[ Upstream commit 534bd70374 ]
When using dash as /bin/sh, the CC_HAS_ASM_GOTO_TIED_OUTPUT test fails
with a syntax error which is not the one we are looking for:
<stdin>: In function ‘foo’:
<stdin>:1:29: warning: missing terminating " character
<stdin>:1:29: error: missing terminating " character
<stdin>:2:5: error: expected ‘:’ before ‘+’ token
<stdin>:2:7: warning: missing terminating " character
<stdin>:2:7: error: missing terminating " character
<stdin>:2:5: error: expected declaration or statement at end of input
Removing '\n' solves this.
Fixes: 1aa0e8b144 ("Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug")
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 1aa0e8b144 upstream.
Add a config option to guard (future) usage of asm_volatile_goto() that
includes "tied outputs", i.e. "+" constraints that specify both an input
and output parameter. clang-13 has a bug[1] that causes compilation of
such inline asm to fail, and KVM wants to use a "+m" constraint to
implement a uaccess form of CMPXCHG[2]. E.g. the test code fails with
<stdin>:1:29: error: invalid operand in inline asm: '.long (${1:l}) - .'
int foo(int *x) { asm goto (".long (%l[bar]) - .\n": "+m"(*x) ::: bar); return *x; bar: return 0; }
^
<stdin>:1:29: error: unknown token in expression
<inline asm>:1:9: note: instantiated into assembly here
.long () - .
^
2 errors generated.
on clang-13, but passes on gcc (with appropriate asm goto support). The
bug is fixed in clang-14, but won't be backported to clang-13 as the
changes are too invasive/risky.
gcc also had a similar bug[3], fixed in gcc-11, where gcc failed to
account for its behavior of assigning two numbers to tied outputs (one
for input, one for output) when evaluating symbolic references.
[1] https://github.com/ClangBuiltLinux/linux/issues/1512
[2] https://lore.kernel.org/all/YfMruK8%2F1izZ2VHS@google.com
[3] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98096
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220202004945.2540433-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2f14062bb1 upstream.
Currently, start_kernel() adds latent entropy and the command line to
the entropy bool *after* the RNG has been initialized, deferring when
it's actually used by things like stack canaries until the next time
the pool is seeded. This surely is not intended.
Rather than splitting up which entropy gets added where and when between
start_kernel() and random_init(), just do everything in random_init(),
which should eliminate these kinds of bugs in the future.
While we're at it, rename the awkwardly titled "rand_initialize()" to
the more standard "random_init()" nomenclature.
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fe222a6ca2 upstream.
Currently time_init() is called after rand_initialize(), but
rand_initialize() makes use of the timer on various platforms, and
sometimes this timer needs to be initialized by time_init() first. In
order for random_get_entropy() to not return zero during early boot when
it's potentially used as an entropy source, reverse the order of these
two calls. The block doing random initialization was right before
time_init() before, so changing the order shouldn't have any complicated
effects.
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 08389d8882 upstream.
Add a kconfig knob which allows for unprivileged bpf to be disabled by default.
If set, the knob sets /proc/sys/kernel/unprivileged_bpf_disabled to value of 2.
This still allows a transition of 2 -> {0,1} through an admin. Similarly,
this also still keeps 1 -> {1} behavior intact, so that once set to permanently
disabled, it cannot be undone aside from a reboot.
We've also added extra2 with max of 2 for the procfs handler, so that an admin
still has a chance to toggle between 0 <-> 2.
Either way, as an additional alternative, applications can make use of CAP_BPF
that we added a while ago.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/74ec548079189e4e4dffaeb42b8987bb3c852eee.1620765074.git.daniel@iogearbox.net
Cc: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit f1a0a376ca ]
As pointed out by commit
de9b8f5dcb ("sched: Fix crash trying to dequeue/enqueue the idle thread")
init_idle() can and will be invoked more than once on the same idle
task. At boot time, it is invoked for the boot CPU thread by
sched_init(). Then smp_init() creates the threads for all the secondary
CPUs and invokes init_idle() on them.
As the hotplug machinery brings the secondaries to life, it will issue
calls to idle_thread_get(), which itself invokes init_idle() yet again.
In this case it's invoked twice more per secondary: at _cpu_up(), and at
bringup_cpu().
Given smp_init() already initializes the idle tasks for all *possible*
CPUs, no further initialization should be required. Now, removing
init_idle() from idle_thread_get() exposes some interesting expectations
with regards to the idle task's preempt_count: the secondary startup always
issues a preempt_disable(), requiring some reset of the preempt count to 0
between hot-unplug and hotplug, which is currently served by
idle_thread_get() -> idle_init().
Given the idle task is supposed to have preemption disabled once and never
see it re-enabled, it seems that what we actually want is to initialize its
preempt_count to PREEMPT_DISABLED and leave it there. Do that, and remove
init_idle() from idle_thread_get().
Secondary startups were patched via coccinelle:
@begone@
@@
-preempt_disable();
...
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210512094636.2958515-1-valentin.schneider@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 0711f0d705 upstream.
During boot, kernel_init_freeable() initializes `cad_pid` to the init
task's struct pid. Later on, we may change `cad_pid` via a sysctl, and
when this happens proc_do_cad_pid() will increment the refcount on the
new pid via get_pid(), and will decrement the refcount on the old pid
via put_pid(). As we never called get_pid() when we initialized
`cad_pid`, we decrement a reference we never incremented, can therefore
free the init task's struct pid early. As there can be dangling
references to the struct pid, we can later encounter a use-after-free
(e.g. when delivering signals).
This was spotted when fuzzing v5.13-rc3 with Syzkaller, but seems to
have been around since the conversion of `cad_pid` to struct pid in
commit 9ec52099e4 ("[PATCH] replace cad_pid by a struct pid") from the
pre-KASAN stone age of v2.6.19.
Fix this by getting a reference to the init task's struct pid when we
assign it to `cad_pid`.
Full KASAN splat below.
==================================================================
BUG: KASAN: use-after-free in ns_of_pid include/linux/pid.h:153 [inline]
BUG: KASAN: use-after-free in task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509
Read of size 4 at addr ffff23794dda0004 by task syz-executor.0/273
CPU: 1 PID: 273 Comm: syz-executor.0 Not tainted 5.12.0-00001-g9aef892b2d15 #1
Hardware name: linux,dummy-virt (DT)
Call trace:
ns_of_pid include/linux/pid.h:153 [inline]
task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509
do_notify_parent+0x308/0xe60 kernel/signal.c:1950
exit_notify kernel/exit.c:682 [inline]
do_exit+0x2334/0x2bd0 kernel/exit.c:845
do_group_exit+0x108/0x2c8 kernel/exit.c:922
get_signal+0x4e4/0x2a88 kernel/signal.c:2781
do_signal arch/arm64/kernel/signal.c:882 [inline]
do_notify_resume+0x300/0x970 arch/arm64/kernel/signal.c:936
work_pending+0xc/0x2dc
Allocated by task 0:
slab_post_alloc_hook+0x50/0x5c0 mm/slab.h:516
slab_alloc_node mm/slub.c:2907 [inline]
slab_alloc mm/slub.c:2915 [inline]
kmem_cache_alloc+0x1f4/0x4c0 mm/slub.c:2920
alloc_pid+0xdc/0xc00 kernel/pid.c:180
copy_process+0x2794/0x5e18 kernel/fork.c:2129
kernel_clone+0x194/0x13c8 kernel/fork.c:2500
kernel_thread+0xd4/0x110 kernel/fork.c:2552
rest_init+0x44/0x4a0 init/main.c:687
arch_call_rest_init+0x1c/0x28
start_kernel+0x520/0x554 init/main.c:1064
0x0
Freed by task 270:
slab_free_hook mm/slub.c:1562 [inline]
slab_free_freelist_hook+0x98/0x260 mm/slub.c:1600
slab_free mm/slub.c:3161 [inline]
kmem_cache_free+0x224/0x8e0 mm/slub.c:3177
put_pid.part.4+0xe0/0x1a8 kernel/pid.c:114
put_pid+0x30/0x48 kernel/pid.c:109
proc_do_cad_pid+0x190/0x1b0 kernel/sysctl.c:1401
proc_sys_call_handler+0x338/0x4b0 fs/proc/proc_sysctl.c:591
proc_sys_write+0x34/0x48 fs/proc/proc_sysctl.c:617
call_write_iter include/linux/fs.h:1977 [inline]
new_sync_write+0x3ac/0x510 fs/read_write.c:518
vfs_write fs/read_write.c:605 [inline]
vfs_write+0x9c4/0x1018 fs/read_write.c:585
ksys_write+0x124/0x240 fs/read_write.c:658
__do_sys_write fs/read_write.c:670 [inline]
__se_sys_write fs/read_write.c:667 [inline]
__arm64_sys_write+0x78/0xb0 fs/read_write.c:667
__invoke_syscall arch/arm64/kernel/syscall.c:37 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:49 [inline]
el0_svc_common.constprop.1+0x16c/0x388 arch/arm64/kernel/syscall.c:129
do_el0_svc+0xf8/0x150 arch/arm64/kernel/syscall.c:168
el0_svc+0x28/0x38 arch/arm64/kernel/entry-common.c:416
el0_sync_handler+0x134/0x180 arch/arm64/kernel/entry-common.c:432
el0_sync+0x154/0x180 arch/arm64/kernel/entry.S:701
The buggy address belongs to the object at ffff23794dda0000
which belongs to the cache pid of size 224
The buggy address is located 4 bytes inside of
224-byte region [ffff23794dda0000, ffff23794dda00e0)
The buggy address belongs to the page:
page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4dda0
head:(____ptrval____) order:1 compound_mapcount:0
flags: 0x3fffc0000010200(slab|head)
raw: 03fffc0000010200 dead000000000100 dead000000000122 ffff23794d40d080
raw: 0000000000000000 0000000000190019 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff23794dd9ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff23794dd9ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff23794dda0000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff23794dda0080: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff23794dda0100: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
==================================================================
Link: https://lkml.kernel.org/r/20210524172230.38715-1-mark.rutland@arm.com
Fixes: 9ec52099e4 ("[PATCH] replace cad_pid by a struct pid")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 334ef6ed06 upstream.
While allmodconfig and allyesconfig build for s390 there are also
various bots running compile tests with randconfig, where PCI is
disabled. This reveals that a lot of drivers should actually depend on
HAS_IOMEM.
Adding this to each device driver would be a never ending story,
therefore just disable COMPILE_TEST for s390.
The reasoning is more or less the same as described in
commit bc083a64b6 ("init/Kconfig: make COMPILE_TEST depend on !UML").
Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7e0a922046 upstream.
On some archs, the idle task can call into cpu_suspend(). The cpu_suspend()
will disable or pause function graph tracing, as there's some paths in
bringing down the CPU that can have issues with its return address being
modified. The task_struct structure has a "tracing_graph_pause" atomic
counter, that when set to something other than zero, the function graph
tracer will not modify the return address.
The problem is that the tracing_graph_pause counter is initialized when the
function graph tracer is enabled. This can corrupt the counter for the idle
task if it is suspended in these architectures.
CPU 1 CPU 2
----- -----
do_idle()
cpu_suspend()
pause_graph_tracing()
task_struct->tracing_graph_pause++ (0 -> 1)
start_graph_tracing()
for_each_online_cpu(cpu) {
ftrace_graph_init_idle_task(cpu)
task-struct->tracing_graph_pause = 0 (1 -> 0)
unpause_graph_tracing()
task_struct->tracing_graph_pause-- (0 -> -1)
The above should have gone from 1 to zero, and enabled function graph
tracing again. But instead, it is set to -1, which keeps it disabled.
There's no reason that the field tracing_graph_pause on the task_struct can
not be initialized at boot up.
Cc: stable@vger.kernel.org
Fixes: 380c4b1411 ("tracing/function-graph-tracer: append the tracing_graph_flag")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211339
Reported-by: pierre.gondois@arm.com
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 1b04fa9900 ]
PowerPC testing encountered boot failures due to RCU Tasks not being
fully initialized until core_initcall() time. This commit therefore
initializes RCU Tasks (along with Rude RCU and RCU Tasks Trace) just
before early_initcall() time, thus allowing waiting on RCU Tasks grace
periods from early_initcall() handlers.
Link: https://lore.kernel.org/rcu/87eekfh80a.fsf@dja-thinkpad.axtens.net/
Fixes: 36dadef23f ("kprobes: Init kprobes in early_initcall")
Tested-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
There is only one function in init/initramfs.c that is in the .text
section, and it is marked __weak. When building with clang-12 and the
integrated assembler, this leads to a bug with recordmcount:
./scripts/recordmcount "init/initramfs.o"
Cannot find symbol for section 2: .text.
init/initramfs.o: failed
I'm not quite sure what exactly goes wrong, but I notice that this
function is only ever called from an __init function, and normally
inlined. Marking it __init as well is clearly correct and it leads to
recordmcount no longer complaining.
Link: https://lkml.kernel.org/r/20201204165742.3815221-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Barret Rhoden <brho@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull Kbuild fixes from Masahiro Yamada:
- Move -Wcast-align to W=3, which tends to be false-positive and there
is no tree-wide solution.
- Pass -fmacro-prefix-map to KBUILD_CPPFLAGS because it is a
preprocessor option and makes sense for .S files as well.
- Disable -gdwarf-2 for Clang's integrated assembler to avoid warnings.
- Disable --orphan-handling=warn for LLD 10.0.1 to avoid warnings.
- Fix undesirable line breaks in *.mod files.
* tag 'kbuild-fixes-v5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: avoid split lines in .mod files
kbuild: Disable CONFIG_LD_ORPHAN_WARN for ld.lld 10.0.1
kbuild: Hoist '--orphan-handling' into Kconfig
Kbuild: do not emit debug info for assembly with LLVM_IAS=1
kbuild: use -fmacro-prefix-map for .S sources
Makefile.extrawarn: move -Wcast-align to W=3
Pull bootconfig fixes from Steven Rostedt:
"Have bootconfig size and checksum be little endian
In case the bootconfig is created on one kind of endian machine, and
then read on the other kind of endian kernel, the size and checksum
will be incorrect. Instead, have both the size and checksum always be
little endian and have the tool and the kernel convert it from little
endian to or from the host endian"
* tag 'trace-v5.10-rc6-bootconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
docs: bootconfig: Add the endianness of fields
tools/bootconfig: Store size and checksum in footer as le32
bootconfig: Load size and checksum in the footer as le32
Currently, '--orphan-handling=warn' is spread out across four different
architectures in their respective Makefiles, which makes it a little
unruly to deal with in case it needs to be disabled for a specific
linker version (in this case, ld.lld 10.0.1).
To make it easier to control this, hoist this warning into Kconfig and
the main Makefile so that disabling it is simpler, as the warning will
only be enabled in a couple places (main Makefile and a couple of
compressed boot folders that blow away LDFLAGS_vmlinx) and making it
conditional is easier due to Kconfig syntax. One small additional
benefit of this is saving a call to ld-option on incremental builds
because we will have already evaluated it for CONFIG_LD_ORPHAN_WARN.
To keep the list of supported architectures the same, introduce
CONFIG_ARCH_WANT_LD_ORPHAN_WARN, which an architecture can select to
gain this automatically after all of the sections are specified and size
asserted. A special thanks to Kees Cook for the help text on this
config.
Link: https://github.com/ClangBuiltLinux/linux/issues/1187
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull printk fixes from Petr Mladek:
- do not lose trailing newline in pr_cont() calls
- two trivial fixes for a dead store and a config description
* tag 'printk-for-5.10-rc6-fixup' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk: finalize records with trailing newlines
printk: remove unneeded dead-store assignment
init/Kconfig: Fix CPU number in LOG_CPU_MAX_BUF_SHIFT description
