linux-stable.git/arch, branch v4.4.284

s390/bpf: Fix 64-bit subtraction of the -0x80000000 constant

2021-09-22T09:41:28+00:00

commit 6e61dc9da0b7a0d91d57c2e20b5ea4fd2d4e7e53 upstream.

The JIT uses agfi for subtracting constants, but -(-0x80000000) cannot
be represented as a 32-bit signed binary integer. Fix by using algfi in
this particular case.

Reported-by: Johan Almbladh 
Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Reviewed-by: Heiko Carstens 
Signed-off-by: Ilya Leoshkevich 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Greg Kroah-Hartman

ARC: export clear_user_page() for modules

2021-09-22T09:41:27+00:00

[ Upstream commit 6b5ff0405e4190f23780362ea324b250bc495683 ]

0day bot reports a build error:
  ERROR: modpost: "clear_user_page" [drivers/media/v4l2-core/videobuf-dma-sg.ko] undefined!
so export it in arch/arc/ to fix the build error.

In most ARCHes, clear_user_page() is a macro. OTOH, in a few
ARCHes it is a function and needs to be exported.
PowerPC exported it in 2004. It looks like nds32 and nios2
still need to have it exported.

Fixes: 4102b53392d63 ("ARC: [mm] Aliasing VIPT dcache support 2/4")
Signed-off-by: Randy Dunlap 
Reported-by: kernel test robot 
Cc: Guenter Roeck 
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: Vineet Gupta 
Signed-off-by: Sasha Levin

x86/mm: Fix kern_addr_valid() to cope with existing but not present entries

2021-09-22T09:41:27+00:00

commit 34b1999da935a33be6239226bfa6cd4f704c5c88 upstream.

Jiri Olsa reported a fault when running:

  # cat /proc/kallsyms | grep ksys_read
  ffffffff8136d580 T ksys_read
  # objdump -d --start-address=0xffffffff8136d580 --stop-address=0xffffffff8136d590 /proc/kcore

  /proc/kcore:     file format elf64-x86-64

  Segmentation fault

  general protection fault, probably for non-canonical address 0xf887ffcbff000: 0000 [#1] SMP PTI
  CPU: 12 PID: 1079 Comm: objdump Not tainted 5.14.0-rc5qemu+ #508
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-4.fc34 04/01/2014
  RIP: 0010:kern_addr_valid
  Call Trace:
   read_kcore
   ? rcu_read_lock_sched_held
   ? rcu_read_lock_sched_held
   ? rcu_read_lock_sched_held
   ? trace_hardirqs_on
   ? rcu_read_lock_sched_held
   ? lock_acquire
   ? lock_acquire
   ? rcu_read_lock_sched_held
   ? lock_acquire
   ? rcu_read_lock_sched_held
   ? rcu_read_lock_sched_held
   ? rcu_read_lock_sched_held
   ? lock_release
   ? _raw_spin_unlock
   ? __handle_mm_fault
   ? rcu_read_lock_sched_held
   ? lock_acquire
   ? rcu_read_lock_sched_held
   ? lock_release
   proc_reg_read
   ? vfs_read
   vfs_read
   ksys_read
   do_syscall_64
   entry_SYSCALL_64_after_hwframe

The fault happens because kern_addr_valid() dereferences existent but not
present PMD in the high kernel mappings.

Such PMDs are created when free_kernel_image_pages() frees regions larger
than 2Mb. In this case, a part of the freed memory is mapped with PMDs and
the set_memory_np_noalias() -> ... -> __change_page_attr() sequence will
mark the PMD as not present rather than wipe it completely.

Have kern_addr_valid() check whether higher level page table entries are
present before trying to dereference them to fix this issue and to avoid
similar issues in the future.

Stable backporting note:
------------------------

Note that the stable marking is for all active stable branches because
there could be cases where pagetable entries exist but are not valid -
see 9a14aefc1d28 ("x86: cpa, fix lookup_address"), for example. So make
sure to be on the safe side here and use pXY_present() accessors rather
than pXY_none() which could #GP when accessing pages in the direct map.

Also see:

  c40a56a7818c ("x86/mm/init: Remove freed kernel image areas from alias mapping")

for more info.

Reported-by: Jiri Olsa 
Signed-off-by: Mike Rapoport 
Signed-off-by: Borislav Petkov 
Reviewed-by: David Hildenbrand 
Acked-by: Dave Hansen 
Tested-by: Jiri Olsa 
Cc: 	# 4.4+
Link: https://lkml.kernel.org/r/20210819132717.19358-1-rppt@kernel.org
Signed-off-by: Greg Kroah-Hartman

parisc: fix crash with signals and alloca

2021-09-22T09:41:26+00:00

commit 030f653078316a9cc9ca6bd1b0234dcf858be35d upstream.

I was debugging some crashes on parisc and I found out that there is a
crash possibility if a function using alloca is interrupted by a signal.
The reason for the crash is that the gcc alloca implementation leaves
garbage in the upper 32 bits of the sp register. This normally doesn't
matter (the upper bits are ignored because the PSW W-bit is clear),
however the signal delivery routine in the kernel uses full 64 bits of sp
and it fails with -EFAULT if the upper 32 bits are not zero.

I created this program that demonstrates the problem:

#include 
#include 
#include 
#include 

static __attribute__((noinline,noclone)) void aa(int *size)
{
	void * volatile p = alloca(-*size);
	while (1) ;
}

static void handler(int sig)
{
	write(1, "signal delivered\n", 17);
	_exit(0);
}

int main(void)
{
	int size = -0x100;
	signal(SIGALRM, handler);
	alarm(1);
	aa(&size);
}

If you compile it with optimizations, it will crash.
The "aa" function has this disassembly:

000106a0 :
   106a0:       08 03 02 41     copy r3,r1
   106a4:       08 1e 02 43     copy sp,r3
   106a8:       6f c1 00 80     stw,ma r1,40(sp)
   106ac:       37 dc 3f c1     ldo -20(sp),ret0
   106b0:       0c 7c 12 90     stw ret0,8(r3)
   106b4:       0f 40 10 9c     ldw 0(r26),ret0		; ret0 = 0x00000000FFFFFF00
   106b8:       97 9c 00 7e     subi 3f,ret0,ret0	; ret0 = 0xFFFFFFFF0000013F
   106bc:       d7 80 1c 1a     depwi 0,31,6,ret0	; ret0 = 0xFFFFFFFF00000100
   106c0:       0b 9e 0a 1e     add,l sp,ret0,sp	;   sp = 0xFFFFFFFFxxxxxxxx
   106c4:       e8 1f 1f f7     b,l,n 106c4 ,r0

This patch fixes the bug by truncating the "usp" variable to 32 bits.

Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman

ARM: tegra: tamonten: Fix UART pad setting

2021-09-22T09:41:25+00:00

[ Upstream commit 2270ad2f4e123336af685ecedd1618701cb4ca1e ]

This patch fixes the tristate and pullup configuration for UART 1 to 3
on the Tamonten SOM.

Signed-off-by: Andreas Obergschwandtner 
Signed-off-by: Thierry Reding 
Signed-off-by: Sasha Levin

xtensa: ISS: don't panic in rs_init

2021-09-22T09:41:25+00:00

[ Upstream commit 23411c720052ad860b3e579ee4873511e367130a ]

While alloc_tty_driver failure in rs_init would mean we have much bigger
problem, there is no reason to panic when tty_register_driver fails
there. It can fail for various reasons.

So handle the failure gracefully. Actually handle them both while at it.
This will make at least the console functional as it was enabled earlier
by console_initcall in iss_console_init. Instead of shooting down the
whole system.

We move tty_port_init() after alloc_tty_driver(), so that we don't need
to destroy the port in case the latter function fails.

Cc: Chris Zankel 
Cc: Max Filippov 
Cc: linux-xtensa@linux-xtensa.org
Acked-by: Max Filippov 
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210723074317.32690-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

s390/jump_label: print real address in a case of a jump label bug

2021-09-22T09:41:25+00:00

[ Upstream commit 5492886c14744d239e87f1b0b774b5a341e755cc ]

In case of a jump label print the real address of the piece of code
where a mismatch was detected. This is right before the system panics,
so there is nothing revealed.

Signed-off-by: Heiko Carstens 
Signed-off-by: Sasha Levin

openrisc: don't printk() unconditionally

2021-09-22T09:41:23+00:00

[ Upstream commit 946e1052cdcc7e585ee5d1e72528ca49fb295243 ]

Don't call printk() when CONFIG_PRINTK is not set.
Fixes the following build errors:

or1k-linux-ld: arch/openrisc/kernel/entry.o: in function `_external_irq_handler':
(.text+0x804): undefined reference to `printk'
(.text+0x804): relocation truncated to fit: R_OR1K_INSN_REL_26 against undefined symbol `printk'

Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Signed-off-by: Randy Dunlap 
Reported-by: kernel test robot 
Cc: Jonas Bonn 
Cc: Stefan Kristiansson 
Cc: Stafford Horne 
Cc: openrisc@lists.librecores.org
Signed-off-by: Stafford Horne 
Signed-off-by: Sasha Levin

ARM: 9105/1: atags_to_fdt: don't warn about stack size

2021-09-22T09:41:23+00:00

commit b30d0289de72c62516df03fdad8d53f552c69839 upstream.

The merge_fdt_bootargs() function by definition consumes more than 1024
bytes of stack because it has a 1024 byte command line on the stack,
meaning that we always get a warning when building this file:

arch/arm/boot/compressed/atags_to_fdt.c: In function 'merge_fdt_bootargs':
arch/arm/boot/compressed/atags_to_fdt.c:98:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]

However, as this is the decompressor and we know that it has a very shallow
call chain, and we do not actually risk overflowing the kernel stack
at runtime here.

This just shuts up the warning by disabling the warning flag for this
file.

Tested on Nexus 7 2012 builds.

Acked-by: Nicolas Pitre 
Signed-off-by: David Heidelberg 
Signed-off-by: Arnd Bergmann 
Cc: 
Signed-off-by: Russell King (Oracle) 
Signed-off-by: Greg Kroah-Hartman

xen: fix setting of max_pfn in shared_info

2021-09-22T09:41:22+00:00

commit 4b511d5bfa74b1926daefd1694205c7f1bcf677f upstream.

Xen PV guests are specifying the highest used PFN via the max_pfn
field in shared_info. This value is used by the Xen tools when saving
or migrating the guest.

Unfortunately this field is misnamed, as in reality it is specifying
the number of pages (including any memory holes) of the guest, so it
is the highest used PFN + 1. Renaming isn't possible, as this is a
public Xen hypervisor interface which needs to be kept stable.

The kernel will set the value correctly initially at boot time, but
when adding more pages (e.g. due to memory hotplug or ballooning) a
real PFN number is stored in max_pfn. This is done when expanding the
p2m array, and the PFN stored there is even possibly wrong, as it
should be the last possible PFN of the just added P2M frame, and not
one which led to the P2M expansion.

Fix that by setting shared_info->max_pfn to the last possible PFN + 1.

Fixes: 98dd166ea3a3c3 ("x86/xen/p2m: hint at the last populated P2M entry")
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross 
Reviewed-by: Jan Beulich 
Link: https://lore.kernel.org/r/20210730092622.9973-2-jgross@suse.com
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman