1a ("dma-mapping: implement dma_map_single_attrs using
dma_map_page_attrs") removed "dma_debug_page" enum, but missed to update
type2name string table. This causes incorrect displaying of dma allocation
type.
Fix it by removing "page" string from type2name string table and switch to
use named initializers.

Before (dma_alloc_coherent()):
k3-ringacc 4b800000.ringacc: scather-gather idx 2208 P=d1140000 N=d114 D=d1140000 L=40 DMA_BIDIRECTIONAL dma map error check not applicable
k3-ringacc 4b800000.ringacc: scather-gather idx 2216 P=d1150000 N=d115 D=d1150000 L=40 DMA_BIDIRECTIONAL dma map error check not applicable

After:
k3-ringacc 4b800000.ringacc: coherent idx 2208 P=d1140000 N=d114 D=d1140000 L=40 DMA_BIDIRECTIONAL dma map error check not applicable
k3-ringacc 4b800000.ringacc: coherent idx 2216 P=d1150000 N=d115 D=d1150000 L=40 DMA_BIDIRECTIONAL dma map error check not applicable

Fixes: 2e05ea5cdc1a ("dma-mapping: implement dma_map_single_attrs using dma_map_page_attrs")
Signed-off-by: Grygorii Strashko 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Greg Kroah-Hartman

dma-debug: add a schedule point in debug_dma_dump_mappings()

2020-01-04T18:16:57+00:00

[ Upstream commit 9ff6aa027dbb98755f0265695354f2dd07c0d1ce ]

debug_dma_dump_mappings() can take a lot of cpu cycles :

lpk43:/# time wc -l /sys/kernel/debug/dma-api/dump
163435 /sys/kernel/debug/dma-api/dump

real	0m0.463s
user	0m0.003s
sys	0m0.459s

Let's add a cond_resched() to avoid holding cpu for too long.

Signed-off-by: Eric Dumazet 
Cc: Corentin Labbe 
Cc: Christoph Hellwig 
Cc: Marek Szyprowski 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Sasha Levin

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333

2019-06-05T15:37:06+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 59 temple place suite 330 boston ma 02111
  1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 136 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Alexios Zavras 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000436.384967451@linutronix.de
Signed-off-by: Greg Kroah-Hartman

dma/debug: Simplify stracktrace retrieval

2019-04-29T10:37:50+00:00

Replace the indirection through struct stack_trace with an invocation of
the storage array based interface.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Josh Poimboeuf 
Cc: Andy Lutomirski 
Cc: iommu@lists.linux-foundation.org
Cc: Robin Murphy 
Cc: Marek Szyprowski 
Cc: Steven Rostedt 
Cc: Alexander Potapenko 
Cc: Alexey Dobriyan 
Cc: Andrew Morton 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: linux-mm@kvack.org
Cc: David Rientjes 
Cc: Catalin Marinas 
Cc: Dmitry Vyukov 
Cc: Andrey Ryabinin 
Cc: kasan-dev@googlegroups.com
Cc: Mike Rapoport 
Cc: Akinobu Mita 
Cc: Johannes Thumshirn 
Cc: David Sterba 
Cc: Chris Mason 
Cc: Josef Bacik 
Cc: linux-btrfs@vger.kernel.org
Cc: dm-devel@redhat.com
Cc: Mike Snitzer 
Cc: Alasdair Kergon 
Cc: Daniel Vetter 
Cc: intel-gfx@lists.freedesktop.org
Cc: Joonas Lahtinen 
Cc: Maarten Lankhorst 
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie 
Cc: Jani Nikula 
Cc: Rodrigo Vivi 
Cc: Tom Zanussi 
Cc: Miroslav Benes 
Cc: linux-arch@vger.kernel.org
Link: https://lkml.kernel.org/r/20190425094802.248658135@linutronix.de

dma-debug: only skip one stackframe entry

2019-04-11T17:29:50+00:00

With skip set to 1, I get a traceback like this:

[  106.867637] DMA-API: Mapped at:
[  106.870784]  afu_dma_map_region+0x2cd/0x4f0 [dfl_afu]
[  106.875839]  afu_ioctl+0x258/0x380 [dfl_afu]
[  106.880108]  do_vfs_ioctl+0xa9/0x720
[  106.883688]  ksys_ioctl+0x60/0x90
[  106.887007]  __x64_sys_ioctl+0x16/0x20

With the previous value of 2, afu_dma_map_region was being omitted.  I
suspect that the code paths have simply changed since the value of 2 was
chosen a decade ago, but it's also possible that it varies based on which
mapping function was used, compiler inlining choices, etc.  In any case,
it's best to err on the side of skipping less.

Signed-off-by: Scott Wood 
Signed-off-by: Christoph Hellwig