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Andrey Ryabinin 6aaa31aeb9 ubsan: remove overflow checks
Since GCC 8.0 -fsanitize=signed-integer-overflow doesn't work with
-fwrapv.  -fwrapv makes signed overflows defines and GCC essentially
disables ubsan checks.  On GCC < 8.0 -fwrapv doesn't have influence on
-fsanitize=signed-integer-overflow setting, so it kinda works but
generates false-positves and violates uaccess rules:

lib/iov_iter.o: warning: objtool: iovec_from_user()+0x22d: call to
__ubsan_handle_add_overflow() with UACCESS enabled

Disable signed overflow checks to avoid these problems.  Remove unsigned
overflow checks as well.  Unsigned overflow appeared as side effect of
commit cdf8a76fda ("ubsan: move cc-option tests into Kconfig"), but it
never worked (kernel doesn't boot).  And unsigned overflows are allowed by
C standard, so it just pointless.

Link: https://lkml.kernel.org/r/20210209232348.20510-1-ryabinin.a.a@gmail.com
Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-26 09:41:05 -08:00
Documentation seq_file: document how per-entry resources are managed. 2021-02-26 09:41:05 -08:00
LICENSES
arch x86: fix seq_file iteration for pat/memtype.c 2021-02-26 09:41:05 -08:00
block
certs
crypto
drivers treewide: Miguel has moved 2021-02-26 09:41:03 -08:00
fs fs/coredump: use kmap_local_page() 2021-02-26 09:41:05 -08:00
include kgdb: fix to kill breakpoints on initmem after boot 2021-02-26 09:41:05 -08:00
init kgdb: fix to kill breakpoints on initmem after boot 2021-02-26 09:41:05 -08:00
ipc
kernel kgdb: fix to kill breakpoints on initmem after boot 2021-02-26 09:41:05 -08:00
lib ubsan: remove overflow checks 2021-02-26 09:41:05 -08:00
mm kasan: clarify that only first bug is reported in HW_TAGS 2021-02-26 09:41:03 -08:00
net
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scripts ubsan: remove overflow checks 2021-02-26 09:41:05 -08:00
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usr Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
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MAINTAINERS MAINTAINERS: add uapi directories to API/ABI section 2021-02-26 09:41:04 -08:00
Makefile Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
README

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.