This kernel parameter allows to force kernel to use 4-level paging even
if hardware and kernel support 5-level paging.
The option may be useful to work around regressions related to 5-level
paging.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180518103528.59260-5-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
pgtable_l5_enabled is defined using cpu_feature_enabled() but we refer
to it as a variable. This is misleading.
Make pgtable_l5_enabled() a function.
We cannot literally define it as a function due to circular dependencies
between header files. Function-alike macros is close enough.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180518103528.59260-4-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Usually pgtable_l5_enabled is defined using cpu_feature_enabled().
cpu_feature_enabled() is not available in early boot code. We use
several different preprocessor tricks to get around it. It's messy.
Unify them all.
If cpu_feature_enabled() is not yet available, USE_EARLY_PGTABLE_L5 can
be defined before all includes. It makes pgtable_l5_enabled rely on
__pgtable_l5_enabled variable instead. This approach fits all early
users.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180518103528.59260-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Hugh noticied that we calculate the address of the trampoline page table
incorrectly in cleanup_trampoline().
TRAMPOLINE_32BIT_PGTABLE_OFFSET has to be divided by sizeof(unsigned long),
since trampoline_32bit is an 'unsigned long' pointer.
TRAMPOLINE_32BIT_PGTABLE_OFFSET is zero so the bug doesn't have a
visible effect.
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: e9d0e6330e ("x86/boot/compressed/64: Prepare new top-level page table for trampoline")
Link: http://lkml.kernel.org/r/20180518103528.59260-2-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With the following commit:
fd35c88b74 ("objtool: Support GCC 8 switch tables")
I added a "can't find switch jump table" warning, to stop covering up
silent failures if add_switch_table() can't find anything.
That warning found yet another bug in the objtool switch table detection
logic. For cases 1 and 2 (as described in the comments of
find_switch_table()), the find_symbol_containing() check doesn't adjust
the offset for RIP-relative switch jumps.
Incidentally, this bug was already fixed for case 3 with:
6f5ec2993b ("objtool: Detect RIP-relative switch table references")
However, that commit missed the fix for cases 1 and 2.
The different cases are now starting to look more and more alike. So
fix the bug by consolidating them into a single case, by checking the
original dynamic jump instruction in the case 3 loop.
This also simplifies the code and makes it more robust against future
switch table detection issues -- of which I'm sure there will be many...
Switch table detection has been the most fragile area of objtool, by
far. I long for the day when we'll have a GCC plugin for annotating
switch tables. Linus asked me to delay such a plugin due to the
flakiness of the plugin infrastructure in older versions of GCC, so this
rickety code is what we're stuck with for now. At least the code is now
a little simpler than it was.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/f400541613d45689086329432f3095119ffbc328.1526674218.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rick bisected a regression on large systems which use the x2apic cluster
mode for interrupt delivery to the commit wich reworked the cluster
management.
The problem is caused by a missing initialization of the clusterid field
in the shared cluster data structures. So all structures end up with
cluster ID 0 which only allows sharing between all CPUs which belong to
cluster 0. All other CPUs with a cluster ID > 0 cannot share the data
structure because they cannot find existing data with their cluster
ID. This causes malfunction with IPIs because IPIs are sent to the wrong
cluster and the caller waits for ever that the target CPU handles the IPI.
Add the missing initialization when a upcoming CPU is the first in a
cluster so that the later booting CPUs can find the data and share it for
proper operation.
Fixes: 023a611748 ("x86/apic/x2apic: Simplify cluster management")
Reported-by: Rick Warner <rick@microway.com>
Bisected-by: Rick Warner <rick@microway.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Rick Warner <rick@microway.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1805171418210.1947@nanos.tec.linutronix.de
cleanup_trampoline() relocates the top-level page table out of
trampoline memory. We use 'top_pgtable' as our new top-level page table.
But if the 'top_pgtable' would be referenced from C in a usual way,
the address of the table will be calculated relative to RIP.
After kernel gets relocated, the address will be in the middle of
decompression buffer and the page table may get overwritten.
This leads to a crash.
We calculate the address of other page tables relative to the relocation
address. It makes them safe. We should do the same for 'top_pgtable'.
Calculate the address of 'top_pgtable' in assembly and pass down to
cleanup_trampoline().
Move the page table to .pgtable section where the rest of page tables
are. The section is @nobits so we save 4k in kernel image.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: e9d0e6330e ("x86/boot/compressed/64: Prepare new top-level page table for trampoline")
Link: http://lkml.kernel.org/r/20180516080131.27913-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Eric and Hugh have reported instant reboot due to my recent changes in
decompression code.
The root cause is that I didn't realize that we need to adjust GOT to be
able to run C code that early.
The problem is only visible with an older toolchain. Binutils >= 2.24 is
able to eliminate GOT references by replacing them with RIP-relative
address loads:
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=80d873266dec
We need to adjust GOT two times:
- before calling paging_prepare() using the initial load address
- before calling C code from the relocated kernel
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: 194a9749c7 ("x86/boot/compressed/64: Handle 5-level paging boot if kernel is above 4G")
Link: http://lkml.kernel.org/r/20180516080131.27913-2-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Typically a switch table can be found by detecting a .rodata access
followed an indirect jump:
1969: 4a 8b 0c e5 00 00 00 mov 0x0(,%r12,8),%rcx
1970: 00
196d: R_X86_64_32S .rodata+0x438
1971: e9 00 00 00 00 jmpq 1976 <dispc_runtime_suspend+0xb6a>
1972: R_X86_64_PC32 __x86_indirect_thunk_rcx-0x4
Randy Dunlap reported a case (seen with GCC 4.8) where the .rodata
access uses RIP-relative addressing:
19bd: 48 8b 3d 00 00 00 00 mov 0x0(%rip),%rdi # 19c4 <dispc_runtime_suspend+0xbb8>
19c0: R_X86_64_PC32 .rodata+0x45c
19c4: e9 00 00 00 00 jmpq 19c9 <dispc_runtime_suspend+0xbbd>
19c5: R_X86_64_PC32 __x86_indirect_thunk_rdi-0x4
In this case the relocation addend needs to be adjusted accordingly in
order to find the location of the switch table.
The fix is for case 3 (as described in the comments), but also make the
existing case 1 & 2 checks more precise by only adjusting the addend for
R_X86_64_PC32 relocations.
This fixes the following warnings:
drivers/video/fbdev/omap2/omapfb/dss/dispc.o: warning: objtool: dispc_runtime_suspend()+0xbb8: sibling call from callable instruction with modified stack frame
drivers/video/fbdev/omap2/omapfb/dss/dispc.o: warning: objtool: dispc_runtime_resume()+0xcc5: sibling call from callable instruction with modified stack frame
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/b6098294fd67afb69af8c47c9883d7a68bf0f8ea.1526305958.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
mm_pkey_is_allocated() treats pkey 0 as unallocated. That is
inconsistent with the manpages, and also inconsistent with
mm->context.pkey_allocation_map. Stop special casing it and only
disallow values that are actually bad (< 0).
The end-user visible effect of this is that you can now use
mprotect_pkey() to set pkey=0.
This is a bit nicer than what Ram proposed[1] because it is simpler
and removes special-casing for pkey 0. On the other hand, it does
allow applications to pkey_free() pkey-0, but that's just a silly
thing to do, so we are not going to protect against it.
The scenario that could happen is similar to what happens if you free
any other pkey that is in use: it might get reallocated later and used
to protect some other data. The most likely scenario is that pkey-0
comes back from pkey_alloc(), an access-disable or write-disable bit
is set in PKRU for it, and the next stack access will SIGSEGV. It's
not horribly different from if you mprotect()'d your stack or heap to
be unreadable or unwritable, which is generally very foolish, but also
not explicitly prevented by the kernel.
1. http://lkml.kernel.org/r/1522112702-27853-1-git-send-email-linuxram@us.ibm.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>p
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Fixes: 58ab9a088d ("x86/pkeys: Check against max pkey to avoid overflows")
Link: http://lkml.kernel.org/r/20180509171358.47FD785E@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Protection key 0 is the default key for all memory and will
not normally come back from pkey_alloc(). But, you might
still want pass it to mprotect_pkey().
This check ensures that you can use pkey 0.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171356.9E40B254@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This makes it possible to to tell what 'prot' a given allocation
is supposed to have. That way, if we want to change just the
pkey, we know what 'prot' to pass to mprotect_pkey().
Also, keep a record of the most recent allocation so the tests
can easily find it.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171354.AA23E228@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We dump out the entire area of the siginfo where the si_pkey_ptr is
supposed to be. But, we do some math on the poitner, which is a u32.
We intended to do byte math, not u32 math on the pointer.
Cast it over to a u8* so it works.
Also, move this block of code to below th si_code check. It doesn't
hurt anything, but the si_pkey field is gibberish for other signal
types.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171352.9BE09819@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
I got a bug report that the following code (roughly) was
causing a SIGSEGV:
mprotect(ptr, size, PROT_EXEC);
mprotect(ptr, size, PROT_NONE);
mprotect(ptr, size, PROT_READ);
*ptr = 100;
The problem is hit when the mprotect(PROT_EXEC)
is implicitly assigned a protection key to the VMA, and made
that key ACCESS_DENY|WRITE_DENY. The PROT_NONE mprotect()
failed to remove the protection key, and the PROT_NONE->
PROT_READ left the PTE usable, but the pkey still in place
and left the memory inaccessible.
To fix this, we ensure that we always "override" the pkee
at mprotect() if the VMA does not have execute-only
permissions, but the VMA has the execute-only pkey.
We had a check for PROT_READ/WRITE, but it did not work
for PROT_NONE. This entirely removes the PROT_* checks,
which ensures that PROT_NONE now works.
Reported-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Fixes: 62b5f7d013 ("mm/core, x86/mm/pkeys: Add execute-only protection keys support")
Link: http://lkml.kernel.org/r/20180509171351.084C5A71@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In our "exhaust all pkeys" test, we make sure that there
is the expected number available. Turns out that the
test did not cover the execute-only key, but discussed
it anyway. It did *not* discuss the test-allocated
key.
Now that we have a test for the mprotect(PROT_EXEC) case,
this off-by-one issue showed itself. Correct the off-by-
one and add the explanation for the case we missed.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171350.E1656B95@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Under the covers, implement executable-only memory with
protection keys when userspace calls mprotect(PROT_EXEC).
But, we did not have a selftest for that. Now we do.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171348.9EEE4BEF@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We currently have an execute-only test, but it is for
the explicit mprotect_pkey() interface. We will soon
add a test for the implicit mprotect(PROT_EXEC)
enterface. We need this code in both tests.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171347.C64AB733@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The exec-only pkey is allocated inside the kernel and userspace
is not told what it is. So, allow PK faults to occur that have
an unknown key.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171345.7FC7DA00@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
printf() and friends are unusable in signal handlers. They deadlock.
The pkey selftest does not do any normal printing in signal handlers,
only extra debugging. So, just print the format string so we get
*some* output when debugging.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171344.C53FD2F3@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is some noisy debug code at the end of the signal handler. It was
disabled by an early, unconditional "return". However, that return also
hid a dprint_in_signal=0, which kept dprint_in_signal=1 and effectively
locked us into permanent dprint_in_signal=1 behavior.
Remove the return and the dead code, fixing dprint_in_signal.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171342.846B9B2E@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
If we use assert(), the program "crashes". That can be scary to users,
so stop doing it. Just exit with a >0 exit code instead.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171340.E63EF7DA@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
do_not_expect_pk_fault() is a helper that we call when we do not expect
a PK fault to have occurred. But, it is a function, which means that
it obscures the line numbers from pkey_assert(). It also gives no
details.
Replace it with an implementation that gives nice line numbers and
also lets callers pass in a more descriptive message about what
happened that caused the unexpected fault.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171338.55D13B64@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This exercises a nasty corner case of the x86 ISA.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/67e08b69817171da8026e0eb3af0214b06b4d74f.1525800455.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Ubuntu 18.04 started exporting pkeys details in header files, resulting
in build failures and warnings in the pkeys self-tests:
protection_keys.c:232:0: warning: "SEGV_BNDERR" redefined
protection_keys.c:387:5: error: conflicting types for ‘pkey_get’
protection_keys.c:409:5: error: conflicting types for ‘pkey_set’
...
Fix these namespace conflicts and double definitions, plus also
clean up the ABI definitions to make it all a bit more readable ...
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: dave.hansen@intel.com
Cc: linux-mm@kvack.org
Cc: linuxram@us.ibm.com
Cc: mpe@ellerman.id.au
Cc: shakeelb@google.com
Cc: shuah@kernel.org
Link: http://lkml.kernel.org/r/20180514085623.GB7094@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Clang builds with defconfig started crashing after the following
commit:
fb43d6cb91 ("x86/mm: Do not auto-massage page protections")
This was caused by introducing a new global access in __startup_64().
Code in __startup_64() can be relocated during execution, but the compiler
doesn't have to generate PC-relative relocations when accessing globals
from that function. Clang actually does not generate them, which leads
to boot-time crashes. To work around this problem, every global pointer
must be adjusted using fixup_pointer().
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: dvyukov@google.com
Cc: kirill.shutemov@linux.intel.com
Cc: linux-mm@kvack.org
Cc: md@google.com
Cc: mka@chromium.org
Fixes: fb43d6cb91 ("x86/mm: Do not auto-massage page protections")
Link: http://lkml.kernel.org/r/20180509091822.191810-1-glider@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With GCC 8, some issues were found with the objtool switch table
detection.
1) In the .rodata section, immediately after the switch table, there can
be another object which contains a pointer to the function which had
the switch statement. In this case objtool wrongly considers the
function pointer to be part of the switch table. Fix it by:
a) making sure there are no pointers to the beginning of the
function; and
b) making sure there are no gaps in the switch table.
Only the former was needed, the latter adds additional protection for
future optimizations.
2) In find_switch_table(), case 1 and case 2 are missing the check to
ensure that the .rodata switch table data is anonymous, i.e. that it
isn't already associated with an ELF symbol. Fix it by adding the
same find_symbol_containing() check which is used for case 3.
This fixes the following warnings with GCC 8:
drivers/block/virtio_blk.o: warning: objtool: virtio_queue_rq()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+72
net/ipv6/icmp.o: warning: objtool: icmpv6_rcv()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+64
drivers/usb/core/quirks.o: warning: objtool: quirks_param_set()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+48
drivers/mtd/nand/raw/nand_hynix.o: warning: objtool: hynix_nand_decode_id()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+24
drivers/mtd/nand/raw/nand_samsung.o: warning: objtool: samsung_nand_decode_id()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+32
drivers/gpu/drm/nouveau/nvkm/subdev/top/gk104.o: warning: objtool: gk104_top_oneinit()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+64
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: damian <damian.tometzki@icloud.com>
Link: http://lkml.kernel.org/r/20180510224849.xwi34d6tzheb5wgw@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
GCC 8 moves a lot of unlikely code out of line to "cold" subfunctions in
.text.unlikely. Properly detect the new subfunctions and treat them as
extensions of the original functions.
This fixes a bunch of warnings like:
kernel/cgroup/cgroup.o: warning: objtool: parse_cgroup_root_flags()+0x33: sibling call from callable instruction with modified stack frame
kernel/cgroup/cgroup.o: warning: objtool: cgroup_addrm_files()+0x290: sibling call from callable instruction with modified stack frame
kernel/cgroup/cgroup.o: warning: objtool: cgroup_apply_control_enable()+0x25b: sibling call from callable instruction with modified stack frame
kernel/cgroup/cgroup.o: warning: objtool: rebind_subsystems()+0x325: sibling call from callable instruction with modified stack frame
Reported-and-tested-by: damian <damian.tometzki@icloud.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/0965e7fcfc5f31a276f0c7f298ff770c19b68706.1525923412.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Objtool has some crude logic for detecting static "noreturn" functions
(aka "dead ends"). This is necessary for being able to correctly follow
GCC code flow when such functions are called.
It's remotely possible for two functions to call each other via sibling
calls. If they don't have RET instructions, objtool's noreturn
detection logic goes into a recursive loop:
drivers/char/ipmi/ipmi_ssif.o: warning: objtool: return_hosed_msg()+0x0: infinite recursion (objtool bug!)
drivers/char/ipmi/ipmi_ssif.o: warning: objtool: deliver_recv_msg()+0x0: infinite recursion (objtool bug!)
Instead of reporting an error in this case, consider the functions to be
non-dead-ends.
Reported-and-tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: damian <damian.tometzki@icloud.com>
Link: http://lkml.kernel.org/r/7cc156408c5781a1f62085d352ced1fe39fe2f91.1525923412.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The following commit:
ee6a7354a3: kprobes/x86: Prohibit probing on exception masking instructions
Modified <asm/insn.h>, adding the insn_masking_exception() function.
Sync the tooling version of the header to it, to fix this warning:
Warning: synced file at 'tools/objtool/arch/x86/include/asm/insn.h' differs from latest kernel version at 'arch/x86/include/asm/insn.h'
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Francis Deslauriers <francis.deslauriers@efficios.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "David S . Miller" <davem@davemloft.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since MOV SS and POP SS instructions will delay the exceptions until the
next instruction is executed, single-stepping on it by uprobes must be
prohibited.
uprobe already rejects probing on POP SS (0x1f), but allows probing on MOV
SS (0x8e and reg == 2). This checks the target instruction and if it is
MOV SS or POP SS, returns -ENOTSUPP to reject probing.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Francis Deslauriers <francis.deslauriers@efficios.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "David S . Miller" <davem@davemloft.net>
Link: https://lkml.kernel.org/r/152587072544.17316.5950935243917346341.stgit@devbox
Since MOV SS and POP SS instructions will delay the exceptions until the
next instruction is executed, single-stepping on it by kprobes must be
prohibited.
However, kprobes usually executes those instructions directly on trampoline
buffer (a.k.a. kprobe-booster), except for the kprobes which has
post_handler. Thus if kprobe user probes MOV SS with post_handler, it will
do single-stepping on the MOV SS.
This means it is safe that if it is used via ftrace or perf/bpf since those
don't use the post_handler.
Anyway, since the stack switching is a rare case, it is safer just
rejecting kprobes on such instructions.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Francis Deslauriers <francis.deslauriers@efficios.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "David S . Miller" <davem@davemloft.net>
Link: https://lkml.kernel.org/r/152587069574.17316.3311695234863248641.stgit@devbox
>From ff82bedd3e12f0d3353282054ae48c3bd8c72012 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Wed, 9 May 2018 12:12:39 +0900
Subject: [PATCH v3] x86/kexec: avoid double free_page() upon do_kexec_load() failure.
syzbot is reporting crashes after memory allocation failure inside
do_kexec_load() [1]. This is because free_transition_pgtable() is called
by both init_transition_pgtable() and machine_kexec_cleanup() when memory
allocation failed inside init_transition_pgtable().
Regarding 32bit code, machine_kexec_free_page_tables() is called by both
machine_kexec_alloc_page_tables() and machine_kexec_cleanup() when memory
allocation failed inside machine_kexec_alloc_page_tables().
Fix this by leaving the error handling to machine_kexec_cleanup()
(and optionally setting NULL after free_page()).
[1] https://syzkaller.appspot.com/bug?id=91e52396168cf2bdd572fe1e1bc0bc645c1c6b40
Fixes: f5deb79679 ("x86: kexec: Use one page table in x86_64 machine_kexec")
Fixes: 92be3d6bdf ("kexec/i386: allocate page table pages dynamically")
Reported-by: syzbot <syzbot+d96f60296ef613fe1d69@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: thomas.lendacky@amd.com
Cc: prudo@linux.vnet.ibm.com
Cc: Huang Ying <ying.huang@intel.com>
Cc: syzkaller-bugs@googlegroups.com
Cc: takahiro.akashi@linaro.org
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: akpm@linux-foundation.org
Cc: dyoung@redhat.com
Cc: kirill.shutemov@linux.intel.com
Link: https://lkml.kernel.org/r/201805091942.DGG12448.tMFVFSJFQOOLHO@I-love.SAKURA.ne.jp
No point in exposing all these functions globaly as they are strict local
to the cpu management code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-----BEGIN PGP SIGNATURE-----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=qAFz
-----END PGP SIGNATURE-----
Merge tag '4.17-rc4-SMB3-Fixes' of git://git.samba.org/sfrench/cifs-2.6
Pull cifs fixes from Steve French:
"Some small SMB3 fixes for 4.17-rc5, some for stable"
* tag '4.17-rc4-SMB3-Fixes' of git://git.samba.org/sfrench/cifs-2.6:
smb3: directory sync should not return an error
cifs: smb2ops: Fix listxattr() when there are no EAs
cifs: smbd: Enable signing with smbdirect
cifs: Allocate validate negotiation request through kmalloc
Pull thermal fixes from Zhang Rui:
- fix NULL pointer dereference on module load/probe for int3403_thermal
driver
- fix an emergency shutdown issue on exynos thermal driver
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
thermal: exynos: Propagate error value from tmu_read()
thermal: exynos: Reading temperature makes sense only when TMU is turned on
thermal: int3403_thermal: Fix NULL pointer deref on module load / probe
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=Oq/z
-----END PGP SIGNATURE-----
Merge tag 'for-linus-20180511' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
"Just a few NVMe fixes this round - one fixing a use-after-free, one
fixes the return value after controller reset, and the last one fixes
an issue where some drives will spuriously EIO. We should get these
into 4.17"
* tag 'for-linus-20180511' of git://git.kernel.dk/linux-block:
nvme: add quirk to force medium priority for SQ creation
nvme: Fix sync controller reset return
nvme: fix use-after-free in nvme_free_ns_head
Merge misc fixes from Andrew Morton:
"13 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
rbtree: include rcu.h
scripts/faddr2line: fix error when addr2line output contains discriminator
ocfs2: take inode cluster lock before moving reflinked inode from orphan dir
mm, oom: fix concurrent munlock and oom reaper unmap, v3
mm: migrate: fix double call of radix_tree_replace_slot()
proc/kcore: don't bounds check against address 0
mm: don't show nr_indirectly_reclaimable in /proc/vmstat
mm: sections are not offlined during memory hotremove
z3fold: fix reclaim lock-ups
init: fix false positives in W+X checking
lib/find_bit_benchmark.c: avoid soft lockup in test_find_first_bit()
KASAN: prohibit KASAN+STRUCTLEAK combination
MAINTAINERS: update Shuah's email address
Since commit c1adf20052 ("Introduce rb_replace_node_rcu()")
rbtree_augmented.h uses RCU related data structures but does not include
the header file. It works as long as it gets somehow included before
that and fails otherwise.
Link: http://lkml.kernel.org/r/20180504103159.19938-1-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When addr2line output contains discriminator, the current awk script
cannot parse it. This patch fixes it by extracting key words using
regex which is more reliable.
$ scripts/faddr2line vmlinux tlb_flush_mmu_free+0x26
tlb_flush_mmu_free+0x26/0x50:
tlb_flush_mmu_free at mm/memory.c:258 (discriminator 3)
scripts/faddr2line: eval: line 173: unexpected EOF while looking for matching `)'
Link: http://lkml.kernel.org/r/1525323379-25193-1-git-send-email-changbin.du@intel.com
Fixes: 6870c0165f ("scripts/faddr2line: show the code context")
Signed-off-by: Changbin Du <changbin.du@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: NeilBrown <neilb@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While reflinking an inode, we create a new inode in orphan directory,
then take EX lock on it, reflink the original inode to orphan inode and
release EX lock. Once the lock is released another node could request
it in EX mode from ocfs2_recover_orphans() which causes downconvert of
the lock, on this node, to NL mode.
Later we attempt to initialize security acl for the orphan inode and
move it to the reflink destination. However, while doing this we dont
take EX lock on the inode. This could potentially cause problems
because we could be starting transaction, accessing journal and
modifying metadata of the inode while holding NL lock and with another
node holding EX lock on the inode.
Fix this by taking orphan inode cluster lock in EX mode before
initializing security and moving orphan inode to reflink destination.
Use the __tracker variant while taking inode lock to avoid recursive
locking in the ocfs2_init_security_and_acl() call chain.
Link: http://lkml.kernel.org/r/1523475107-7639-1-git-send-email-ashish.samant@oracle.com
Signed-off-by: Ashish Samant <ashish.samant@oracle.com>
Reviewed-by: Joseph Qi <jiangqi903@gmail.com>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since exit_mmap() is done without the protection of mm->mmap_sem, it is
possible for the oom reaper to concurrently operate on an mm until
MMF_OOM_SKIP is set.
This allows munlock_vma_pages_all() to concurrently run while the oom
reaper is operating on a vma. Since munlock_vma_pages_range() depends
on clearing VM_LOCKED from vm_flags before actually doing the munlock to
determine if any other vmas are locking the same memory, the check for
VM_LOCKED in the oom reaper is racy.
This is especially noticeable on architectures such as powerpc where
clearing a huge pmd requires serialize_against_pte_lookup(). If the pmd
is zapped by the oom reaper during follow_page_mask() after the check
for pmd_none() is bypassed, this ends up deferencing a NULL ptl or a
kernel oops.
Fix this by manually freeing all possible memory from the mm before
doing the munlock and then setting MMF_OOM_SKIP. The oom reaper can not
run on the mm anymore so the munlock is safe to do in exit_mmap(). It
also matches the logic that the oom reaper currently uses for
determining when to set MMF_OOM_SKIP itself, so there's no new risk of
excessive oom killing.
This issue fixes CVE-2018-1000200.
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1804241526320.238665@chino.kir.corp.google.com
Fixes: 2129258024 ("mm: oom: let oom_reap_task and exit_mmap run concurrently")
Signed-off-by: David Rientjes <rientjes@google.com>
Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org> [4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
radix_tree_replace_slot() is called twice for head page, it's obviously
a bug. Let's fix it.
Link: http://lkml.kernel.org/r/20180423072101.GA12157@hori1.linux.bs1.fc.nec.co.jp
Fixes: e71769ae52 ("mm: enable thp migration for shmem thp")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Zi Yan <zi.yan@sent.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The existing kcore code checks for bad addresses against __va(0) with
the assumption that this is the lowest address on the system. This may
not hold true on some systems (e.g. arm64) and produce overflows and
crashes. Switch to using other functions to validate the address range.
It's currently only seen on arm64 and it's not clear if anyone wants to
use that particular combination on a stable release. So this is not
urgent for stable.
Link: http://lkml.kernel.org/r/20180501201143.15121-1-labbott@redhat.com
Signed-off-by: Laura Abbott <labbott@redhat.com>
Tested-by: Dave Anderson <anderson@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>a
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
