16238415eb
When the sum of fl->fl_start and l->l_len overflows, UBSAN shows the following warning: UBSAN: Undefined behaviour in fs/locks.c:482:29 signed integer overflow: 2 + 9223372036854775806 cannot be represented in type 'long long int' Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xe4/0x14e lib/dump_stack.c:118 ubsan_epilogue+0xe/0x81 lib/ubsan.c:161 handle_overflow+0x193/0x1e2 lib/ubsan.c:192 flock64_to_posix_lock fs/locks.c:482 [inline] flock_to_posix_lock+0x595/0x690 fs/locks.c:515 fcntl_setlk+0xf3/0xa90 fs/locks.c:2262 do_fcntl+0x456/0xf60 fs/fcntl.c:387 __do_sys_fcntl fs/fcntl.c:483 [inline] __se_sys_fcntl fs/fcntl.c:468 [inline] __x64_sys_fcntl+0x12d/0x180 fs/fcntl.c:468 do_syscall_64+0xc8/0x5a0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fix it by parenthesizing 'l->l_len - 1'. Signed-off-by: Luo Meng <luomeng12@huawei.com> Signed-off-by: Jeff Layton <jlayton@kernel.org>
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.