Patch series "arm64: untag user pointers passed to the kernel", v19.
=== Overview
arm64 has a feature called Top Byte Ignore, which allows to embed pointer
tags into the top byte of each pointer. Userspace programs (such as
HWASan, a memory debugging tool [1]) might use this feature and pass
tagged user pointers to the kernel through syscalls or other interfaces.
Right now the kernel is already able to handle user faults with tagged
pointers, due to these patches:
1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a
tagged pointer")
2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged
pointers")
3. 276e9327 ("arm64: entry: improve data abort handling of tagged
pointers")
This patchset extends tagged pointer support to syscall arguments.
As per the proposed ABI change [3], tagged pointers are only allowed to be
passed to syscalls when they point to memory ranges obtained by anonymous
mmap() or sbrk() (see the patchset [3] for more details).
For non-memory syscalls this is done by untaging user pointers when the
kernel performs pointer checking to find out whether the pointer comes
from userspace (most notably in access_ok). The untagging is done only
when the pointer is being checked, the tag is preserved as the pointer
makes its way through the kernel and stays tagged when the kernel
dereferences the pointer when perfoming user memory accesses.
The mmap and mremap (only new_addr) syscalls do not currently accept
tagged addresses. Architectures may interpret the tag as a background
colour for the corresponding vma.
Other memory syscalls (mprotect, etc.) don't do user memory accesses but
rather deal with memory ranges, and untagged pointers are better suited to
describe memory ranges internally. Thus for memory syscalls we untag
pointers completely when they enter the kernel.
=== Other approaches
One of the alternative approaches to untagging that was considered is to
completely strip the pointer tag as the pointer enters the kernel with
some kind of a syscall wrapper, but that won't work with the countless
number of different ioctl calls. With this approach we would need a
custom wrapper for each ioctl variation, which doesn't seem practical.
An alternative approach to untagging pointers in memory syscalls prologues
is to inspead allow tagged pointers to be passed to find_vma() (and other
vma related functions) and untag them there. Unfortunately, a lot of
find_vma() callers then compare or subtract the returned vma start and end
fields against the pointer that was being searched. Thus this approach
would still require changing all find_vma() callers.
=== Testing
The following testing approaches has been taken to find potential issues
with user pointer untagging:
1. Static testing (with sparse [2] and separately with a custom static
analyzer based on Clang) to track casts of __user pointers to integer
types to find places where untagging needs to be done.
2. Static testing with grep to find parts of the kernel that call
find_vma() (and other similar functions) or directly compare against
vm_start/vm_end fields of vma.
3. Static testing with grep to find parts of the kernel that compare
user pointers with TASK_SIZE or other similar consts and macros.
4. Dynamic testing: adding BUG_ON(has_tag(addr)) to find_vma() and running
a modified syzkaller version that passes tagged pointers to the kernel.
Based on the results of the testing the requried patches have been added
to the patchset.
=== Notes
This patchset is meant to be merged together with "arm64 relaxed ABI" [3].
This patchset is a prerequisite for ARM's memory tagging hardware feature
support [4].
This patchset has been merged into the Pixel 2 & 3 kernel trees and is
now being used to enable testing of Pixel phones with HWASan.
Thanks!
[1] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html
[2] 5f960cb10f
[3] https://lkml.org/lkml/2019/6/12/745
[4] https://community.arm.com/processors/b/blog/posts/arm-a-profile-architecture-2018-developments-armv85a
This patch (of 11)
This patch is a part of a series that extends kernel ABI to allow to pass
tagged user pointers (with the top byte set to something else other than
0x00) as syscall arguments.
strncpy_from_user and strnlen_user accept user addresses as arguments, and
do not go through the same path as copy_from_user and others, so here we
need to handle the case of tagged user addresses separately.
Untag user pointers passed to these functions.
Note, that this patch only temporarily untags the pointers to perform
validity checks, but then uses them as is to perform user memory accesses.
[andreyknvl@google.com: fix sparc4 build]
Link: http://lkml.kernel.org/r/CAAeHK+yx4a-P0sDrXTUxMvO2H0CJZUFPffBrg_cU7oJOZyC7ew@mail.gmail.com
Link: http://lkml.kernel.org/r/c5a78bcad3e94d6cda71fcaa60a423231ae71e4c.1563904656.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The original clean up of "cut here" missed the WARN_ON() case (that does
not have a printk message), which was fixed recently by adding an explicit
printk of "cut here". This had the downside of adding a printk() to every
WARN_ON() caller, which reduces the utility of using an instruction
exception to streamline the resulting code. By making this a new BUGFLAG,
all of these can be removed and "cut here" can be handled by the exception
handler.
This was very pronounced on PowerPC, but the effect can be seen on x86 as
well. The resulting text size of a defconfig build shows some small
savings from this patch:
text data bss dec hex filename
19691167 5134320 1646664 26472151 193eed7 vmlinux.before
19676362 5134260 1663048 26473670 193f4c6 vmlinux.after
This change also opens the door for creating something like BUG_MSG(),
where a custom printk() before issuing BUG(), without confusing the "cut
here" line.
Link: http://lkml.kernel.org/r/201908200943.601DD59DCE@keescook
Fixes: 6b15f678fb ("include/asm-generic/bug.h: fix "cut here" for WARN_ON for __WARN_TAINT architectures")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Drew Davenport <ddavenport@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Clean up WARN() "cut here" handling", v2.
Christophe Leroy noticed that the fix for missing "cut here" in the WARN()
case was adding explicit printk() calls instead of teaching the exception
handler to add it. This refactors the bug/warn infrastructure to pass
this information as a new BUGFLAG.
Longer details repeated from the last patch in the series:
bug: move WARN_ON() "cut here" into exception handler
The original cleanup of "cut here" missed the WARN_ON() case (that does
not have a printk message), which was fixed recently by adding an explicit
printk of "cut here". This had the downside of adding a printk() to every
WARN_ON() caller, which reduces the utility of using an instruction
exception to streamline the resulting code. By making this a new BUGFLAG,
all of these can be removed and "cut here" can be handled by the exception
handler.
This was very pronounced on PowerPC, but the effect can be seen on x86 as
well. The resulting text size of a defconfig build shows some small
savings from this patch:
text data bss dec hex filename
19691167 5134320 1646664 26472151 193eed7 vmlinux.before
19676362 5134260 1663048 26473670 193f4c6 vmlinux.after
This change also opens the door for creating something like BUG_MSG(),
where a custom printk() before issuing BUG(), without confusing the "cut
here" line.
This patch (of 7):
There's no reason to have specialized helpers for passing the warn taint
down to __warn(). Consolidate and refactor helper macros, removing
__WARN_printf() and warn_slowpath_fmt_taint().
Link: http://lkml.kernel.org/r/20190819234111.9019-2-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Drew Davenport <ddavenport@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some systems (like Chrome OS) may use "split debug" for kernel modules.
That means that the debug symbols are in a different file than the main
elf file. Let's handle that by also searching for debug symbols that end
in ".ko.debug".
This is a packaging topic. You can take a normal elf file and split the
debug out of it using objcopy. Try "man objcopy" and then take a look at
the "--only-keep-debug" option. It'll give you a whole recipe for doing
splitdebug. The suffix used for the debug symbols is arbitrary. If
people have other another suffix besides ".ko.debug" then we could
presumably support that too...
For portage (which is the packaging system used by Chrome OS) split debug
is supported by default (and the suffix is .ko.debug). ...and so in
Chrome OS we always get the installed elf files stripped and then the
symbols stashed away.
At the moment we don't actually use the normal portage magic to do this
for the kernel though since it affects our ability to get good stack dumps
in the kernel. We instead pass a script as "strip" [1].
[1] https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/refs/heads/master/eclass/cros-kernel/strip_splitdebug
Link: http://lkml.kernel.org/r/20190730234052.148744-1-dianders@chromium.org
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Right now kgdb/kdb hooks up to debug panics by registering for the panic
notifier. This works OK except that it means that kgdb/kdb gets called
_after_ the CPUs in the system are taken offline. That means that if
anything important was happening on those CPUs (like something that might
have contributed to the panic) you can't debug them.
Specifically I ran into a case where I got a panic because a task was
"blocked for more than 120 seconds" which was detected on CPU 2. I nicely
got shown stack traces in the kernel log for all CPUs including CPU 0,
which was running 'PID: 111 Comm: kworker/0:1H' and was in the middle of
__mmc_switch().
I then ended up at the kdb prompt where switched over to kgdb to try to
look at local variables of the process on CPU 0. I found that I couldn't.
Digging more, I found that I had no info on any tasks running on CPUs
other than CPU 2 and that asking kdb for help showed me "Error: no saved
data for this cpu". This was because all the CPUs were offline.
Let's move the entry of kdb/kgdb to a direct call from panic() and stop
using the generic notifier. Putting a direct call in allows us to order
things more properly and it also doesn't seem like we're breaking any
abstractions by calling into the debugger from the panic function.
Daniel said:
: This patch changes the way kdump and kgdb interact with each other.
: However it would seem rather odd to have both tools simultaneously armed
: and, even if they were, the user still has the option to use panic_timeout
: to force a kdump to happen. Thus I think the change of order is
: acceptable.
Link: http://lkml.kernel.org/r/20190703170354.217312-1-dianders@chromium.org
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Feng Tang <feng.tang@intel.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 9012d01166 ("compiler: allow all arches to enable
CONFIG_OPTIMIZE_INLINING") allowed all architectures to enable this
option. A couple of build errors were reported by randconfig, but all of
them have been ironed out.
Towards the goal of removing CONFIG_OPTIMIZE_INLINING entirely (and it
will simplify the 'inline' macro in compiler_types.h), this commit changes
it to always-on option. Going forward, the compiler will always be
allowed to not inline functions marked 'inline'.
This is not a problem for x86 since it has been long used by
arch/x86/configs/{x86_64,i386}_defconfig.
I am keeping the config option just in case any problem crops up for other
architectures.
The code clean-up will be done after confirming this is solid.
Link: http://lkml.kernel.org/r/20190830034304.24259-1-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a user process exits, the kernel cleans up the mm_struct of the user
process and during cleanup, check_mm() checks the page tables of the user
process for corruption (E.g: unexpected page flags set/cleared). For
corrupted page tables, the error message printed by check_mm() isn't very
clear as it prints the loop index instead of page table type (E.g:
Resident file mapping pages vs Resident shared memory pages). The loop
index in check_mm() is used to index rss_stat[] which represents
individual memory type stats. Hence, instead of printing index, print
memory type, thereby improving error message.
Without patch:
--------------
[ 204.836425] mm/pgtable-generic.c:29: bad p4d 0000000089eb4e92(800000025f941467)
[ 204.836544] BUG: Bad rss-counter state mm:00000000f75895ea idx:0 val:2
[ 204.836615] BUG: Bad rss-counter state mm:00000000f75895ea idx:1 val:5
[ 204.836685] BUG: non-zero pgtables_bytes on freeing mm: 20480
With patch:
-----------
[ 69.815453] mm/pgtable-generic.c:29: bad p4d 0000000084653642(800000025ca37467)
[ 69.815872] BUG: Bad rss-counter state mm:00000000014a6c03 type:MM_FILEPAGES val:2
[ 69.815962] BUG: Bad rss-counter state mm:00000000014a6c03 type:MM_ANONPAGES val:5
[ 69.816050] BUG: non-zero pgtables_bytes on freeing mm: 20480
Also, change print function (from printk(KERN_ALERT, ..) to pr_alert()) so
that it matches the other print statement.
Link: http://lkml.kernel.org/r/da75b5153f617f4c5739c08ee6ebeb3d19db0fbc.1565123758.git.sai.praneeth.prakhya@intel.com
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/reiserfs/do_balan.c: In function balance_leaf_when_delete:
fs/reiserfs/do_balan.c:245:20: warning: variable ih set but not used [-Wunused-but-set-variable]
fs/reiserfs/do_balan.c: In function balance_leaf_insert_left:
fs/reiserfs/do_balan.c:301:7: warning: variable version set but not used [-Wunused-but-set-variable]
fs/reiserfs/do_balan.c: In function balance_leaf_insert_right:
fs/reiserfs/do_balan.c:649:7: warning: variable version set but not used [-Wunused-but-set-variable]
fs/reiserfs/do_balan.c: In function balance_leaf_new_nodes_insert:
fs/reiserfs/do_balan.c:953:7: warning: variable version set but not used [-Wunused-but-set-variable]
Link: http://lkml.kernel.org/r/1566379929-118398-8-git-send-email-zhengbin13@huawei.com
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Reported-by: Hulk Robot <hulkci@huawei.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes gcc '-Wunused-but-set-variable' warning:
fs/reiserfs/journal.c: In function flush_older_commits:
fs/reiserfs/journal.c:894:15: warning: variable first_trans_id set but not used [-Wunused-but-set-variable]
fs/reiserfs/journal.c: In function flush_journal_list:
fs/reiserfs/journal.c:1354:38: warning: variable last set but not used [-Wunused-but-set-variable]
fs/reiserfs/journal.c: In function do_journal_release:
fs/reiserfs/journal.c:1916:6: warning: variable flushed set but not used [-Wunused-but-set-variable]
fs/reiserfs/journal.c: In function do_journal_end:
fs/reiserfs/journal.c:3993:6: warning: variable old_start set but not used [-Wunused-but-set-variable]
Link: http://lkml.kernel.org/r/1566379929-118398-2-git-send-email-zhengbin13@huawei.com
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Reported-by: Hulk Robot <hulkci@huawei.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It can happen that a commit message refers to an invalid commit id,
because the referenced hash changed following a rebase, or simply by
mistake. Add a check in checkpatch.pl which checks that an hash
referenced by a Fixes tag, or just cited in the commit message, is a valid
commit id.
$ scripts/checkpatch.pl <<'EOF'
Subject: [PATCH] test commit
Sample test commit to test checkpatch.pl
Commit 1da177e4c3 ("Linux-2.6.12-rc2") really exists,
commit 0bba044c4c ("tree") is valid but not a commit,
while commit b4cc0b1c0cca ("unknown") is invalid.
Fixes: f0cacc14cade ("unknown")
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
EOF
WARNING: Unknown commit id '0bba044c4ce7', maybe rebased or not pulled?
#8:
commit 0bba044c4c ("tree") is valid but not a commit,
WARNING: Unknown commit id 'b4cc0b1c0cca', maybe rebased or not pulled?
#9:
while commit b4cc0b1c0cca ("unknown") is invalid.
WARNING: Unknown commit id 'f0cacc14cade', maybe rebased or not pulled?
#11:
Fixes: f0cacc14cade ("unknown")
total: 0 errors, 3 warnings, 4 lines checked
Link: http://lkml.kernel.org/r/20190711001640.13398-1-mcroce@redhat.com
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I'm seeing a bunch of debug prints from a user of print_hex_dump_bytes()
in my kernel logs, but I don't have CONFIG_DYNAMIC_DEBUG enabled nor do I
have DEBUG defined in my build. The problem is that
print_hex_dump_bytes() calls a wrapper function in lib/hexdump.c that
calls print_hex_dump() with KERN_DEBUG level. There are three cases to
consider here
1. CONFIG_DYNAMIC_DEBUG=y --> call dynamic_hex_dum()
2. CONFIG_DYNAMIC_DEBUG=n && DEBUG --> call print_hex_dump()
3. CONFIG_DYNAMIC_DEBUG=n && !DEBUG --> stub it out
Right now, that last case isn't detected and we still call
print_hex_dump() from the stub wrapper.
Let's make print_hex_dump_bytes() only call print_hex_dump_debug() so that
it works properly in all cases.
Case #1, print_hex_dump_debug() calls dynamic_hex_dump() and we get same
behavior. Case #2, print_hex_dump_debug() calls print_hex_dump() with
KERN_DEBUG and we get the same behavior. Case #3, print_hex_dump_debug()
is a nop, changing behavior to what we want, i.e. print nothing.
Link: http://lkml.kernel.org/r/20190816235624.115280-1-swboyd@chromium.org
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When building with W=1, a number of warnings are issued:
CC lib/extable.o
lib/extable.c:63:6: warning: no previous prototype for 'sort_extable' [-Wmissing-prototypes]
63 | void sort_extable(struct exception_table_entry *start,
| ^~~~~~~~~~~~
lib/extable.c:75:6: warning: no previous prototype for 'trim_init_extable' [-Wmissing-prototypes]
75 | void trim_init_extable(struct module *m)
| ^~~~~~~~~~~~~~~~~
lib/extable.c:115:1: warning: no previous prototype for 'search_extable' [-Wmissing-prototypes]
115 | search_extable(const struct exception_table_entry *base,
| ^~~~~~~~~~~~~~
Add the missing #include for the prototypes.
Link: http://lkml.kernel.org/r/45574.1565235784@turing-police
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When building with W=1, we get some warnings:
l CC lib/generic-radix-tree.o
lib/generic-radix-tree.c:39:10: warning: no previous prototype for 'genradix_root_to_depth' [-Wmissing-prototypes]
39 | unsigned genradix_root_to_depth(struct genradix_root *r)
| ^~~~~~~~~~~~~~~~~~~~~~
lib/generic-radix-tree.c:44:23: warning: no previous prototype for 'genradix_root_to_node' [-Wmissing-prototypes]
44 | struct genradix_node *genradix_root_to_node(struct genradix_root *r)
| ^~~~~~~~~~~~~~~~~~~~~
They're not used anywhere else, so make them static inline.
Link: http://lkml.kernel.org/r/46923.1565236485@turing-police
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are many of those warnings.
In file included from ./arch/powerpc/include/asm/paca.h:15,
from ./arch/powerpc/include/asm/current.h:13,
from ./include/linux/thread_info.h:21,
from ./include/asm-generic/preempt.h:5,
from ./arch/powerpc/include/generated/asm/preempt.h:1,
from ./include/linux/preempt.h:78,
from ./include/linux/spinlock.h:51,
from fs/fs-writeback.c:19:
In function 'strncpy',
inlined from 'perf_trace_writeback_page_template' at
./include/trace/events/writeback.h:56:1:
./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified
bound 32 equals destination size [-Wstringop-truncation]
return __builtin_strncpy(p, q, size);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fix it by using the new strscpy_pad() which was introduced in "lib/string:
Add strscpy_pad() function" and will always be NUL-terminated instead of
strncpy(). Also, change strlcpy() to use strscpy_pad() in this file for
consistency.
Link: http://lkml.kernel.org/r/1564075099-27750-1-git-send-email-cai@lca.pw
Fixes: 455b286468 ("writeback: Initial tracing support")
Fixes: 028c2dd184 ("writeback: Add tracing to balance_dirty_pages")
Fixes: e84d0a4f8e ("writeback: trace event writeback_queue_io")
Fixes: b48c104d22 ("writeback: trace event bdi_dirty_ratelimit")
Fixes: cc1676d917 ("writeback: Move requeueing when I_SYNC set to writeback_sb_inodes()")
Fixes: 9fb0a7da0c ("writeback: add more tracepoints")
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Tobin C. Harding <tobin@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joe Perches <joe@perches.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Nitin Gote <nitin.r.gote@intel.com>
Cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Cc: Stephen Kitt <steve@sk2.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
