When a module function references a vmlinux symbol which is exported
with EXPORT_SYMBOL_FOR_MODULES(), a patch to that function needs to use
a klp reloc.
Currently, livepatch fails to load such a module:
livepatch: invalid access to vmlinux symbol 'get_task_policy' from module-specific livepatch relocation section
livepatch: failed to initialize patch 'livepatch_test' for module 'testmod' (-22)
livepatch: patch 'livepatch_test' failed for module 'testmod', refusing to load module 'testmod'
klp diff puts all klp relocs in __klp_relocs.<patched object>, so
post-link names the section .klp.rela.<patched object>.<secname>, which the
kernel rejects for vmlinux symbols.
Commit 07f14d6af9 ("objtool/klp: Fix cross-module klp relocation
section naming") changed the meaning of objname in the klp rela section
name to be where the referenced symbol is referenced rather than where
it lives. That premise only holds for symbols in a module: the relocs
get applied when the patched module gets patched, and the module
dependency guarantees the referenced module is loaded by then.
A vmlinux symbol needs the opposite. It's always resolvable, and it has
to be applied when the patch module loads, before the module loader
initializes the patch module's special sections, which may reference it.
That's why livepatch rejects vmlinux symbols in module-specific
sections.
Use "vmlinux" as the section objname when the referenced symbol lives in
vmlinux. This moves such klp relocs from .klp.rela.kvm..text to
.klp.rela.vmlinux..text.
Fixes: 07f14d6af9 ("objtool/klp: Fix cross-module klp relocation section naming")
Reported-by: Dylan Hatch <dylanbhatch@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/f8e3b9fae109903a6aafb2a33310e4afdcebf58e.1786761327.git.jpoimboe@kernel.org
Closes: https://lore.kernel.org/CADBMgpz7iWC0=t=_gE-tfvv0mTPq4kg0qQ2zgPH8DVPE6eQ9Kw@mail.gmail.com
create_fake_symbols() creates a symbol per entry for special sections.
It does so in two steps: first for the sections which have
ANNOTATE_DATA_SPECIAL annotations, then for the rest, using entsize or
the reloc count to infer the entry size. The second step skips the
sections already handled by the first one by looking for a symbol at
offset 0.
That heuristic is too fuzzy: with Clang and CONFIG_CFI, it misfires on
.kcfi_traps because Clang emits a .Ltmp* assembler-local label at the
start of the section, so no symbols are created and
clone_special_sections() extracts nothing. klp-build still reports
SUCCESS, but the livepatch module has no __kcfi_traps section and the
traps for the patched functions are lost.
Look for the actual fake symbols created by the first step instead.
Fixes: da4326573a ("objtool/klp: Fix kCFI trap handling")
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Closes: https://lore.kernel.org/r/akQNqlfFC0T5pcMa@redhat.com
Acked-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/8faaead205b219607b6fc2359ae743be824056eb.1786230311.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Building a kernel via klp-build fails to link:
`__exitcall_aes_mod_exit' referenced in section `.klp.symid' of vmlinux.o: defined in discarded section `.exitcall.exit' of vmlinux.o
`__exitcall_dax_exit' referenced in section `.klp.symid' of vmlinux.o: defined in discarded section `.exitcall.exit' of vmlinux.o
`__exitcall_hid_exit' referenced in section `.klp.symid' of vmlinux.o: defined in discarded section `.exitcall.exit' of vmlinux.o
`__exitcall_usb_serial_module_exit' referenced in section `.klp.symid' of vmlinux.o: defined in discarded section `.exitcall.exit' of vmlinux.o
module_exit() on a built-in emits a static __exitcall_$fn pointer into
.exitcall.exit, which vmlinux.lds.h discards unconditionally via
EXIT_CALL. When two built-in translation units define a module_exit()
function of the same name, the resulting local symbols collide,
symid_needed() sees a duplicate and emits a .klp.symid entry for each,
referencing symbols the linker then throws away.
Same-named module_exit() functions are not rare:
dax_exit drivers/dax/device.c, drivers/dax/fsdev.c
hid_exit drivers/hid/hid-core.c, drivers/hid/usbhid/hid-core.c
aes_mod_exit arch/arm64/crypto/aes-ce-ccm-glue.c, lib/crypto/aes.c
usb_serial_module_exit module_usb_serial_driver() expands to this fixed
name in each of its ~49 users
The last one makes the collision structural rather than accidental: any
kernel with two built-in USB serial drivers has it. This is not arch
specific either; it only requires the objects to be built in rather than
modular, which is why a monolithic config trips it while a typical
distro config does not.
Add .exitcall.exit to the discarded section list so its symbols don't get
symids.
This is the same failure mode as "objtool/klp: Fix vmlinux .klp.symid
link error for .no_trim_symbol symbols", for another unconditionally
discarded allocated section.
Fixes: 029223d301 ("objtool/klp: Add .klp.symid for sympos disambiguation")
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://patch.msgid.link/m24igzlbxf.fsf@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
EXPORT_SYMBOL_FOR_MODULES() puts a symbol in a "module:<names>"
namespace, which the module loader grants access to by matching the
importing module's name against that list.
klp_reloc_needed() only creates a klp reloc for module-owned exports; a
vmlinux export gets a normal reloc. For a vmlinux symbol exported with
EXPORT_SYMBOL_FOR_MODULES(), using a normal reloc results in a modpost
failure in klp-build:
ERROR: modpost: module livepatch-foo uses symbol mpol_shared_policy_lookup from namespace module:kvm, but does not import it.
And the modpost error is correct: even with that error removed, the
patch module would fail to load:
livepatch_foo: module uses symbol (mpol_shared_policy_lookup) from namespace module:kvm, but does not import it.
livepatch_foo: Unknown symbol mpol_shared_policy_lookup (err -22)
Treat it like an unexported symbol by using a klp reloc.
Note this only affects "module:" namespaces. Ordinary namespaced
exports continue to work with normal relocs thanks to copy_import_ns(),
which propagates the patched object's import_ns tags to the patch
module.
Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://lore.kernel.org/6a6608f4-0a05-4d75-8b7f-edddfac9c5d4@redhat.com
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/fe5a00818e06ec613344d41d5944de054fcd8832.1786138493.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
klp_reloc_needed() returns true for module exports to support
late-module patching. However, clone_reloc_klp() unconditionally
rejects symbols without a twin (i.e., new references added by the
patch), even when the symbol is a known export from Module.symvers.
Relax the check: allow new references to exported symbols by only
erroring on !twin when there is no export. The export metadata from
Module.symvers provides sufficient context to emit the klp-relocation
without a twin.
For a module export that isn't sufficient on its own though, as the
resulting klp relocation will only be resolved at patch-enable time if
the exporting module is loaded.
If the original (unpatched) module already depends on the exporting
module, the dependency is safe: the module loader ensures the dependency
is satisfied before the patched module can be loaded, so the
klp relocation target will exist.
However, if the patch introduces a reference to a module that the
original doesn't depend on, there is no such guarantee. The exporting
module could be absent or could be unloaded at any time, leading to a
relocation failure or use-after-free.
So also add a build-time check: when a new symbol reference (no twin)
targets a module export, verify that the original module already has at
least one UNDEF symbol resolving to that same exporting module. If not,
error out with a diagnostic message.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/e0d725acb4774747f0e271308b4ca33daae2d5db.1786138493.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
While cloning a reloc, klp diff calls find_export() to determine whether
the referenced symbol is exported. That decides whether the reference
needs a klp reloc, which object the klp symbol belongs to, and whether
the symbol's data needs to be copied into the patch module.
But find_export() matches purely on symbol name, so a static function or
variable which happens to share its name with an export is mistaken for
a reference to that export:
- klp_reloc_needed() creates a klp reloc pointing at the exporting
module's symbol rather than the local one. For a vmlinux export it
skips the klp reloc altogether, leaving a normal reloc which the
module loader resolves to the vmlinux symbol.
- clone_reloc() treats the symbol as external and clones it without
its data, leaving a dangling reference.
- validate_special_section_klp_reloc() attributes a static branch or
call key to the wrong module, and for a vmlinux export skips the
unsupported-key check entirely.
Exports are always global, so ignore local symbols in find_export().
Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Acked-by: Song Liu <song@kernel.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/dafc7c017d1f62e2190a20dc84a52fbfc4c70210.1786138493.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
A klp relocation section is .klp.rela.<objname>.<secname>, where objname
is the object being patched.
klp-build wrongly derives objname from where the referenced symbol
lives, not where it's referenced. For a cross-module reference like
patched can_isotp code calling can.ko's can_rx_unregister(), that gives
.klp.rela.can..text rather than .klp.rela.can_isotp..text. Unless the
patch happens to patch can.ko as well, the relocation never gets applied
and the call goes off into the weeds.
Name the intermediate section __klp_relocs.<objname> so post-link can
read the patched object's name from there.
Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://lore.kernel.org/20260720145658.1103243-2-joe.lawrence@redhat.com
Acked-by: Song Liu <song@kernel.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/ee93a08f3e55e76ffa67d04e283917ddaa893f09.1786138493.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Explicitly disallow the patching and referencing of init code/data.
Otherwise it could potentially introduce some odd edge cases depending
on whether the target object's init section has been freed yet (note
that the init code still exists in the target module when doing late
module patching).
Such edge cases include sympos calculation and the patching and/or
referencing of non-existent (init-freed) code/data. Not to mention the
inherent differences in behavior that occur when the init code is only
patched *some* of the time depending on module loading order or kernel
config.
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/516e14f84cfbffa27dc19d3dcf35097504097966.1786138493.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
An x86 alternative with an empty replacement, e.g. the second entry of
ALTERNATIVE_2("orig", "repl", ft1, "", ft2)
has a replacementlen of zero. Its replacement offset still gets a
relocation, but the label it points at is the end of the previous
replacement, which is also the beginning of the *next* alternative's
replacement. The value is meaningless; get_alt_entry() already ignores
it for that reason.
klp diff doesn't ignore it. When such an alternative belongs to a
changed function, cloning its relocations drags in the unrelated
neighboring replacement, along with everything that replacement
references. On an x86 clang/lto build an empty alternative in
meminfo_proc_show() pulled in the replacement of an alternative in
proc_kcore_init(), silently emitting a klp relocation against init text
which has long since been freed by the time the patch is applied.
Add arch_alt_ignore_new_reloc() and skip such relocations when cloning.
This has to be arch specific: on arm64 a zero-length replacement instead
identifies an alternative callback, whose replacement offset points at
the callback function and must be preserved.
Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Acked-by: Song Liu <song@kernel.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/7a885b70974795c3417f3358869e62aafd4ef783.1786138493.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
create_fake_symbols() sizes each ANNOTATE_DATA_SPECIAL entry from the
offset of the next annotation, falling back to the end of the section
for the last entry. But the last entry is detected by a zero size,
which also happens for an *empty* entry: ALTERNATIVE(oldinstr, "", ft)
still annotates its zero-length replacement, at the same offset as the
next entry's annotation.
So every empty replacement gets a fake symbol spanning the entire rest
of .altinstr_replacement. That's harmless today only because
find_symbol_containing() picks the smaller of two overlapping symbols.
Track whether a next annotation was found rather than inferring it from
the size. A zero-length fake symbol is fine: find_symbol_containing()
skips those, so the properly sized symbol at the same offset still wins.
Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Acked-by: Song Liu <song@kernel.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/913e691c5009397df832c7c9a18cd5cf71b42737.1786138493.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Testing klp-build with arm64 produced the following linker error during
the original kernel build:
`__notrim.1' referenced in section `.klp.symid' of vmlinux.o: defined in discarded section `.no_trim_symbol' of vmlinux.o
symbol_get() puts a static __notrim[] in .no_trim_symbol, which GCC
names __notrim.1, __notrim.2, etc. Two or more built-in translation
units calling symbol_get() thus produce duplicate names, resulting in
corresponding .klp.symid references which trigger the above error.
Add .no_trim_symbol to the discarded section list so its symbols don't
get symids.
Note this issue is not specific to arm64: it just needs two built-in
symbol_get() callers. arm64 trips over it easily because it has KVM
always compiled in vmlinux, whereas on x86 it's typically a module.
Fixes: 029223d301 ("objtool/klp: Add .klp.symid for sympos disambiguation")
Acked-by: Song Liu <song@kernel.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/5a3cc4cded743167dd0878220201d80f7e48e5d7.1786138493.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Sync up the kernel and tooling headers to fix this build warning:
Warning: Kernel ABI header at 'tools/include/linux/objtool_types.h' differs from latest version at 'include/linux/objtool_types.h'
Fixes: 6e5716b187 ("objtool: Replace __ASSEMBLY__ with __ASSEMBLER__ in header files")
Cc: Thomas Huth <thuth@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembly code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.
This can be very confusing when switching between userspace
and kernelspace coding, or when dealing with uapi headers that
rather should use __ASSEMBLER__ instead. So let's standardize now
on the __ASSEMBLER__ macro that is provided by the compilers.
This is a completely mechanical patch (done with a simple "sed -i"
statement).
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260619155733.58852-1-thuth@redhat.com
find_sympos() calculates a sympos used by livepatch to disambiguate
duplicately-named symbols. For function symbols, there's a hack which
counts .text.unlikely symbols before other .text symbols, matching the
linker script's section ordering.
Not only is the hack fragile, data symbols can have the same problem.
So for example, adding a reference to pwq_cache in
ep_unregister_pollwait() can trigger a corrupt sympos and a relocation
to the wrong pwq_cache symbol in the livepatch module, resulting in a
crash or undefined behavior.
Remove the existing hack in favor of a fully deterministic solution,
using the new .klp.symid table to derive the symbol-to-id mapping from
the original vmlinux.o and the id-to-address mapping from the
corresponding vmlinux, which can then be used to determine the exact
sympos associated with the original vmlinux.
Modules don't need any special treatment: the .ko has the same
section/symbol ordering as the original whole-archive symbol table.
Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Reported-by: Ben Procknow <bprockno@redhat.com>
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: live-patching@vger.kernel.org
Link: https://lore.kernel.org/20260710153042.3156788-1-joe.lawrence@redhat.com
Link: https://lore.kernel.org/20260724221730.3126529-1-joe.lawrence@redhat.com
Link: https://patch.msgid.link/919785e3bf2245db02ff6391e735d9cb139170b1.1785727106.git.jpoimboe@kernel.org
Livepatch identifies a duplicate-named symbol by its position (sympos)
among same-named kallsyms entries, which for vmlinux are counted in
ascending address order in the final linked kernel. That order can't be
reliably derived from vmlinux.o: the final link reorders sub-sections
(.text.unlikely*, .data..*, etc).
Bridge the gap with a new .klp.symid section which can be used to
correlate symbols between vmlinux.o and vmlinux so that klp-diff can
reliably determine the sympos.
The table can't survive --gc-sections: keeping it alive would keep every
duplicate-named symbol's section alive, so the reference kernel would
stop matching the one which ships. klp-build rejects
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION instead. Nothing is lost today:
x86_64 is the only HAVE_KLP_BUILD arch and doesn't select
HAVE_LD_DEAD_CODE_DATA_ELIMINATION, arm64 and s390 have never selected
it either, and on powerpc, it's still EXPERIMENTAL and disabled by every
distro kernel.
This is the build-time half of reliable vmlinux sympos computation;
"objtool klp diff" will consume the table in a subsequent commit.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: live-patching@vger.kernel.org
Link: https://patch.msgid.link/64d50f077b569f47883c015cdb7079edb068efe8.1785727106.git.jpoimboe@kernel.org
When creating a klp reloc, klp-diff keeps the original relocation but
converts the referenced symbol to an UNDEF/WEAK placeholder tombstone
symbol, which gets fully disabled later by klp post-link. The tombstone
symbol is only needed to avoid confusing objtool when it does the final
run on the patch module.
However, for references to exported symbols, modpost sees the reference
to the tombstone symbol as a real reference to an exported symbol,
resulting in a false module dependency getting created.
Further, for a reference to a tombstone symbol which is exported into a
module namespace, e.g. via EXPORT_SYMBOL_FOR_KVM_INTERNAL(), modpost
can't satisfy the dependency, resulting in a warning like the following:
module ... uses symbol kvm_flush_remote_tlbs from namespace
module:kvm-amd,kvm-intel, but does not import it.
Rename the placeholder tombstone symbols to ".klp.tombstone.<name>" so
modpost no longer recognizes them.
Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Reported-by: Ben Procknow <bprockno@redhat.com>
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: live-patching@vger.kernel.org
Link: https://lore.kernel.org/20260720145658.1103243-5-joe.lawrence@redhat.com
Link: https://patch.msgid.link/9548393f4d89ec3b498f4f69aa6ef6b9bb7150fe.1785727106.git.jpoimboe@kernel.org
Module.symvers contains build-tree object paths as module identifiers
(e.g., "arch/x86/kvm/kvm") rather than runtime module names ("kvm").
Objtool's clone_reloc_klp() uses this field directly for exported
symbols, while unexported symbols correctly go through __find_modname().
This means that exported symbol relocations may land in a .klp.rela
section named with the build path rather than the module name. That is
a crash waiting to happen: the kernel's livepatch loader silently skips
this relocation because it doesn't match the expected klp_object name.
The unresolved relocation sits in the newly activated code, crashing
when executed.
Normalize export->mod at Module.symvers read time using the same logic
as __find_modname() (refactored into a shared normalize_modname()
helper).
Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Reported-by: Ben Procknow <bprockno@redhat.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Cc: live-patching@vger.kernel.org
Link: https://patch.msgid.link/dbe1b72931bd3c31b751fd0729613d9f2226fff6.1785727106.git.jpoimboe@kernel.org
When .modinfo has no "name=" tag, __find_modname() falls back to
converting the object's build-tree path to a runtime module name by
stripping directory components, converting '-' to '_' and truncating the
file extension.
It does all that in a single pass over the entire path, so the first dot
anywhere in the path ends the name. For an object built in a directory
whose name contains a dot, e.g. "drivers/foo-1.0/bar.o", the result is a
bogus module name.
Strip the directory components up front so only the basename is scanned
for the extension separator.
Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: live-patching@vger.kernel.org
Link: https://patch.msgid.link/9017b4609553bed16674e8f924d34691cbc2b2c1.1785727106.git.jpoimboe@kernel.org
Pull RISC-V fixes from Paul Walmsley:
- Fix swiotlb initialization on systems where DRAM is located above
4GiB (such as the Tenstorrent Blackhole cards)
- Fix an out-of-bounds access in the memory hot-remove code that can
occur on Sv39 and Sv48 systems
- Avoid oopsing during boot if the SBI component of the unaligned
access performance checking code loses a race against __init function
freeing
- Avoid attempting to install the debug-enabled vDSO when it shouldn't
be built due to !CONFIG_MMU
- Avoid some sparse warnings by adding missing __iomem notations in
get_cycles{,_hi}()
- Drop an unnecessary runtime warning in the SiFive errata handler
* tag 'riscv-for-linus-7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: vdso: Only try to install vDSO when present
riscv: mm: Fix out-of-bounds page-table walk during memory hot-remove
riscv: drop __init from vec_check_unaligned_access_speed_all_cpus
riscv: mm: fix SWIOTLB initialization for systems with DRAM above 4GB
riscv/sifive: remove warning in errata
riscv: time: Add missing __iomem in get_cycles() and get_cycles_hi()
Pull s390 updates from Vasily Gorbik:
- Fix PCI MMIO write syscall falsely reporting success for mappings not
valid for MMIO when MIO is unavailable by returning -EFAULT
- Fix CPRB parameter buffer overflows in zcrypt CCA AES cipher and ECC
private key conversion by rejecting oversized key tokens
- Fix buffer overreads and length underflow in pkey and zcrypt CCA
token validation by checking length fields against actual buffer
sizes
- Fix out of bounds permission bitmap access in zcrypt EP11 admin CPRB
filtering on custom device nodes by using AP_DOMAINS as the limit
- Fix speculative permission bitmap reads in zcrypt CCA and EP11 admin
CPRB handling by sanitizing user controlled domain indexes
- Fix sensitive key material left in zcrypt CCA clear key import
buffers by scrubbing CPRB and temporary buffers after use
* tag 's390-7.2-6' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/zcrypt: Fix missing mem scrub at clear key import in cca_clr2cipherkey()
s390/zcrypt: Close speculative mem read possibility
s390/zcrypt: Fix wrong domain value verification with EP11 CPRBs
s390/zcrypt: Fix buffer over-read in cca_cipher2protkey
s390/zcrypt: Validate length for CCA ECC private key requests
s390/zcrypt: Validate length for CCA AES cipher key requests
s390/pci: Fix s390_pci_mmio_write syscall error return without MIO
Pull misc x86 fixes from Ingo Molnar:
- Fix the boot-time memcmp() asm implementation's constraints
and optimization properties (Mauricio Faria de Oliveira)
- Move the 0xd0...0xd7 AMD Zen5 model range from the Zen6
range where it mistakenly ended up (Pratik Vishwakarma)
* tag 'x86-urgent-2026-08-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/CPU/AMD: Carve out a Zen5 models range
x86/boot: Add volatile, clobbers and zero-length test in memcmp()
Pull scheduler fix from Ingo Molnar:
- Fix wakeups of deferred DL servers to be actually deferred (Gabriele
Monaco)
* tag 'sched-urgent-2026-08-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Use revised wakeup rule only for running dl_server
Pull uprobes fix from Ingo Molnar:
- Fix uretprobes race that can crash the kernel (Breno Leitao)
* tag 'perf-urgent-2026-08-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
uprobes: Fix NULL pointer dereference in hprobe_expire()
Pull vfs fixes from Christian Brauner:
"binfmt_misc:
- Don't let an 'F' entry pin its own instance.
An entry registered with 'F' opens its interpreter at registration
time and holds that file until the entry is freed, so an entry
nobody removes by hand is only closed once the binfmt_misc
superblock is shut down.
If the interpreter lives on a mount that keeps that superblock
alive the two pin each other and the file is never closed. That's
reachable by pointing the interpreter at the instance itself or by
using the instance as an overlayfs lower layer, and once the mount
namespace is gone there's nothing left to unregister through
either.
- Restore write access when removing an entry.
Registering with the MISC_FMT_OPEN_FILE flag opens the interpreter
via open_exec() which denies write access for as long as the entry
exists, but removal only did filp_close() and never restored it.
The inode's i_writecount stayed permanently negative and opening
the interpreter for writing kept failing with ETXTBSY long after
the entry was gone.
- Use exe_file_deny_write_access() for the interpreter clone so both
sides base their decision on the same mode.
- Reject a flag character as the field delimiter. create_entry() pads
the buffer with the delimiter so the field parsers terminate even
on a truncated string, but check_special_flags() consumes flag
characters instead of scanning for the delimiter.
If the delimiter is itself a flag character the padding stops
acting as a terminator and the scan keeps reading past the end of
the allocation. Such a registration was always rejected, just only
after the out of bounds read has already happened.
- Don't leak the user namespace when the mount fails.
bm_get_tree() hands its reference to get_tree_keyed() and sget_fc()
moves it into sb->s_fs_info, but generic_shutdown_super() only
calls ->put_super() from inside the if (sb->s_root) branch and
bm_fill_super() can fail before either s_root or s_op is in place.
Drop the reference in ->kill_sb() instead, which runs
unconditionally.
netfs:
- Clear PG_private_2 on a copy-to-cache append failure.
- Handle a rolling buffer allocation failure in single-object
writeback and drop the extra folio reference
netfs_write_folio_single() took before the append.
- Release the previously batched readahead folios when
rolling_buffer_load_from_ra() fails in
netfs_prepare_read_iterator()
- Fix the folio_queue ENOMEM in writeback by adding a mempool and
passing gfp flags into the rolling buffer helpers.
iomap:
- Add a separate bio_set for iomap_split_ioend(). It can split bios
that already come from iomap_ioend_bioset and deadlock once that
bioset is exhausted.
afs:
- Set call->async for an asynchronous afs_fs_fetch_data() the way
afs_fs_fetch_data64() already does.
- Subtract subreq->transferred from subreq->len in
afs_fs_fetch_data() rather than adding it.
- Fix a UAF when sending a message"
* tag 'vfs-7.2-rc6.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
iomap: add a separate bio_set for iomap_split_ioend
binfmt_misc: don't leak the user namespace when the mount fails
binfmt_misc: reject a flag character as the field delimiter
binfmt_misc: use exe_file_deny_write_access() for the interpreter clone
binfmt_misc: restore write access when removing an entry
binfmt_misc: don't let an 'F' entry pin its own instance
netfs: Fix folio_queue ENOMEM in writeback by adding a mempool
netfs: release readahead folios on iterator preparation failure
netfs: handle single writeback rolling buffer allocation failure
netfs: clear PG_private_2 on copy-to-cache append failure
afs: Fix UAF when sending a message
afs: Fix afs_fs_fetch_data() to subtract transferred from len
afs: Fix afs_fs_fetch_data() to set call->async
Pull SCSI fixes from James Bottomley"
"No core changes. The largest driver fix is the reversion of threaded
interrupt handlers in UFS and the next is the resume deadlock fix in
hisi_sas which extends into libsas"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: ufs: core: Initialize hba->rpmbs list in ufshcd
scsi: mpi3mr: Fix potential deadlock in mpi3mr_fault_uevent_emit
scsi: target: Clear cmd_cnt when initial counter enrollment fails
scsi: zfcp: Fix memory leak during adapter release by destroying gid_pn_req
scsi: ufs: core: Revert "Delegate the interrupt service routine to a threaded IRQ handler"
scsi: ufs: core: Cancel RTC work in active-active suspend
scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write
scsi: target: iblock: Fix wrong PR ops NULL check for PREEMPT/RELEASE
scsi: ufs: dt-bindings: Add missing mcq reg for qcom,sa8255p-ufshc
scsi: libsas: Fix HA resume deadlock and hisi_sas disk-wake race
scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer
scsi: libiscsi: Fix stale-data leak into the SCSI sense buffer
Pull dmaengine fixes from Vinod Koul:
- switchtec fix for register programming
- sun6i descriptor reclaim fix
- Intel idxd fixes for double free in error and setup failure
- Qualcomm bam dma command element fix
* tag 'dmaengine-fix-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine:
dmaengine: qcom: bam_dma: Fix command element mask field for BAM v1.6.0+
dmaengine: idxd: fix fdev setup failure cleanup in idxd_cdev_open()
dmaengine: idxd: fix double free of wq, engine, and group structs
dmaengine: sun6i-dma: Fix reclaim descriptors while terminating DMA
dmaengine: switchtec-dma: fix FIELD_GET misuse when programming SE threshold
Pull i2c fixes from Andi Shyti:
"A set of fixes across several host controller drivers. The largest
part addresses three issues in the i.MX driver, while the remaining
changes fix probe ordering, power management, timeout recovery and
error handling.
amd-mp2:
- unregister callback if adapter registration fails
designware:
- defer probe until child GPIO controllers are bound
imx:
- mark adapter suspended while hardware is powered down
- fix stale slave pointer and shared IRQ registration race
- stop slave timer before clearing slave pointer
iproc:
- reset controller if START_BUSY remains set after timeout
jz4780:
- cache clock rate to avoid clk_get_rate() deadlock
qcom-cci:
- rely on runtime PM helpers for system sleep
spacemit:
- request interrupt after clock initialization"
* tag 'i2c-fixes-7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux:
i2c: qcom-cci: drop custom suspend/resume and rely on runtime PM helpers
i2c: imx: Cancel hrtimer before clearing slave pointer
i2c: imx: Fix slave registration race and error handling
i2c: iproc: reset bus after timeout if START_BUSY is stuck
i2c: imx: mark I2C adapter when hardware is powered down
i2c: designware: defer probe if child GpioInt controllers are not bound
i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock
i2c: amd-mp2: Unregister callback on adapter add failure
i2c: spacemit: request IRQ after controller initialization
Pull Kbuild fixes from Nathan Chancellor:
- Fix regression with MO= when building out of tree kernel modules due
to incorrectly overwriting build tree's Makefile
- Avoid stripping .BTF sections from modules when building debug .rpm
packages
* tag 'kbuild-fixes-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
kbuild: rpm-pkg: Preserve BTF sections in kernel modules during debuginfo stripping
kbuild: Stop modifying $(objtree)/Makefile when building oot-kmods oos
Pull tracing fixes from Steven Rostedt:
- Reset dropped_count in mmio_reset_data()
When mmio_reset_data() is called, it does not reset the dropped_count
so that subsequent runs will have incorrect reporting.
- Add NULL check for mmio_trace_array in logging functions
The functions __trace_mmiotrace_rw() and __trace_mmiotrace_map() may
have the 'tr' variable passed to it as NULL. But they both
dereference it without checking if it is NULL first.
- Check return value of __register_event() in trace_module_add_events()
If __register_event() fails, the __add_event_to_tracers() call after
it will create a file for it. If the module fails to load and its
memory is freed, the file will still point to it and it will not be
removed as the registering of the event did not complete.
Only call __add_event_to_tracers() if the __register_event() was
successful.
- Fix false positive match in regex_match_full()
The regex full matching uses a strncmp() to test against the match
string and the value. It should not match if value is a prefix of the
string to match. Check to make sure the length of the strings match
before comparing.
- Fix reader page read offset for remote buffers
A page swapped in by __rb_get_reader_page_from_remote() retains its
stale read offset, causing subsequent reads to skip events or read
past valid data.
- Fix memory leak of subbuf_ids in rb_allocate_cpu_buffer()
Remote buffers allocate a subbuf_ids array. If the allocator function
fails after it is allocated, it does not free it, resulting in a
memory leak.
* tag 'trace-v7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Fix subbuf_ids memory leak in rb_allocate_cpu_buffer() error path
ring-buffer: Fix reader page read offset for remote buffers
tracing/filters: Fix false positive match in regex_match_full()
tracing: Check return value of __register_event() in trace_module_add_events()
tracing/mmiotrace: Add NULL check for mmio_trace_array in logging functions
tracing/mmiotrace: Reset dropped_count in mmio_reset_data()
Pull ntfs fixes from Namjae Jeon:
- Keep RECALL_ON_OPEN in inode flags when reloading them from
$FILE_NAME
- Check runlist reallocation sizes for negative values and overflow
- Drop stale page cache after shrinking non-resident attributes to
prevent writeback failures and data loss
* tag 'ntfs-for-7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/ntfs:
ntfs: drop stale page-cache when shrinking a non-resident attr
ntfs: harden runlist realloc size calculations
ntfs: preserve RECALL_ON_OPEN on WSL special-file reparse points
Pull smb server fixes from Steve French:
- Use memcmp() when comparing fixed-size binary ClientGUIDs, so
embedded NUL bytes are handled correctly
- Reject repeated SMB2 NEGOTIATE requests after dialect selection
This prevents preauth_info leaks, enforces the SMB2 protocol
requirements, and serializes negotiation state updates.
- Fix a use-after-free in __close_file_table_ids() by removing the
volatile file ID from the owning IDR before dropping the IDR
reference
* tag 'v7.2-rc5-smb3-server-fixes' of git://git.samba.org/ksmbd:
ksmbd: use memcmp() to compare ClientGUIDs
ksmbd: reject repeated SMB2 NEGOTIATE requests
ksmbd: fix use-after-free in __close_file_table_ids()
Pull ata fixes from Damien Le Moal:
- Fix PCI resource initialization in the sata_mv driver to keep legacy
Marvell boards functional (Rosen)
- Fix ahci_ceva driver initialization error path (Radhey)
- Fix libata header file to remove a kernel doc compilation warning
(Randy)
- Increase the timeout for the STANDBY IMMEDIATE command to avoid
suspend failures with drives that are slow to respond to this command
(Matt)
- Fixes for the handling of timed out commands in the presence of
deferred non-NCQ commands, to avoid excessive delays in executing the
error handler (me)
- Disable link power management for a couple of WD drives that have
been identified as not functioning properly when power management is
used (Niklas)
- Fix the device iteration loop when checking for link power management
support to correctly handle port multiplier setups (Niklas)
* tag 'ata-7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux:
ata: libata-sata: fix ata_scsi_lpm_supported() iteration
ata: libata-core: Disable LPM on WD Green 2.5 480GB
ata: libata-core: Disable LPM on some WD drives
scsi: libsas: terminate deferred commands on time out
ata: libata-scsi: schedule deferred atapi command
ata: libata-scsi: terminate deferred commands on time out
ata: libata-eh: Increase STANDBY IMMEDIATE timeout
ata: libata: avoid kernel-doc warnings
ata: ahci_ceva: fix error paths in ceva_ahci_platform_enable_resources()
ata: sata_mv: accept 1 or 2 resources in platform probe
In rb_allocate_cpu_buffer(), cpu_buffer->subbuf_ids is allocated using
kcalloc() when buffer->remote is non-NULL. If a subsequent page allocation
fails (e.g., ring_buffer_desc_page() returns NULL or rb_allocate_pages()
fails), execution jumps to fail_free_reader.
While __free(kfree) automatically frees the outer cpu_buffer structure
at scope exit, kfree(cpu_buffer) does not recursively free nested heap
pointers such as cpu_buffer->subbuf_ids, resulting in a memory leak.
Fix this by explicitly freeing cpu_buffer->subbuf_ids in the
fail_free_reader error unwinding path when cpu_buffer->remote is set.
Link: https://patch.msgid.link/178550740672.380917.6067449683620196150.stgit@devnote2
Fixes: 2e67fabd8b ("ring-buffer: Introduce ring-buffer remotes")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull block fixes from Jens Axboe:
- A set of fixes for s390/dasd, via Stefan
- Fix for a missing stop of the timeout timer, if a disk has never been
added
- Clear kernel owned fields on ublk setup by default
* tag 'block-7.2-20260731' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
s390/dasd: Fix undersized format-check buffer
s390/dasd: Fix potential NULL pointer dereference
s390/dasd: Fix path verification interrupted by concurrent dasd_sleep_on_immediatly
block: stop the timeout timer when releasing a never added disk
ublk: reset kernel-owned dev_info fields in ublk_ctrl_add_dev()
Pull io_uring fixes from Jens Axboe:
- Fix for a bug in how length caps are handled in multishot, and along
with it, a generic fix for avoiding these kinds of conversion issues
in the future.
- Ensure that task restrictions are always preserved across exec.
- Revert of the io_uring controlled epoll restriction, which disallowed
nested contexts. Turns out that libuv is already using it like that,
so we cannot simply remove it, sadly.
- Fix for a reference leak in the zcrx code.
* tag 'io_uring-7.2-20260731' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
io_uring: preserve task restrictions across exec
io_uring/zcrx: don't clear master_ctx from the import path
Revert "io_uring/epoll: disallow adding an epoll file to an epoll context"
io_uring/kbuf: cap buffer selection length at MAX_RW_COUNT
io_uring/net: initialize mshot_len for send
Pull drm fixes from Dave Airlie:
"Weekly pulls request. As expected there is more AMD this week since
Alex was off last week, vmwgfx looks to have been hit with the AI
stick a bit and mediatek as well. Otherwise some minor fixes across
the board, the new normal definitely seems to be a thing.
dp:
- Restrict some DP bandwidth calculations to HDMI DFP
bridge:
- Fix small leak in bridge/display-connector
mediatek:
- Check CRTC state before freeing
- mtk_hdmi: Fix DDC adapter double put in v2
- mtk_hdmi_common: take i2c adapter module reference
- mtk_dsi: Enable HS clock only at pre-enable
- ovl_adaptor: balance component registrations
amdgpu:
- VCN 5.3 fix
- UserQ fixes
- GEM close optimization
- HDMI AV mute fix
- UML build fixes
- GFXOFF residency metrics fixes
- SMU 15 fixes
- debug_vm fix
- PSP 15 fixes
- NBIO 7.11.5 fix
- pptable use after free fix
- gpu metrics fetch fix
- DC viewport fix
- DML2.1 fix
- i2c retimer spam fix
- UMD profile pstate fix
- Power metrics format cleanup
- GTT size fix on APUs
- DC context logging fix
- PM sysfs fix for APUs
- Follow on pageflip timeout fix
amdkfd:
- Various bounds checking fixes
- Mutex locking fix
i915/xe:
- Check no-DMA huge-pte cases before DMA segment test
- sink FRL rate fix
- 200ms fix for TMDS scrambler status
vmwgfx:
- Improve various size checks and limit checks
- Fix oops when submitting invalid execbuf ioctl
- Correctly lock in vmfwgx fence signaling path
- More validation of execbuf ioctl
- Fix oops in vmwgfx vkms init failure path
- Overflow handling in shader path
panthor:
- Improve firmware validation
imagination:
- Improve imagination trace points.
qaic:
- Fix QAIC transaction length check"
* tag 'drm-fixes-2026-08-01' of https://gitlab.freedesktop.org/drm/kernel: (59 commits)
drm/i915/hdmi: Poll for 200 msec for TMDS_Scrambler_Status
drm/amd/display: Exit idle optimizations before programming
drm/amd/pm: hide pp_table sysfs on APUs
accel/qaic: use sizeof(*trans_hdr) for transaction length check
drm/panthor: validate firmware interface structure sizes
drm/xe/pt: check no-DMA huge-pte cases before DMA segment test
drm/imagination: Update the trace point pvr_job_submit_fw()
drm/i915/dp: Ignore the sink's DSC max FRL rate without a PCON DSC encoder
drm/mediatek: ovl_adaptor: balance component registrations
drm/mediatek: mtk_dsi: Enable HS clock only at pre-enable
drm/dp: Read the PCON max FRL bandwidth only for HDMI DFPs
drm/amd/display: use proper context for logging
drm/amdgpu: cap GTT size to physical RAM on APUs
drm/amd/pm: use milliwatts for GPU power sensors
drm/amdgpu: restore UMD profile pstate after runtime resume
drm/amd/display: Silence link_dpms I2C retimer failures
drm/amdkfd: hold event_mutex while checkpointing CRIU events
drm/amd/display: check if dml21_add_phantom_plane() is successful
drm/amd/display: Fix divide-by-zero in calculate_mcache_setting on zero viewport
drm/amd/display: Add AV mute wait frames to dce110_set_avmute
...
Pull devicetree fixes from Rob Herring:
- Fix NULL bus dereference in of_pci_range_parser_one()
- Prevent out-of-bounds access when too many dynamic reserved memory
regions are defined
* tag 'devicetree-fixes-for-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
of/address: Fix NULL bus dereference in of_pci_range_parser_one()
of: reserved_mem: prevent OOB when too many dynamic regions are defined
Pull hyper-v fixes from Wei Liu:
- Multiple fixes for the MSHV driver (Stanislav Kinsburskii, Wei Liu,
Yi Xie, Yousef Alhouseen)
- Multiple fixes for the VMBus driver (Hardik Garg, Michael Kelley,
Sebastian Andrzej Siewior)
* tag 'hyperv-fixes-signed-20260731' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
mshv_vtl: bounds-check cpu index in vtl mmap fault handler
mshv: Publish VP to pt_vp_array before installing the file descriptor
Drivers: hv: vmbus: add VTL2 redirect connection ID
mshv: Order pt_vp_array publish against irqfd assertion path
mshv: Fix missing error code on VP allocation failure
mshv: Fix level-triggered check on uninitialized data
mshv: Fix race in mshv_irqfd_deassign
mshv: Use kfree_rcu in mshv_portid_free
mshv: Fix sleeping under spinlock in mshv_portid_alloc
mshv: Fix duplicate GSI detection for GSI 0
Drivers: hv: vmbus: Remove vmbus_irq_initialized
Drivers: hv: vmbus: Replace lockdep_hardirq_threaded() with lockdep annotation
mshv_vtl: fix fd leak in mshv_ioctl_create_vtl()
mshv_vtl: clear hypercall output before copyout
Drivers: hv: vmbus: Set DMA coherent mask for VMBus devices
mshv: fix hv_input_get_system_property struct
Pull RTLA fix from Steven Rostedt:
- Fix timerlat top actions triggering on signal
Fix a bug in RTLA's timerlat top actions feature where on-threshold
actions are triggered on any signal, regardless of whether a latency
spike had actually occurred during the measurement.
The return retval was checked for non-zero to do actions. But if a
signal came in, it returns a negative and actions were being
incorrectly triggered when they should not have been.
* tag 'trace-tools-v7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
rtla/timerlat_top: Fix on-threshold actions firing on signal
cpu is taken from pgoff & 0xffff. cpu_online() does not reject cpu >=
nr_cpu_ids, and per_cpu_ptr() can then walk off __per_cpu_offset.
Signed-off-by: Yi Xie <xieyi@kylinos.cn>
Reviewed-by: Naman Jain <namjain@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
mshv_partition_ioctl_create_vp() called anon_inode_getfd() before
publishing the new VP into partition->pt_vp_array. anon_inode_getfd()
includes fd_install(), so the fd was live in current->files before the
publish ran.
A concurrent MSHV_RUN_VP ioctl on that fd does not serialise against the
in-progress MSHV_CREATE_VP — it takes vp->vp_mutex, not the partition
mutex. Once the VP starts running and traps, mshv_intercept_isr() can look
up partition->pt_vp_array[vp_index] and observe NULL, silently dropping the
intercept message.
Split the fd creation: reserve an fd with get_unused_fd_flags(), create the
file with anon_inode_getfile(), publish the VP via smp_store_release(), and
finally call fd_install() as the userspace-visibility commit point.
Fixes: 621191d709 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs")
Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
VMBus sends CHANNELMSG_INITIATE_CONTACT through a Hyper-V message
connection ID. Older protocol versions use VMBUS_MESSAGE_CONNECTION_ID,
while protocol version 5.0 and newer normally use
VMBUS_MESSAGE_CONNECTION_ID_4.
For a VTL2 kernel using VMBus protocol 5.0 or newer, the host
may expect INITIATE_CONTACT on either the redirect connection ID or
VMBUS_MESSAGE_CONNECTION_ID_4. There is no capability indication that
identifies which ID is active, so the driver must determine it at runtime.
During VMBus negotiation, the redirect ID is tried first because it is
used by VTL2 configurations with VMBus redirection enabled. If the
redirect ID is unavailable, the host rejects it synchronously with
HV_STATUS_INVALID_CONNECTION_ID, allowing fallback to the standard ID.
Return a distinct error for an invalid Initiate Contact connection ID so
this fallback does not mask other post-message failures or
protocol-version rejections. Preserve the existing connection ID
selection for older protocol versions or when running below VTL2.
Signed-off-by: Hardik Garg <hargar@linux.microsoft.com>
Reviewed-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Naman Jain <namjain@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
mshv_partition_ioctl_create_vp() initialises a VP struct (allocations,
mutex_init, init_waitqueue_head, page mappings) and then publishes the
pointer into partition->pt_vp_array. Several ISR paths read this array
locklessly: the intercept ISR, the two scheduler ISRs, and
mshv_try_assert_irq_fast() on the irqfd fast path.
Of these, only mshv_try_assert_irq_fast() can structurally race the
publish. It runs from an eventfd waker without holding pt_mutex, and
MSHV_IRQFD does not require the target lapic_apic_id (== vp_index) to
refer to an existing VP at registration time. A user can therefore
register an irqfd targeting a yet-to-be-created VP, then trigger
mshv_try_assert_irq_fast() concurrently with MSHV_CREATE_VP for the
same index. On weakly-ordered architectures the reader can observe a
non-NULL pointer in pt_vp_array before the initialising stores to the
VP struct become visible, leading to use of partially-initialised
fields (e.g. vp_register_page).
The other ISR readers cannot reach this race: the hypervisor will not
generate intercept or scheduler messages for a VP that has never been
told to run, and the user can only call MSHV_RUN_VP on the VP fd
returned by MSHV_CREATE_VP, which by construction is returned after
the publish. Leave those readers as plain loads.
Use smp_store_release() in mshv_partition_ioctl_create_vp() to publish
the pointer, and pair it with smp_load_acquire() in
mshv_try_assert_irq_fast(). On x86 these compile to plain accesses
under TSO; on ARM64 they emit one-instruction acquire/release barriers,
acceptable on this fast path.
The destroy-side path (destroy_partition() clearing pt_vp_array[i] to
NULL after kfree(vp)) has a separate ordering and lifetime concern
that is out of scope here.
Fixes: 621191d709 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs")
Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
In mshv_partition_ioctl_create_vp(), when kzalloc for the VP struct
fails, the code jumps to the cleanup path without setting ret. At that
point ret is 0 from the preceding successful mshv_vp_stats_map() call,
so the function returns success to userspace despite having failed to
create the VP. No fd is installed and no VP is registered in pt_vp_array,
but userspace has no way to know the operation failed.
Set ret to -ENOMEM before jumping to the cleanup path.
Fixes: 621191d709 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs")
Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
In mshv_irqfd_assign(), the level-triggered validation for resample
irqfds checks irqfd_lapic_irq.lapic_control.level_triggered before
mshv_irqfd_update() has populated the field. Since the irqfd struct is
zero-allocated, level_triggered is always 0 at that point, causing the
check to always reject resample irqfds with -EINVAL. This makes
level-triggered interrupt resampling — used to avoid interrupt storms
with assigned devices — completely non-functional.
Move the check after the mshv_irqfd_update() call, which resolves the
IRQ routing entry and populates irqfd_lapic_irq with the actual trigger
mode.
Fixes: 621191d709 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs")
Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
mshv_irqfd_deactivate() and the hlist traversal of pt_irqfds_list
require pt->pt_irqfds_lock to be held, but mshv_irqfd_deassign()
omits it. This races with the EPOLLHUP path in mshv_irqfd_wakeup(),
which does take the lock before calling mshv_irqfd_deactivate().
Additionally, mshv_irqfd_deactivate() uses hlist_del() which poisons
the node pointers rather than resetting them. Since
mshv_irqfd_is_active() relies on hlist_unhashed() (checks pprev ==
NULL), a poisoned node still appears active. If a concurrent path calls
mshv_irqfd_deactivate() again on the same irqfd, the guard fails to
prevent a double hlist_del() on poisoned pointers.
Fix both issues:
- Add the missing spin_lock_irq/spin_unlock_irq around the list
traversal in mshv_irqfd_deassign(), matching mshv_irqfd_release().
- Use hlist_del_init() instead of hlist_del() so the node is properly
marked as unhashed after removal, making the is_active guard reliable.
Fixes: 621191d709 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs")
Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
