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Linux kernel
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Pull x86 fixes from Thomas Gleixner:
- Move the command line preparation and the early command line parsing
earlier so that the command line parameters which affect
early_reserve_memory(), e.g. efi=nosftreserve, are taken into
account. This was broken when the invocation of
early_reserve_memory() was moved recently.
- Use an atomic type for the SGX page accounting, which is read and
written locklessly, to plug various race conditions related to it.
* tag 'x86-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sgx: Fix free page accounting
x86/boot: Pull up cmdline preparation and early param parsing
Pull x86 perf fixes from Thomas Gleixner:
- Remove unneded PEBS disabling when taking LBR snapshots to prevent an
unchecked MSR access error.
- Fix IIO event constraints for Snowridge and Skylake server chips.
* tag 'perf-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/perf: Fix snapshot_branch_stack warning in VM
perf/x86/intel/uncore: Fix IIO event constraints for Snowridge
perf/x86/intel/uncore: Fix IIO event constraints for Skylake Server
perf/x86/intel/uncore: Fix filter_tid mask for CHA events on Skylake Server
The SGX driver maintains a single global free page counter,
sgx_nr_free_pages, that reflects the number of free pages available
across all NUMA nodes. Correspondingly, a list of free pages is
associated with each NUMA node and sgx_nr_free_pages is updated
every time a page is added or removed from any of the free page
lists. The main usage of sgx_nr_free_pages is by the reclaimer
that runs when it (sgx_nr_free_pages) goes below a watermark
to ensure that there are always some free pages available to, for
example, support efficient page faults.
With sgx_nr_free_pages accessed and modified from a few places
it is essential to ensure that these accesses are done safely but
this is not the case. sgx_nr_free_pages is read without any
protection and updated with inconsistent protection by any one
of the spin locks associated with the individual NUMA nodes.
For example:
CPU_A CPU_B
----- -----
spin_lock(&nodeA->lock); spin_lock(&nodeB->lock);
... ...
sgx_nr_free_pages--; /* NOT SAFE */ sgx_nr_free_pages--;
spin_unlock(&nodeA->lock); spin_unlock(&nodeB->lock);
Since sgx_nr_free_pages may be protected by different spin locks
while being modified from different CPUs, the following scenario
is possible:
CPU_A CPU_B
----- -----
{sgx_nr_free_pages = 100}
spin_lock(&nodeA->lock); spin_lock(&nodeB->lock);
sgx_nr_free_pages--; sgx_nr_free_pages--;
/* LOAD sgx_nr_free_pages = 100 */ /* LOAD sgx_nr_free_pages = 100 */
/* sgx_nr_free_pages-- */ /* sgx_nr_free_pages-- */
/* STORE sgx_nr_free_pages = 99 */ /* STORE sgx_nr_free_pages = 99 */
spin_unlock(&nodeA->lock); spin_unlock(&nodeB->lock);
In the above scenario, sgx_nr_free_pages is decremented from two CPUs
but instead of sgx_nr_free_pages ending with a value that is two less
than it started with, it was only decremented by one while the number
of free pages were actually reduced by two. The consequence of
sgx_nr_free_pages not being protected is that its value may not
accurately reflect the actual number of free pages on the system,
impacting the availability of free pages in support of many flows.
The problematic scenario is when the reclaimer does not run because it
believes there to be sufficient free pages while any attempt to allocate
a page fails because there are no free pages available. In the SGX driver
the reclaimer's watermark is only 32 pages so after encountering the
above example scenario 32 times a user space hang is possible when there
are no more free pages because of repeated page faults caused by no
free pages made available.
The following flow was encountered:
asm_exc_page_fault
...
sgx_vma_fault()
sgx_encl_load_page()
sgx_encl_eldu() // Encrypted page needs to be loaded from backing
// storage into newly allocated SGX memory page
sgx_alloc_epc_page() // Allocate a page of SGX memory
__sgx_alloc_epc_page() // Fails, no free SGX memory
...
if (sgx_should_reclaim(SGX_NR_LOW_PAGES)) // Wake reclaimer
wake_up(&ksgxd_waitq);
return -EBUSY; // Return -EBUSY giving reclaimer time to run
return -EBUSY;
return -EBUSY;
return VM_FAULT_NOPAGE;
The reclaimer is triggered in above flow with the following code:
static bool sgx_should_reclaim(unsigned long watermark)
{
return sgx_nr_free_pages < watermark &&
!list_empty(&sgx_active_page_list);
}
In the problematic scenario there were no free pages available yet the
value of sgx_nr_free_pages was above the watermark. The allocation of
SGX memory thus always failed because of a lack of free pages while no
free pages were made available because the reclaimer is never started
because of sgx_nr_free_pages' incorrect value. The consequence was that
user space kept encountering VM_FAULT_NOPAGE that caused the same
address to be accessed repeatedly with the same result.
Change the global free page counter to an atomic type that
ensures simultaneous updates are done safely. While doing so, move
the updating of the variable outside of the spin lock critical
section to which it does not belong.
Cc: stable@vger.kernel.org
Fixes: 901ddbb9ecf5 ("x86/sgx: Add a basic NUMA allocation scheme to sgx_alloc_epc_page()")
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lkml.kernel.org/r/a95a40743bbd3f795b465f30922dde7f1ea9e0eb.1637004094.git.reinette.chatre@intel.com
Pull more powerpc fixes from Michael Ellerman:
- Fix a bug in copying of sigset_t for 32-bit systems, which caused X
to not start.
- Fix handling of shared LSIs (rare) with the xive interrupt controller
(Power9/10).
- Fix missing TOC setup in some KVM code, which could result in oopses
depending on kernel data layout.
- Fix DMA mapping when we have persistent memory and only one DMA
window available.
- Fix further problems with STRICT_KERNEL_RWX on 8xx, exposed by a
recent fix.
- A couple of other minor fixes.
Thanks to Alexey Kardashevskiy, Aneesh Kumar K.V, Cédric Le Goater,
Christian Zigotzky, Christophe Leroy, Daniel Axtens, Finn Thain, Greg
Kurz, Masahiro Yamada, Nicholas Piggin, and Uwe Kleine-König.
* tag 'powerpc-5.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/xive: Change IRQ domain to a tree domain
powerpc/8xx: Fix pinned TLBs with CONFIG_STRICT_KERNEL_RWX
powerpc/signal32: Fix sigset_t copy
powerpc/book3e: Fix TLBCAM preset at boot
powerpc/pseries/ddw: Do not try direct mapping with persistent memory and one window
powerpc/pseries/ddw: simplify enable_ddw()
powerpc/pseries/ddw: Revert "Extend upper limit for huge DMA window for persistent memory"
powerpc/pseries: Fix numa FORM2 parsing fallback code
powerpc/pseries: rename numa_dist_table to form2_distances
powerpc: clean vdso32 and vdso64 directories
powerpc/83xx/mpc8349emitx: Drop unused variable
KVM: PPC: Book3S HV: Use GLOBAL_TOC for kvmppc_h_set_dabr/xdabr()
When running in VM intel_pmu_snapshot_branch_stack triggers WRMSR warning
like:
[ ] unchecked MSR access error: WRMSR to 0x3f1 (tried to write 0x0000000000000000) at rIP: 0xffffffff81011a5b (intel_pmu_snapshot_branch_stack+0x3b/0xd0)
This can be triggered with BPF selftests:
tools/testing/selftests/bpf/test_progs -t get_branch_snapshot
This warning is caused by __intel_pmu_pebs_disable_all() in the VM.
Since it is not necessary to disable PEBS for LBR, remove it from
intel_pmu_snapshot_branch_stack and intel_pmu_snapshot_arch_branch_stack.
Fixes: c22ac2a3d4bd ("perf: Enable branch record for software events")
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20211112054510.2667030-1-songliubraving@fb.com
Dan reports that Anjaneya Chagam can no longer use the efi=nosoftreserve
kernel command line parameter to suppress "soft reservation" behavior.
This is due to the fact that the following call-chain happens at boot:
early_reserve_memory
|-> efi_memblock_x86_reserve_range
|-> efi_fake_memmap_early
which does
if (!efi_soft_reserve_enabled())
return;
and that would have set EFI_MEM_NO_SOFT_RESERVE after having parsed
"nosoftreserve".
However, parse_early_param() gets called *after* it, leading to the boot
cmdline not being taken into account.
Therefore, carve out the command line preparation into a separate
function which does the early param parsing too. So that it all goes
together.
And then call that function before early_reserve_memory() so that the
params would have been parsed by then.
Fixes: 8aa83e6395ce ("x86/setup: Call early_reserve_memory() earlier")
Reported-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Anjaneya Chagam <anjaneya.chagam@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/e8dd8993c38702ee6dd73b3c11f158617e665607.camel@intel.com
On 32-bit:
fs/pstore/blk.c: In function ‘__best_effort_init’:
include/linux/kern_levels.h:5:18: warning: format ‘%zu’ expects argument of type ‘size_t’, but argument 3 has type ‘long unsigned int’ [-Wformat=]
5 | #define KERN_SOH "\001" /* ASCII Start Of Header */
| ^~~~~~
include/linux/kern_levels.h:14:19: note: in expansion of macro ‘KERN_SOH’
14 | #define KERN_INFO KERN_SOH "6" /* informational */
| ^~~~~~~~
include/linux/printk.h:373:9: note: in expansion of macro ‘KERN_INFO’
373 | printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
| ^~~~~~~~~
fs/pstore/blk.c:314:3: note: in expansion of macro ‘pr_info’
314 | pr_info("attached %s (%zu) (no dedicated panic_write!)\n",
| ^~~~~~~
Cc: stable@vger.kernel.org
Fixes: 7bb9557b48fcabaa ("pstore/blk: Use the normal block device I/O path")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210629103700.1935012-1-geert@linux-m68k.org
Cc: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 4f86a06e2d6e ("irqdomain: Make normal and nomap irqdomains
exclusive") introduced an IRQ_DOMAIN_FLAG_NO_MAP flag to isolate the
'nomap' domains still in use under the powerpc arch. With this new
flag, the revmap_tree of the IRQ domain is not used anymore. This
change broke the support of shared LSIs [1] in the XIVE driver because
it was relying on a lookup in the revmap_tree to query previously
mapped interrupts. Linux now creates two distinct IRQ mappings on the
same HW IRQ which can lead to unexpected behavior in the drivers.
The XIVE IRQ domain is not a direct mapping domain and its HW IRQ
interrupt number space is rather large : 1M/socket on POWER9 and
POWER10, change the XIVE driver to use a 'tree' domain type instead.
[1] For instance, a linux KVM guest with virtio-rng and virtio-balloon
devices.
Fixes: 4f86a06e2d6e ("irqdomain: Make normal and nomap irqdomains exclusive")
Cc: stable@vger.kernel.org # v5.14+
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211116134022.420412-1-clg@kaod.org
According to the latest uncore document, DATA_REQ_OF_CPU (0x83),
DATA_REQ_BY_CPU (0xc0) and COMP_BUF_OCCUPANCY (0xd5) events have
constraints. Add uncore IIO constraints for Snowridge.
Fixes: 210cc5f9db7a ("perf/x86/intel/uncore: Add uncore support for Snow Ridge server")
Signed-off-by: Alexander Antonov <alexander.antonov@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20211115090334.3789-4-alexander.antonov@linux.intel.com
Merge misc fixes from Andrew Morton:
"15 patches.
Subsystems affected by this patch series: ipc, hexagon, mm (swap,
slab-generic, kmemleak, hugetlb, kasan, damon, and highmem), and proc"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
proc/vmcore: fix clearing user buffer by properly using clear_user()
kmap_local: don't assume kmap PTEs are linear arrays in memory
mm/damon/dbgfs: fix missed use of damon_dbgfs_lock
mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation
kasan: test: silence intentional read overflow warnings
hugetlb, userfaultfd: fix reservation restore on userfaultfd error
hugetlb: fix hugetlb cgroup refcounting during mremap
mm: kmemleak: slob: respect SLAB_NOLEAKTRACE flag
hexagon: ignore vmlinux.lds
hexagon: clean up timer-regs.h
hexagon: export raw I/O routines for modules
mm: emit the "free" trace report before freeing memory in kmem_cache_free()
shm: extend forced shm destroy to support objects from several IPC nses
ipc: WARN if trying to remove ipc object which is absent
mm/swap.c:put_pages_list(): reinitialise the page list
As spotted and explained in commit c12ab8dbc492 ("powerpc/8xx: Fix
Oops with STRICT_KERNEL_RWX without DEBUG_RODATA_TEST"), the selection
of STRICT_KERNEL_RWX without selecting DEBUG_RODATA_TEST has spotted
the lack of the DIRTY bit in the pinned kernel data TLBs.
This problem should have been detected a lot earlier if things had
been working as expected. But due to an incredible level of chance or
mishap, this went undetected because of a set of bugs: In fact the
DTLBs were not pinned, because instead of setting the reserve bit
in MD_CTR, it was set in MI_CTR that is the register for ITLBs.
But then, another huge bug was there: the physical address was
reset to 0 at the boundary between RO and RW areas, leading to the
same physical space being mapped at both 0xc0000000 and 0xc8000000.
This had by miracle no consequence until now because the entry was
not really pinned so it was overwritten soon enough to go undetected.
Of course, now that we really pin the DTLBs, it must be fixed as well.
Fixes: f76c8f6d257c ("powerpc/8xx: Add function to set pinned TLBs")
Cc: stable@vger.kernel.org # v5.8+
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Depends-on: c12ab8dbc492 ("powerpc/8xx: Fix Oops with STRICT_KERNEL_RWX without DEBUG_RODATA_TEST")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a21e9a057fe2d247a535aff0d157a54eefee017a.1636963688.git.christophe.leroy@csgroup.eu
According to the latest uncore document, COMP_BUF_OCCUPANCY (0xd5) event
can be collected on 2-3 counters. Update uncore IIO event constraints for
Skylake Server.
Fixes: cd34cd97b7b4 ("perf/x86/intel/uncore: Add Skylake server uncore support")
Signed-off-by: Alexander Antonov <alexander.antonov@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20211115090334.3789-3-alexander.antonov@linux.intel.com
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