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m1721: backport new zstd from linux mainline #7

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@urain39 urain39 commented Jul 12, 2022

This backport is only for zRAM/zSwap, all fs related changes have been removed.

masahir0y and others added 17 commits July 7, 2022 20:39
Now, Kbuild nicely handles composite objects to avoid multiple
definition.

Makefiles can simply add the same objects multiple times across
composite objects.

Signed-off-by: Masahiro Yamada <[email protected]>
In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warnings:

lib/zstd/bitstream.h:261:30: warning: this statement may fall through [-Wimplicit-fallthrough=]
lib/zstd/bitstream.h:262:30: warning: this statement may fall through [-Wimplicit-fallthrough=]
lib/zstd/bitstream.h:263:30: warning: this statement may fall through [-Wimplicit-fallthrough=]
lib/zstd/bitstream.h:264:30: warning: this statement may fall through [-Wimplicit-fallthrough=]
lib/zstd/bitstream.h:265:30: warning: this statement may fall through [-Wimplicit-fallthrough=]
lib/zstd/compress.c:3183:16: warning: this statement may fall through [-Wimplicit-fallthrough=]
lib/zstd/decompress.c:1770:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
lib/zstd/decompress.c:2376:15: warning: this statement may fall through [-Wimplicit-fallthrough=]
lib/zstd/decompress.c:2404:15: warning: this statement may fall through [-Wimplicit-fallthrough=]
lib/zstd/decompress.c:2435:16: warning: this statement may fall through [-Wimplicit-fallthrough=]
lib/zstd/huf_compress.c: In function ‘HUF_compress1X_usingCTable’:
lib/zstd/huf_compress.c:535:5: warning: this statement may fall through [-Wimplicit-fallthrough=]
  if (sizeof((stream)->bitContainer) * 8 < HUF_TABLELOG_MAX * 4 + 7) \
     ^
lib/zstd/huf_compress.c:558:54: note: in expansion of macro ‘HUF_FLUSHBITS_2’
  case 3: HUF_encodeSymbol(&bitC, ip[n + 2], CTable); HUF_FLUSHBITS_2(&bitC);
                                                      ^~~~~~~~~~~~~~~
lib/zstd/huf_compress.c:559:2: note: here
  case 2: HUF_encodeSymbol(&bitC, ip[n + 1], CTable); HUF_FLUSHBITS_1(&bitC);
  ^~~~
lib/zstd/huf_compress.c:531:5: warning: this statement may fall through [-Wimplicit-fallthrough=]
  if (sizeof((stream)->bitContainer) * 8 < HUF_TABLELOG_MAX * 2 + 7) \
     ^
lib/zstd/huf_compress.c:559:54: note: in expansion of macro ‘HUF_FLUSHBITS_1’
  case 2: HUF_encodeSymbol(&bitC, ip[n + 1], CTable); HUF_FLUSHBITS_1(&bitC);
                                                      ^~~~~~~~~~~~~~~
lib/zstd/huf_compress.c:560:2: note: here
  case 1: HUF_encodeSymbol(&bitC, ip[n + 0], CTable); HUF_FLUSHBITS(&bitC);
  ^~~~
  AR      lib/zstd//built-in.a

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enabling -Wimplicit-fallthrough.

Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Gustavo A. R. Silva <[email protected]>
Currently, compiler_types.h #defines __inline as inline (and further
#defines inline to automatically attach some attributes), so this does
not change functionality. It serves as preparation for removing the
#define of __inline.

While at it, also remove the __attribute__((unused)) - it's already
included in the definition of the inline macro, and "open-coded"
__attribute__(()) should be avoided.

Since commit a95b37e20db9 (kbuild: get <linux/compiler_types.h> out of
<linux/kconfig.h>), compiler_types.h is automatically included by all
kernel C code - i.e., the definition of inline including the unused
attribute is guaranteed to be in effect whenever ZSTD_STATIC is
expanded.

Signed-off-by: Rasmus Villemoes <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
These changes are necessary to get the build to work in the preboot
environment, and to get reasonable performance:

- Remove a double definition of the CHECK_F macro when the zstd
  library is amalgamated.

- Switch ZSTD_copy8() to __builtin_memcpy(), because in the preboot
  environment on x86 gcc can't inline `memcpy()` otherwise.

- Limit the gcc hack in ZSTD_wildcopy() to the broken gcc version. See
  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81388.

ZSTD_copy8() and ZSTD_wildcopy() are in the core of the zstd hot loop.
So outlining these calls to memcpy(), and having an extra branch are very
detrimental to performance.

Signed-off-by: Nick Terrell <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Tested-by: Sedat Dilek <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
- Add unzstd() and the zstd decompress interface.

- Add zstd support to decompress_method().

The decompress_method() and unzstd() functions are used to decompress
the initramfs and the initrd. The __decompress() function is used in
the preboot environment to decompress a zstd compressed kernel.

The zstd decompression function allows the input and output buffers to
overlap because that is used by x86 kernel decompression.

Signed-off-by: Nick Terrell <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Tested-by: Sedat Dilek <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
The zstd decompression code, as it is right now, will most likely fail
on 32-bit systems, as the default output buffer size causes the buffer's
end address to overflow.

Address this issue by setting a sane default to the default output size,
with a value that won't overflow the buffer's end address.

Signed-off-by: Paul Cercueil <[email protected]>
Reviewed-by: Nick Terrell <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>
These constants are really used internally by zstd and including
linux/zstd.h into users results in the following warnings:

In file included from fs/btrfs/zstd.c:19:
./include/linux/zstd.h:798:21: warning: ‘ZSTD_skippableHeaderSize’ defined but not used [-Wunused-const-variable=]
  798 | static const size_t ZSTD_skippableHeaderSize = 8;
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/zstd.h:796:21: warning: ‘ZSTD_frameHeaderSize_max’ defined but not used [-Wunused-const-variable=]
  796 | static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/zstd.h:795:21: warning: ‘ZSTD_frameHeaderSize_min’ defined but not used [-Wunused-const-variable=]
  795 | static const size_t ZSTD_frameHeaderSize_min = ZSTD_FRAMEHEADERSIZE_MIN;
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/zstd.h:794:21: warning: ‘ZSTD_frameHeaderSize_prefix’ defined but not used [-Wunused-const-variable=]
  794 | static const size_t ZSTD_frameHeaderSize_prefix = 5;

So fix those warnings by turning the constants into defines.

Reviewed-by: Nick Terrell <[email protected]>
Signed-off-by: Nikolay Borisov <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
This patch:
- Moves `include/linux/zstd.h` -> `include/linux/zstd_lib.h`
- Updates modified zstd headers to yearless copyright
- Adds a new API in `include/linux/zstd.h` that is functionally
  equivalent to the in-use subset of the current API. Functions are
  renamed to avoid symbol collisions with zstd, to make it clear it is
  not the upstream zstd API, and to follow the kernel style guide.
- Updates all callers to use the new API.

There are no functional changes in this patch. Since there are no
functional change, I felt it was okay to update all the callers in a
single patch. Once the API is approved, the callers are mechanically
changed.

This patch is preparing for the 3rd patch in this series, which updates
zstd to version 1.4.10. Since the upstream zstd API is no longer exposed
to callers, the update can happen transparently.

Signed-off-by: Nick Terrell <[email protected]>
Tested By: Paul Jones <[email protected]>
Tested-by: Oleksandr Natalenko <[email protected]>
Tested-by: Sedat Dilek <[email protected]> # LLVM/Clang v13.0.0 on x86-64
Tested-by: Jean-Denis Girard <[email protected]>
Adds decompress_sources.h which includes every .c file necessary for
zstd decompression. This is used in decompress_unzstd.c so the internal
structure of the library isn't exposed.

This allows us to upgrade the zstd library version without modifying any
callers. Instead we just need to update decompress_sources.h.

Signed-off-by: Nick Terrell <[email protected]>
Tested By: Paul Jones <[email protected]>
Tested-by: Oleksandr Natalenko <[email protected]>
Tested-by: Sedat Dilek <[email protected]> # LLVM/Clang v13.0.0 on x86-64
Tested-by: Jean-Denis Girard <[email protected]>
Upgrade to the latest upstream zstd version 1.4.10.

This patch is 100% generated from upstream zstd commit 20821a46f412 [0].

This patch is very large because it is transitioning from the custom
kernel zstd to using upstream directly. The new zstd follows upstreams
file structure which is different. Future update patches will be much
smaller because they will only contain the changes from one upstream
zstd release.

As an aid for review I've created a commit [1] that shows the diff
between upstream zstd as-is (which doesn't compile), and the zstd
code imported in this patch. The verion of zstd in this patch is
generated from upstream with changes applied by automation to replace
upstreams libc dependencies, remove unnecessary portability macros,
replace `/**` comments with `/*` comments, and use the kernel's xxhash
instead of bundling it.

The benefits of this patch are as follows:
1. Using upstream directly with automated script to generate kernel
   code. This allows us to update the kernel every upstream release, so
   the kernel gets the latest bug fixes and performance improvements,
   and doesn't get 3 years out of date again. The automation and the
   translated code are tested every upstream commit to ensure it
   continues to work.
2. Upgrades from a custom zstd based on 1.3.1 to 1.4.10, getting 3 years
   of performance improvements and bug fixes. On x86_64 I've measured
   15% faster BtrFS and SquashFS decompression+read speeds, 35% faster
   kernel decompression, and 30% faster ZRAM decompression+read speeds.
3. Zstd-1.4.10 supports negative compression levels, which allow zstd to
   match or subsume lzo's performance.
4. Maintains the same kernel-specific wrapper API, so no callers have to
   be modified with zstd version updates.

One concern that was brought up was stack usage. Upstream zstd had
already removed most of its heavy stack usage functions, but I just
removed the last functions that allocate arrays on the stack. I've
measured the high water mark for both compression and decompression
before and after this patch. Decompression is approximately neutral,
using about 1.2KB of stack space. Compression levels up to 3 regressed
from 1.4KB -> 1.6KB, and higher compression levels regressed from 1.5KB
-> 2KB. We've added unit tests upstream to prevent further regression.
I believe that this is a reasonable increase, and if it does end up
causing problems, this commit can be cleanly reverted, because it only
touches zstd.

I chose the bulk update instead of replaying upstream commits because
there have been ~3500 upstream commits since the 1.3.1 release, zstd
wasn't ready to be used in the kernel as-is before a month ago, and not
all upstream zstd commits build. The bulk update preserves bisectablity
because bugs can be bisected to the zstd version update. At that point
the update can be reverted, and we can work with upstream to find and
fix the bug.

Note that upstream zstd release 1.4.10 doesn't exist yet. I have cut a
staging branch at 20821a46f412 [0] and will apply any changes requested
to the staging branch. Once we're ready to merge this update I will cut
a zstd release at the commit we merge, so we have a known zstd release
in the kernel.

The implementation of the kernel API is contained in
zstd_compress_module.c and zstd_decompress_module.c.

[0] facebook/zstd@20821a4
[1] terrelln/linux@e0fa481

Signed-off-by: Nick Terrell <[email protected]>
Tested By: Paul Jones <[email protected]>
Tested-by: Oleksandr Natalenko <[email protected]>
Tested-by: Sedat Dilek <[email protected]> # LLVM/Clang v13.0.0 on x86-64
Tested-by: Jean-Denis Girard <[email protected]>
A new warning in clang warns that there is an instance where boolean
expressions are being used with bitwise operators instead of logical
ones:

lib/zstd/decompress/huf_decompress.c:890:25: warning: use of bitwise '&' with boolean operands [-Wbitwise-instead-of-logical]
                       (BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished)
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

zstd does this frequently to help with performance, as logical operators
have branches whereas bitwise ones do not.

To fix this warning in other cases, the expressions were placed on
separate lines with the '&=' operator; however, this particular instance
was moved away from that so that it could be surrounded by LIKELY, which
is a macro for __builtin_expect(), to help with a performance
regression, according to upstream zstd pull #1973.

Aside from switching to logical operators, which is likely undesirable
in this instance, or disabling the warning outright, the solution is
casting one of the expressions to an integer type to make it clear to
clang that the author knows what they are doing. Add a cast to U32 to
silence the warning. The first U32 cast is to silence an instance of
-Wshorten-64-to-32 because __builtin_expect() returns long so it cannot
be moved.

Link: ClangBuiltLinux/linux#1486
Link: facebook/zstd#1973
Reported-by: Nick Desaulniers <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Nick Terrell <[email protected]>
The variable `litLengthSum` is only used by an `assert()`, so when
asserts are disabled the compiler doesn't see any usage and warns.

This issue is already fixed upstream by PR #2838 [0]. It was reported
by the Kernel test robot in [1].

Another approach would be to change zstd's disabled `assert()`
definition to use the argument in a disabled branch, instead of
ignoring the argument. I've avoided this approach because there are
some small changes necessary to get zstd to build, and I would
want to thoroughly re-test for performance, since that is slightly
changing the code in every function in zstd. It seems like a
trivial change, but some functions are pretty sensitive to small
changes. However, I think it is a valid approach that I would
like to see upstream take, so I've opened Issue #2868 to attempt
this upstream.

Lastly, I've chosen not to use __maybe_unused because all code
in lib/zstd/ must eventually be upstreamed. Upstream zstd can't
use __maybe_unused because it isn't portable across all compilers.

[0] facebook/zstd#2838
[1] https://lore.kernel.org/linux-mm/[email protected]/T/
[2] facebook/zstd#2868

Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Nick Terrell <[email protected]>
`zstd_opt.c` contains the match finder for the highest compression
levels. These levels are already very slow, and are unlikely to be used
in the kernel. If they are used, they shouldn't be used in latency
sensitive workloads, so slowing them down shouldn't be a big deal.

This saves 188 KB of the 288 KB regression reported by Geert Uytterhoeven [0].
I've also opened an issue upstream [1] so that we can properly tackle
the code size issue in `zstd_opt.c` for all users, and can hopefully
remove this hack in the next zstd version we import.

Bloat-o-meter output on x86-64:

```
> ../scripts/bloat-o-meter vmlinux.old vmlinux
add/remove: 6/5 grow/shrink: 1/9 up/down: 16673/-209939 (-193266)
Function                                     old     new   delta
ZSTD_compressBlock_opt_generic.constprop       -    7559   +7559
ZSTD_insertBtAndGetAllMatches                  -    6304   +6304
ZSTD_insertBt1                                 -    1731   +1731
ZSTD_storeSeq                                  -     693    +693
ZSTD_BtGetAllMatches                           -     255    +255
ZSTD_updateRep                                 -     128    +128
ZSTD_updateTree                               96      99      +3
ZSTD_insertAndFindFirstIndexHash3             81       -     -81
ZSTD_setBasePrices.constprop                  98       -     -98
ZSTD_litLengthPrice.constprop                138       -    -138
ZSTD_count                                   362     181    -181
ZSTD_count_2segments                        1407     938    -469
ZSTD_insertBt1.constprop                    2689       -   -2689
ZSTD_compressBlock_btultra2                19990     423  -19567
ZSTD_compressBlock_btultra                 19633      15  -19618
ZSTD_initStats_ultra                       19825       -  -19825
ZSTD_compressBlock_btopt                   20374      12  -20362
ZSTD_compressBlock_btopt_extDict           29984      12  -29972
ZSTD_compressBlock_btultra_extDict         30718      15  -30703
ZSTD_compressBlock_btopt_dictMatchState    32689      12  -32677
ZSTD_compressBlock_btultra_dictMatchState   33574      15  -33559
Total: Before=6611828, After=6418562, chg -2.92%
```

[0] https://lkml.org/lkml/2021/11/14/189
[1] facebook/zstd#2862

Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/

Reported-by: Geert Uytterhoeven <[email protected]>
Tested-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Nick Terrell <[email protected]>
After the update to zstd-1.4.10 passing -O3 is no longer necessary to
get good performance from zstd. Using the default optimization level -O2
is sufficient to get good performance.

I've measured no significant change to compression speed, and a ~1%
decompression speed loss, which is acceptable.

This fixes the reported parisc -Wframe-larger-than=1536 errors [0]. The
gcc-8-hppa-linux-gnu compiler performed very poorly with -O3, generating
stacks that are ~3KB. With -O2 these same functions generate stacks in
the < 100B, completely fixing the problem. Function size deltas are
listed below:

ZSTD_compressBlock_fast_extDict_generic: 3800 -> 68
ZSTD_compressBlock_fast: 2216 -> 40
ZSTD_compressBlock_fast_dictMatchState: 1848 ->  64
ZSTD_compressBlock_doubleFast_extDict_generic: 3744 -> 76
ZSTD_fillDoubleHashTable: 3252 -> 0
ZSTD_compressBlock_doubleFast: 5856 -> 36
ZSTD_compressBlock_doubleFast_dictMatchState: 5380 -> 84
ZSTD_copmressBlock_lazy2: 2420 -> 72

Additionally, this improves the reported code bloat [1]. With gcc-11
bloat-o-meter shows an 80KB code size improvement:

```
> ../scripts/bloat-o-meter vmlinux.old vmlinux
add/remove: 31/8 grow/shrink: 24/155 up/down: 25734/-107924 (-82190)
Total: Before=6418562, After=6336372, chg -1.28%
```

Compared to before the zstd-1.4.10 update we see a total code size
regression of 105KB, down from 374KB at v5.16-rc1:

```
> ../scripts/bloat-o-meter vmlinux.old vmlinux
add/remove: 292/62 grow/shrink: 56/88 up/down: 235009/-127487 (107522)
Total: Before=6228850, After=6336372, chg +1.73%
```

[0] https://lkml.org/lkml/2021/11/15/710
[1] https://lkml.org/lkml/2021/11/14/189

Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/

Reported-by: Geert Uytterhoeven <[email protected]>
Tested-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Nick Terrell <[email protected]>
Level 1 is faster than level 3, and the compression ratio is very similar to level 3.
@urain39 urain39 changed the title backport new zstd kernel module (tested) m1721: backport new zstd from linux mainline Jul 27, 2022
tdrkDev pushed a commit that referenced this pull request Oct 9, 2022
commit 38c9c22a85aeed28d0831f230136e9cf6fa2ed44 upstream.

Syzkaller reported use-after-free bug as follows:

==================================================================
BUG: KASAN: use-after-free in ntfs_ucsncmp+0x123/0x130
Read of size 2 at addr ffff8880751acee8 by task a.out/879

CPU: 7 PID: 879 Comm: a.out Not tainted 5.19.0-rc4-next-20220630-00001-gcc5218c8bd2c-dirty #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x1c0/0x2b0
 print_address_description.constprop.0.cold+0xd4/0x484
 print_report.cold+0x55/0x232
 kasan_report+0xbf/0xf0
 ntfs_ucsncmp+0x123/0x130
 ntfs_are_names_equal.cold+0x2b/0x41
 ntfs_attr_find+0x43b/0xb90
 ntfs_attr_lookup+0x16d/0x1e0
 ntfs_read_locked_attr_inode+0x4aa/0x2360
 ntfs_attr_iget+0x1af/0x220
 ntfs_read_locked_inode+0x246c/0x5120
 ntfs_iget+0x132/0x180
 load_system_files+0x1cc6/0x3480
 ntfs_fill_super+0xa66/0x1cf0
 mount_bdev+0x38d/0x460
 legacy_get_tree+0x10d/0x220
 vfs_get_tree+0x93/0x300
 do_new_mount+0x2da/0x6d0
 path_mount+0x496/0x19d0
 __x64_sys_mount+0x284/0x300
 do_syscall_64+0x3b/0xc0
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f3f2118d9ea
Code: 48 8b 0d a9 f4 0b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 76 f4 0b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffc269deac8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3f2118d9ea
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffc269dec00
RBP: 00007ffc269dec80 R08: 00007ffc269deb00 R09: 00007ffc269dec44
R10: 0000000000000000 R11: 0000000000000202 R12: 000055f81ab1d220
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

The buggy address belongs to the physical page:
page:0000000085430378 refcount:1 mapcount:1 mapping:0000000000000000 index:0x555c6a81d pfn:0x751ac
memcg:ffff888101f7e180
anon flags: 0xfffffc00a0014(uptodate|lru|mappedtodisk|swapbacked|node=0|zone=1|lastcpupid=0x1fffff)
raw: 000fffffc00a0014 ffffea0001bf2988 ffffea0001de2448 ffff88801712e201
raw: 0000000555c6a81d 0000000000000000 0000000100000000 ffff888101f7e180
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880751acd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880751ace00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880751ace80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                          ^
 ffff8880751acf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880751acf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

The reason is that struct ATTR_RECORD->name_offset is 6485, end address of
name string is out of bounds.

Fix this by adding sanity check on end address of attribute name string.

[[email protected]: coding-style cleanups]
[[email protected]: cleanup suggested by Hawkins Jiawei]
  Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: ChenXiaoSong <[email protected]>
Signed-off-by: Hawkins Jiawei <[email protected]>
Cc: Anton Altaparmakov <[email protected]>
Cc: ChenXiaoSong <[email protected]>
Cc: Yongqiang Liu <[email protected]>
Cc: Zhang Yi <[email protected]>
Cc: Zhang Xiaoxu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
tdrkDev pushed a commit that referenced this pull request Oct 9, 2022
…loc()

commit d29f59051d3a07b81281b2df2b8c9dfe4716067f upstream.

The voice allocator sometimes begins allocating from near the end of the
array and then wraps around, however snd_emu10k1_pcm_channel_alloc()
accesses the newly allocated voices as if it never wrapped around.

This results in out of bounds access if the first voice has a high enough
index so that first_voice + requested_voice_count > NUM_G (64).
The more voices are requested, the more likely it is for this to occur.

This was initially discovered using PipeWire, however it can be reproduced
by calling aplay multiple times with 16 channels:
aplay -r 48000 -D plughw:CARD=Live,DEV=3 -c 16 /dev/zero

UBSAN: array-index-out-of-bounds in sound/pci/emu10k1/emupcm.c:127:40
index 65 is out of range for type 'snd_emu10k1_voice [64]'
CPU: 1 PID: 31977 Comm: aplay Tainted: G        W IOE      6.0.0-rc2-emu10k1+ #7
Hardware name: ASUSTEK COMPUTER INC P5W DH Deluxe/P5W DH Deluxe, BIOS 3002    07/22/2010
Call Trace:
<TASK>
dump_stack_lvl+0x49/0x63
dump_stack+0x10/0x16
ubsan_epilogue+0x9/0x3f
__ubsan_handle_out_of_bounds.cold+0x44/0x49
snd_emu10k1_playback_hw_params+0x3bc/0x420 [snd_emu10k1]
snd_pcm_hw_params+0x29f/0x600 [snd_pcm]
snd_pcm_common_ioctl+0x188/0x1410 [snd_pcm]
? exit_to_user_mode_prepare+0x35/0x170
? do_syscall_64+0x69/0x90
? syscall_exit_to_user_mode+0x26/0x50
? do_syscall_64+0x69/0x90
? exit_to_user_mode_prepare+0x35/0x170
snd_pcm_ioctl+0x27/0x40 [snd_pcm]
__x64_sys_ioctl+0x95/0xd0
do_syscall_64+0x5c/0x90
? do_syscall_64+0x69/0x90
? do_syscall_64+0x69/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Signed-off-by: Tasos Sahanidis <[email protected]>
Cc: <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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8 participants