kernel/linux.git/Documentation/process, branch v5.15.99

overflow: Implement size_t saturating arithmetic helpers

2022-12-31T12:14:33+00:00

[ Upstream commit e1be43d9b5d0d1310dbd90185a8e5c7145dde40f ] In order to perform more open-coded replacements of common allocation size arithmetic, the kernel needs saturating (SIZE_MAX) helpers for multiplication, addition, and subtraction. For example, it is common in allocators, especially on realloc, to add to an existing size: p = krealloc(map->patch, sizeof(struct reg_sequence) * (map->patch_regs + num_regs), GFP_KERNEL); There is no existing saturating replacement for this calculation, and just leaving the addition open coded inside array_size() could potentially overflow as well. For example, an overflow in an expression for a size_t argument might wrap to zero: array_size(anything, something_at_size_max + 1) == 0 Introduce size_mul(), size_add(), and size_sub() helpers that implicitly promote arguments to size_t and saturated calculations for use in allocations. With these helpers it is also possible to redefine array_size(), array3_size(), flex_array_size(), and struct_size() in terms of the new helpers. As with the check_*_overflow() helpers, the new helpers use __must_check, though what is really desired is a way to make sure that assignment is only to a size_t lvalue. Without this, it's still possible to introduce overflow/underflow via type conversion (i.e. from size_t to int). Enforcing this will currently need to be left to static analysis or future use of -Wconversion. Additionally update the overflow unit tests to force runtime evaluation for the pathological cases. Cc: Rasmus Villemoes Cc: Gustavo A. R. Silva Cc: Nathan Chancellor Cc: Jason Gunthorpe Cc: Nick Desaulniers Cc: Leon Romanovsky Cc: Keith Busch Cc: Len Baker Signed-off-by: Kees Cook Stable-dep-of: e001e6086939 ("fs/ntfs3: Harden against integer overflows") Signed-off-by: Sasha Levin

docs: update mediator contact information in CoC doc

2022-11-26T08:24:48+00:00

commit 5fddf8962b429b8303c4a654291ecb6e61a7d747 upstream. Update mediator contact information in CoC interpretation document. Cc: Signed-off-by: Shuah Khan Link: https://lore.kernel.org/r/20221011171417.34286-1-skhan@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

docs: update mediator information in CoC docs

2022-10-12T07:53:26+00:00

commit 8bfdfa0d6b929ede7b6189e0e546ceb6a124d05d upstream. Update mediator information in the CoC interpretation document. Signed-off-by: Shuah Khan Link: https://lore.kernel.org/r/20220901212319.56644-1-skhan@linuxfoundation.org Cc: stable@vger.kernel.org Signed-off-by: Jonathan Corbet Signed-off-by: Greg Kroah-Hartman

docs: submitting-patches: Fix crossref to 'The canonical patch format'

2022-06-06T06:43:41+00:00

commit 6d5aa418b3bd42cdccc36e94ee199af423ef7c84 upstream. The reference to `explicit_in_reply_to` is pointless as when the reference was added in the form of "#15" [1], Section 15) was "The canonical patch format". The reference of "#15" had not been properly updated in a couple of reorganizations during the plain-text SubmittingPatches era. Fix it by using `the_canonical_patch_format`. [1]: 2ae19acaa50a ("Documentation: Add "how to write a good patch summary" to SubmittingPatches") Signed-off-by: Akira Yokosawa Fixes: 5903019b2a5e ("Documentation/SubmittingPatches: convert it to ReST markup") Fixes: 9b2c76777acc ("Documentation/SubmittingPatches: enrich the Sphinx output") Cc: Jonathan Corbet Cc: Mauro Carvalho Chehab Cc: stable@vger.kernel.org # v4.9+ Link: https://lore.kernel.org/r/64e105a5-50be-23f2-6cae-903a2ea98e18@gmail.com Signed-off-by: Jonathan Corbet Signed-off-by: Greg Kroah-Hartman

Documentation: update stable tree link

2022-04-08T12:22:51+00:00

commit 555d44932c67e617d89bc13c81c7efac5b51fcfa upstream. The link to stable tree is redirected to https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git. Update accordingly. Cc: Greg Kroah-Hartman Cc: Sasha Levin Cc: Jonathan Corbet Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Bagas Sanjaya Link: https://lore.kernel.org/r/20220314113329.485372-6-bagasdotme@gmail.com Signed-off-by: Greg Kroah-Hartman

Documentation: add link to stable release candidate tree

2022-04-08T12:22:51+00:00

commit 587d39b260c4d090166314d64be70b1f6a26b0b5 upstream. There is also stable release candidate tree. Mention it, however with a warning that the tree is for testing purposes. Cc: Greg Kroah-Hartman Cc: Sasha Levin Cc: Jonathan Corbet Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Bagas Sanjaya Link: https://lore.kernel.org/r/20220314113329.485372-5-bagasdotme@gmail.com Signed-off-by: Greg Kroah-Hartman

Merge branch 'gcc-min-version-5.1' (make gcc-5.1 the minimum version)

2021-09-13T17:43:04+00:00

Merge patch series from Nick Desaulniers to update the minimum gcc version to 5.1. This is some of the left-overs from the merge window that I didn't want to deal with yesterday, so it comes in after -rc1 but was sent before. Gcc-4.9 support has been an annoyance for some time, and with -Werror I had the choice of applying a fairly big patch from Kees Cook to remove a fair number of initializer warnings (still leaving some), or this patch series from Nick that just removes the source of the problem. The initializer cleanups might still be worth it regardless, but honestly, I preferred just tackling the problem with gcc-4.9 head-on. We've been more aggressiuve about no longer having to care about compilers that were released a long time ago, and I think it's been a good thing. I added a couple of patches on top to sort out a few left-overs now that we no longer support gcc-4.x. As noted by Arnd, as a result of this minimum compiler version upgrade we can probably change our use of '--std=gnu89' to '--std=gnu11', and finally start using local loop declarations etc. But this series does _not_ yet do that. Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/ Link: https://lore.kernel.org/lkml/CAK7LNASs6dvU6D3jL2GG3jW58fXfaj6VNOe55NJnTB8UPuk2pA@mail.gmail.com/ Link: https://github.com/ClangBuiltLinux/linux/issues/1438 * emailed patches from Nick Desaulniers : Drop some straggling mentions of gcc-4.9 as being stale compiler_attributes.h: drop __has_attribute() support for gcc4 vmlinux.lds.h: remove old check for GCC 4.9 compiler-gcc.h: drop checks for older GCC versions Makefile: drop GCC < 5 -fno-var-tracking-assignments workaround arm64: remove GCC version check for ARCH_SUPPORTS_INT128 powerpc: remove GCC version check for UPD_CONSTR riscv: remove Kconfig check for GCC version for ARCH_RV64I Kconfig.debug: drop GCC 5+ version check for DWARF5 mm/ksm: remove old GCC 4.9+ check compiler.h: drop fallback overflow checkers Documentation: raise minimum supported version of GCC to 5.1

Documentation: raise minimum supported version of GCC to 5.1

2021-09-13T17:18:28+00:00

commit fad7cd3310db ("nbd: add the check to prevent overflow in __nbd_ioctl()") raised an issue from the fallback helpers added in commit f0907827a8a9 ("compiler.h: enable builtin overflow checkers and add fallback code") Specifically, the helpers for checking whether the results of a multiplication overflowed (__unsigned_mul_overflow, __signed_add_overflow) use the division operator when !COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW. This is problematic for 64b operands on 32b hosts. Also, because the macro is type agnostic, it is very difficult to write a similarly type generic macro that dispatches to one of: * div64_s64 * div64_u64 * div_s64 * div_u64 Raising the minimum supported versions allows us to remove all of the fallback helpers for !COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW, instead dispatching the compiler builtins. arm64 has already raised the minimum supported GCC version to 5.1, do this for all targets now. See the link below for the previous discussion. Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/ Link: https://lore.kernel.org/lkml/CAK7LNASs6dvU6D3jL2GG3jW58fXfaj6VNOe55NJnTB8UPuk2pA@mail.gmail.com/ Link: https://github.com/ClangBuiltLinux/linux/issues/1438 Reported-by: Stephen Rothwell Reported-by: Nathan Chancellor Suggested-by: Rasmus Villemoes Signed-off-by: Nick Desaulniers Reviewed-by: Kees Cook Reviewed-by: Nathan Chancellor Signed-off-by: Linus Torvalds

Documentation/process/maintainer-pgp-guide: Replace broken link to PGP path finder

2021-08-24T19:23:21+00:00

PGP pathfinder[1], which is suggested for finding a trust path to unknown PGP keys by 'maintainer-pgp-guide.rst', is not working now. This commit replaces it with other available tools. [1] https://pgp.cs.uu.nl/ Signed-off-by: SeongJae Park Reviewed-by: Konstantin Ryabitsev Link: https://lore.kernel.org/r/20210812095030.4704-2-sj38.park@gmail.com Signed-off-by: Jonathan Corbet

Documentation: Update details of The Linux Kernel Module Programming Guide

2021-08-20T23:05:45+00:00

Recently, the content and examples of the book "The Linux Kernel Module Programming Guide" are being actively maintained and added on Github[1]. Currently, the book is being regularly built into webpage and pdf file using Github static page[2]. [1]: https://github.com/sysprog21/lkmpg [2]: https://sysprog21.github.io/lkmpg/ Signed-off-by: Chun-Hung Tseng Link: https://lore.kernel.org/r/20210820222152.971174-1-henrybear327@gmail.com [jc: fixed docs-build warnings] Signed-off-by: Jonathan Corbet