The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 277627b431a0a6401635c416a21b2a0f77a77347
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025071424-payroll-posh-4e3e@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 277627b431a0a6401635c416a21b2a0f77a77347 Mon Sep 17 00:00:00 2001
From: Al Viro <viro(a)zeniv.linux.org.uk>
Date: Sun, 6 Jul 2025 02:26:45 +0100
Subject: [PATCH] ksmbd: fix a mount write count leak in
ksmbd_vfs_kern_path_locked()
If the call of ksmbd_vfs_lock_parent() fails, we drop the parent_path
references and return an error. We need to drop the write access we
just got on parent_path->mnt before we drop the mount reference - callers
assume that ksmbd_vfs_kern_path_locked() returns with mount write
access grabbed if and only if it has returned 0.
Fixes: 864fb5d37163 ("ksmbd: fix possible deadlock in smb2_open")
Signed-off-by: Al Viro <viro(a)zeniv.linux.org.uk>
Acked-by: Namjae Jeon <linkinjeon(a)kernel.org>
Signed-off-by: Steve French <stfrench(a)microsoft.com>
diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c
index 0f3aad12e495..d3437f6644e3 100644
--- a/fs/smb/server/vfs.c
+++ b/fs/smb/server/vfs.c
@@ -1282,6 +1282,7 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name,
err = ksmbd_vfs_lock_parent(parent_path->dentry, path->dentry);
if (err) {
+ mnt_drop_write(parent_path->mnt);
path_put(path);
path_put(parent_path);
}
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 0c2b53997e8f5e2ec9e0fbd17ac0436466b65488
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025071408-overarch-ashes-8fbd@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 0c2b53997e8f5e2ec9e0fbd17ac0436466b65488 Mon Sep 17 00:00:00 2001
From: Stefan Metzmacher <metze(a)samba.org>
Date: Wed, 2 Jul 2025 09:18:05 +0200
Subject: [PATCH] smb: server: make use of rdma_destroy_qp()
The qp is created by rdma_create_qp() as t->cm_id->qp
and t->qp is just a shortcut.
rdma_destroy_qp() also calls ib_destroy_qp(cm_id->qp) internally,
but it is protected by a mutex, clears the cm_id and also calls
trace_cm_qp_destroy().
This should make the tracing more useful as both
rdma_create_qp() and rdma_destroy_qp() are traces and it makes
the code look more sane as functions from the same layer are used
for the specific qp object.
trace-cmd stream -e rdma_cma:cm_qp_create -e rdma_cma:cm_qp_destroy
shows this now while doing a mount and unmount from a client:
<...>-80 [002] 378.514182: cm_qp_create: cm.id=1 src=172.31.9.167:5445 dst=172.31.9.166:37113 tos=0 pd.id=0 qp_type=RC send_wr=867 recv_wr=255 qp_num=1 rc=0
<...>-6283 [001] 381.686172: cm_qp_destroy: cm.id=1 src=172.31.9.167:5445 dst=172.31.9.166:37113 tos=0 qp_num=1
Before we only saw the first line.
Cc: Namjae Jeon <linkinjeon(a)kernel.org>
Cc: Steve French <stfrench(a)microsoft.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky(a)gmail.com>
Cc: Hyunchul Lee <hyc.lee(a)gmail.com>
Cc: Tom Talpey <tom(a)talpey.com>
Cc: linux-cifs(a)vger.kernel.org
Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers")
Signed-off-by: Stefan Metzmacher <metze(a)samba.org>
Reviewed-by: Tom Talpey <tom(a)talpey.com>
Acked-by: Namjae Jeon <linkinjeon(a)kernel.org>
Signed-off-by: Steve French <stfrench(a)microsoft.com>
diff --git a/fs/smb/server/transport_rdma.c b/fs/smb/server/transport_rdma.c
index 64a428a06ace..c6cbe0d56e32 100644
--- a/fs/smb/server/transport_rdma.c
+++ b/fs/smb/server/transport_rdma.c
@@ -433,7 +433,8 @@ static void free_transport(struct smb_direct_transport *t)
if (t->qp) {
ib_drain_qp(t->qp);
ib_mr_pool_destroy(t->qp, &t->qp->rdma_mrs);
- ib_destroy_qp(t->qp);
+ t->qp = NULL;
+ rdma_destroy_qp(t->cm_id);
}
ksmbd_debug(RDMA, "drain the reassembly queue\n");
@@ -1940,8 +1941,8 @@ static int smb_direct_create_qpair(struct smb_direct_transport *t,
return 0;
err:
if (t->qp) {
- ib_destroy_qp(t->qp);
t->qp = NULL;
+ rdma_destroy_qp(t->cm_id);
}
if (t->recv_cq) {
ib_destroy_cq(t->recv_cq);
Starting with Rust 1.89.0 (expected 2025-08-07), under
`CONFIG_RUST_DEBUG_ASSERTIONS=y`, `objtool` may report:
rust/kernel.o: warning: objtool: _R..._6kernel4pageNtB5_4Page8read_raw()
falls through to next function _R..._6kernel4pageNtB5_4Page9write_raw()
(and many others) due to calls to the `noreturn` symbol:
core::panicking::panic_nounwind_fmt
Thus add the mangled one to the list so that `objtool` knows it is
actually `noreturn`.
See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions")
for more details.
Cc: stable(a)vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Cc: Josh Poimboeuf <jpoimboe(a)kernel.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Signed-off-by: Miguel Ojeda <ojeda(a)kernel.org>
---
tools/objtool/check.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f23bdda737aa..3257eefc41ed 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -224,6 +224,7 @@ static bool is_rust_noreturn(const struct symbol *func)
str_ends_with(func->name, "_4core9panicking14panic_explicit") ||
str_ends_with(func->name, "_4core9panicking14panic_nounwind") ||
str_ends_with(func->name, "_4core9panicking18panic_bounds_check") ||
+ str_ends_with(func->name, "_4core9panicking18panic_nounwind_fmt") ||
str_ends_with(func->name, "_4core9panicking19assert_failed_inner") ||
str_ends_with(func->name, "_4core9panicking30panic_null_pointer_dereference") ||
str_ends_with(func->name, "_4core9panicking36panic_misaligned_pointer_dereference") ||
--
2.50.1
Starting with Rust 1.89.0 (expected 2025-08-07), the Rust compiler fails
to build the `rusttest` target due to undefined references such as:
kernel...-cgu.0:(.text....+0x116): undefined reference to
`rust_helper_kunit_get_current_test'
Moreover, tooling like `modpost` gets confused:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpu/drm/nova/nova.o
ERROR: modpost: missing MODULE_LICENSE() in drivers/gpu/nova-core/nova_core.o
The reason behind both issues is that the Rust compiler will now [1]
treat `#[used]` as `#[used(linker)]` instead of `#[used(compiler)]`
for our targets. This means that the retain section flag (`R`,
`SHF_GNU_RETAIN`) will be used and that they will be marked as `unique`
too, with different IDs. In turn, that means we end up with undefined
references that did not get discarded in `rusttest` and that multiple
`.modinfo` sections are generated, which confuse tooling like `modpost`
because they only expect one.
Thus start using `#[used(compiler)]` to keep the previous behavior
and to be explicit about what we want. Sadly, it is an unstable feature
(`used_with_arg`) [2] -- we will talk to upstream Rust about it. The good
news is that it has been available for a long time (Rust >= 1.60) [3].
The changes should also be fine for previous Rust versions, since they
behave the same way as before [4].
Alternatively, we could use `#[no_mangle]` or `#[export_name = ...]`
since those still behave like `#[used(compiler)]`, but of course it is
not really what we want to express, and it requires other changes to
avoid symbol conflicts.
Cc: Björn Roy Baron <bjorn3_gh(a)protonmail.com>
Cc: David Wood <david(a)davidtw.co>
Cc: Wesley Wiser <wwiser(a)gmail.com>
Cc: stable(a)vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: https://github.com/rust-lang/rust/pull/140872 [1]
Link: https://github.com/rust-lang/rust/issues/93798 [2]
Link: https://github.com/rust-lang/rust/pull/91504 [3]
Link: https://godbolt.org/z/sxzWTMfzW [4]
Signed-off-by: Miguel Ojeda <ojeda(a)kernel.org>
---
rust/Makefile | 1 +
rust/kernel/firmware.rs | 2 +-
rust/kernel/kunit.rs | 2 +-
rust/kernel/lib.rs | 3 +++
rust/macros/module.rs | 10 +++++-----
scripts/Makefile.build | 3 ++-
6 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/rust/Makefile b/rust/Makefile
index 27dec7904c3a..115b63b7d1e3 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -194,6 +194,7 @@ quiet_cmd_rustdoc_test = RUSTDOC T $<
RUST_MODFILE=test.rs \
OBJTREE=$(abspath $(objtree)) \
$(RUSTDOC) --test $(rust_common_flags) \
+ -Zcrate-attr='feature(used_with_arg)' \
@$(objtree)/include/generated/rustc_cfg \
$(rustc_target_flags) $(rustdoc_test_target_flags) \
$(rustdoc_test_quiet) \
diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs
index 2494c96e105f..4fe621f35716 100644
--- a/rust/kernel/firmware.rs
+++ b/rust/kernel/firmware.rs
@@ -202,7 +202,7 @@ macro_rules! module_firmware {
};
#[link_section = ".modinfo"]
- #[used]
+ #[used(compiler)]
static __MODULE_FIRMWARE: [u8; $($builder)*::create(__MODULE_FIRMWARE_PREFIX)
.build_length()] = $($builder)*::create(__MODULE_FIRMWARE_PREFIX).build();
};
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
index 4b8cdcb21e77..b9e65905e121 100644
--- a/rust/kernel/kunit.rs
+++ b/rust/kernel/kunit.rs
@@ -302,7 +302,7 @@ macro_rules! kunit_unsafe_test_suite {
is_init: false,
};
- #[used]
+ #[used(compiler)]
#[allow(unused_unsafe)]
#[cfg_attr(not(target_os = "macos"), link_section = ".kunit_test_suites")]
static mut KUNIT_TEST_SUITE_ENTRY: *const ::kernel::bindings::kunit_suite =
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 6b4774b2b1c3..e13d6ed88fa6 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -34,6 +34,9 @@
// Expected to become stable.
#![feature(arbitrary_self_types)]
//
+// To be determined.
+#![feature(used_with_arg)]
+//
// `feature(derive_coerce_pointee)` is expected to become stable. Before Rust
// 1.84.0, it did not exist, so enable the predecessor features.
#![cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, feature(derive_coerce_pointee))]
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
index 2ddd2eeb2852..75efc6eeeafc 100644
--- a/rust/macros/module.rs
+++ b/rust/macros/module.rs
@@ -57,7 +57,7 @@ fn emit_base(&mut self, field: &str, content: &str, builtin: bool) {
{cfg}
#[doc(hidden)]
#[cfg_attr(not(target_os = \"macos\"), link_section = \".modinfo\")]
- #[used]
+ #[used(compiler)]
pub static __{module}_{counter}: [u8; {length}] = *{string};
",
cfg = if builtin {
@@ -249,7 +249,7 @@ mod __module_init {{
// key or a new section. For the moment, keep it simple.
#[cfg(MODULE)]
#[doc(hidden)]
- #[used]
+ #[used(compiler)]
static __IS_RUST_MODULE: () = ();
static mut __MOD: ::core::mem::MaybeUninit<{type_}> =
@@ -273,7 +273,7 @@ mod __module_init {{
#[cfg(MODULE)]
#[doc(hidden)]
- #[used]
+ #[used(compiler)]
#[link_section = \".init.data\"]
static __UNIQUE_ID___addressable_init_module: unsafe extern \"C\" fn() -> i32 = init_module;
@@ -293,7 +293,7 @@ mod __module_init {{
#[cfg(MODULE)]
#[doc(hidden)]
- #[used]
+ #[used(compiler)]
#[link_section = \".exit.data\"]
static __UNIQUE_ID___addressable_cleanup_module: extern \"C\" fn() = cleanup_module;
@@ -303,7 +303,7 @@ mod __module_init {{
#[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
#[doc(hidden)]
#[link_section = \"{initcall_section}\"]
- #[used]
+ #[used(compiler)]
pub static __{ident}_initcall: extern \"C\" fn() ->
::kernel::ffi::c_int = __{ident}_init;
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a6461ea411f7..ba71b27aa363 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -312,10 +312,11 @@ $(obj)/%.lst: $(obj)/%.c FORCE
# - Stable since Rust 1.82.0: `feature(asm_const)`, `feature(raw_ref_op)`.
# - Stable since Rust 1.87.0: `feature(asm_goto)`.
# - Expected to become stable: `feature(arbitrary_self_types)`.
+# - To be determined: `feature(used_with_arg)`.
#
# Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on
# the unstable features in use.
-rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,raw_ref_op
+rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,raw_ref_op,used_with_arg
# `--out-dir` is required to avoid temporaries being created by `rustc` in the
# current working directory, which may be not accessible in the out-of-tree
--
2.50.1
Now relocate_new_kernel_size is a .long value, which means 32bit, so its
high 32bit is undefined. This causes memcpy((void *)reboot_code_buffer,
relocate_new_kernel, relocate_new_kernel_size) in machine_kexec_prepare()
access out of range memories in some cases, and then end up with an ADE
exception.
So make relocate_new_kernel_size be a .quad value, which means 64bit, to
avoid such errors.
Cc: stable(a)vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn>
---
arch/loongarch/kernel/relocate_kernel.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/loongarch/kernel/relocate_kernel.S b/arch/loongarch/kernel/relocate_kernel.S
index 84e6de2fd973..8b5140ac9ea1 100644
--- a/arch/loongarch/kernel/relocate_kernel.S
+++ b/arch/loongarch/kernel/relocate_kernel.S
@@ -109,4 +109,4 @@ SYM_CODE_END(kexec_smp_wait)
relocate_new_kernel_end:
.section ".data"
-SYM_DATA(relocate_new_kernel_size, .long relocate_new_kernel_end - relocate_new_kernel)
+SYM_DATA(relocate_new_kernel_size, .quad relocate_new_kernel_end - relocate_new_kernel)
--
2.47.1
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 6ee9b3d84775944fb8c8a447961cd01274ac671c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025071348-swizzle-utter-2496@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 6ee9b3d84775944fb8c8a447961cd01274ac671c Mon Sep 17 00:00:00 2001
From: Yeoreum Yun <yeoreum.yun(a)arm.com>
Date: Thu, 3 Jul 2025 19:10:18 +0100
Subject: [PATCH] kasan: remove kasan_find_vm_area() to prevent possible
deadlock
find_vm_area() couldn't be called in atomic_context. If find_vm_area() is
called to reports vm area information, kasan can trigger deadlock like:
CPU0 CPU1
vmalloc();
alloc_vmap_area();
spin_lock(&vn->busy.lock)
spin_lock_bh(&some_lock);
<interrupt occurs>
<in softirq>
spin_lock(&some_lock);
<access invalid address>
kasan_report();
print_report();
print_address_description();
kasan_find_vm_area();
find_vm_area();
spin_lock(&vn->busy.lock) // deadlock!
To prevent possible deadlock while kasan reports, remove kasan_find_vm_area().
Link: https://lkml.kernel.org/r/20250703181018.580833-1-yeoreum.yun@arm.com
Fixes: c056a364e954 ("kasan: print virtual mapping info in reports")
Signed-off-by: Yeoreum Yun <yeoreum.yun(a)arm.com>
Reported-by: Yunseong Kim <ysk(a)kzalloc.com>
Reviewed-by: Andrey Ryabinin <ryabinin.a.a(a)gmail.com>
Cc: Alexander Potapenko <glider(a)google.com>
Cc: Andrey Konovalov <andreyknvl(a)gmail.com>
Cc: Byungchul Park <byungchul(a)sk.com>
Cc: Dmitriy Vyukov <dvyukov(a)google.com>
Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Cc: Steven Rostedt <rostedt(a)goodmis.org>
Cc: Vincenzo Frascino <vincenzo.frascino(a)arm.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 8357e1a33699..b0877035491f 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -370,36 +370,6 @@ static inline bool init_task_stack_addr(const void *addr)
sizeof(init_thread_union.stack));
}
-/*
- * This function is invoked with report_lock (a raw_spinlock) held. A
- * PREEMPT_RT kernel cannot call find_vm_area() as it will acquire a sleeping
- * rt_spinlock.
- *
- * For !RT kernel, the PROVE_RAW_LOCK_NESTING config option will print a
- * lockdep warning for this raw_spinlock -> spinlock dependency. This config
- * option is enabled by default to ensure better test coverage to expose this
- * kind of RT kernel problem. This lockdep splat, however, can be suppressed
- * by using DEFINE_WAIT_OVERRIDE_MAP() if it serves a useful purpose and the
- * invalid PREEMPT_RT case has been taken care of.
- */
-static inline struct vm_struct *kasan_find_vm_area(void *addr)
-{
- static DEFINE_WAIT_OVERRIDE_MAP(vmalloc_map, LD_WAIT_SLEEP);
- struct vm_struct *va;
-
- if (IS_ENABLED(CONFIG_PREEMPT_RT))
- return NULL;
-
- /*
- * Suppress lockdep warning and fetch vmalloc area of the
- * offending address.
- */
- lock_map_acquire_try(&vmalloc_map);
- va = find_vm_area(addr);
- lock_map_release(&vmalloc_map);
- return va;
-}
-
static void print_address_description(void *addr, u8 tag,
struct kasan_report_info *info)
{
@@ -429,19 +399,8 @@ static void print_address_description(void *addr, u8 tag,
}
if (is_vmalloc_addr(addr)) {
- struct vm_struct *va = kasan_find_vm_area(addr);
-
- if (va) {
- pr_err("The buggy address belongs to the virtual mapping at\n"
- " [%px, %px) created by:\n"
- " %pS\n",
- va->addr, va->addr + va->size, va->caller);
- pr_err("\n");
-
- page = vmalloc_to_page(addr);
- } else {
- pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr);
- }
+ pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr);
+ page = vmalloc_to_page(addr);
}
if (page) {
The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 6ee9b3d84775944fb8c8a447961cd01274ac671c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025071347-pregnant-dismount-40e9@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 6ee9b3d84775944fb8c8a447961cd01274ac671c Mon Sep 17 00:00:00 2001
From: Yeoreum Yun <yeoreum.yun(a)arm.com>
Date: Thu, 3 Jul 2025 19:10:18 +0100
Subject: [PATCH] kasan: remove kasan_find_vm_area() to prevent possible
deadlock
find_vm_area() couldn't be called in atomic_context. If find_vm_area() is
called to reports vm area information, kasan can trigger deadlock like:
CPU0 CPU1
vmalloc();
alloc_vmap_area();
spin_lock(&vn->busy.lock)
spin_lock_bh(&some_lock);
<interrupt occurs>
<in softirq>
spin_lock(&some_lock);
<access invalid address>
kasan_report();
print_report();
print_address_description();
kasan_find_vm_area();
find_vm_area();
spin_lock(&vn->busy.lock) // deadlock!
To prevent possible deadlock while kasan reports, remove kasan_find_vm_area().
Link: https://lkml.kernel.org/r/20250703181018.580833-1-yeoreum.yun@arm.com
Fixes: c056a364e954 ("kasan: print virtual mapping info in reports")
Signed-off-by: Yeoreum Yun <yeoreum.yun(a)arm.com>
Reported-by: Yunseong Kim <ysk(a)kzalloc.com>
Reviewed-by: Andrey Ryabinin <ryabinin.a.a(a)gmail.com>
Cc: Alexander Potapenko <glider(a)google.com>
Cc: Andrey Konovalov <andreyknvl(a)gmail.com>
Cc: Byungchul Park <byungchul(a)sk.com>
Cc: Dmitriy Vyukov <dvyukov(a)google.com>
Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Cc: Steven Rostedt <rostedt(a)goodmis.org>
Cc: Vincenzo Frascino <vincenzo.frascino(a)arm.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 8357e1a33699..b0877035491f 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -370,36 +370,6 @@ static inline bool init_task_stack_addr(const void *addr)
sizeof(init_thread_union.stack));
}
-/*
- * This function is invoked with report_lock (a raw_spinlock) held. A
- * PREEMPT_RT kernel cannot call find_vm_area() as it will acquire a sleeping
- * rt_spinlock.
- *
- * For !RT kernel, the PROVE_RAW_LOCK_NESTING config option will print a
- * lockdep warning for this raw_spinlock -> spinlock dependency. This config
- * option is enabled by default to ensure better test coverage to expose this
- * kind of RT kernel problem. This lockdep splat, however, can be suppressed
- * by using DEFINE_WAIT_OVERRIDE_MAP() if it serves a useful purpose and the
- * invalid PREEMPT_RT case has been taken care of.
- */
-static inline struct vm_struct *kasan_find_vm_area(void *addr)
-{
- static DEFINE_WAIT_OVERRIDE_MAP(vmalloc_map, LD_WAIT_SLEEP);
- struct vm_struct *va;
-
- if (IS_ENABLED(CONFIG_PREEMPT_RT))
- return NULL;
-
- /*
- * Suppress lockdep warning and fetch vmalloc area of the
- * offending address.
- */
- lock_map_acquire_try(&vmalloc_map);
- va = find_vm_area(addr);
- lock_map_release(&vmalloc_map);
- return va;
-}
-
static void print_address_description(void *addr, u8 tag,
struct kasan_report_info *info)
{
@@ -429,19 +399,8 @@ static void print_address_description(void *addr, u8 tag,
}
if (is_vmalloc_addr(addr)) {
- struct vm_struct *va = kasan_find_vm_area(addr);
-
- if (va) {
- pr_err("The buggy address belongs to the virtual mapping at\n"
- " [%px, %px) created by:\n"
- " %pS\n",
- va->addr, va->addr + va->size, va->caller);
- pr_err("\n");
-
- page = vmalloc_to_page(addr);
- } else {
- pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr);
- }
+ pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr);
+ page = vmalloc_to_page(addr);
}
if (page) {
The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 6ee9b3d84775944fb8c8a447961cd01274ac671c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025071347-compel-crate-aeba@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 6ee9b3d84775944fb8c8a447961cd01274ac671c Mon Sep 17 00:00:00 2001
From: Yeoreum Yun <yeoreum.yun(a)arm.com>
Date: Thu, 3 Jul 2025 19:10:18 +0100
Subject: [PATCH] kasan: remove kasan_find_vm_area() to prevent possible
deadlock
find_vm_area() couldn't be called in atomic_context. If find_vm_area() is
called to reports vm area information, kasan can trigger deadlock like:
CPU0 CPU1
vmalloc();
alloc_vmap_area();
spin_lock(&vn->busy.lock)
spin_lock_bh(&some_lock);
<interrupt occurs>
<in softirq>
spin_lock(&some_lock);
<access invalid address>
kasan_report();
print_report();
print_address_description();
kasan_find_vm_area();
find_vm_area();
spin_lock(&vn->busy.lock) // deadlock!
To prevent possible deadlock while kasan reports, remove kasan_find_vm_area().
Link: https://lkml.kernel.org/r/20250703181018.580833-1-yeoreum.yun@arm.com
Fixes: c056a364e954 ("kasan: print virtual mapping info in reports")
Signed-off-by: Yeoreum Yun <yeoreum.yun(a)arm.com>
Reported-by: Yunseong Kim <ysk(a)kzalloc.com>
Reviewed-by: Andrey Ryabinin <ryabinin.a.a(a)gmail.com>
Cc: Alexander Potapenko <glider(a)google.com>
Cc: Andrey Konovalov <andreyknvl(a)gmail.com>
Cc: Byungchul Park <byungchul(a)sk.com>
Cc: Dmitriy Vyukov <dvyukov(a)google.com>
Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Cc: Steven Rostedt <rostedt(a)goodmis.org>
Cc: Vincenzo Frascino <vincenzo.frascino(a)arm.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 8357e1a33699..b0877035491f 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -370,36 +370,6 @@ static inline bool init_task_stack_addr(const void *addr)
sizeof(init_thread_union.stack));
}
-/*
- * This function is invoked with report_lock (a raw_spinlock) held. A
- * PREEMPT_RT kernel cannot call find_vm_area() as it will acquire a sleeping
- * rt_spinlock.
- *
- * For !RT kernel, the PROVE_RAW_LOCK_NESTING config option will print a
- * lockdep warning for this raw_spinlock -> spinlock dependency. This config
- * option is enabled by default to ensure better test coverage to expose this
- * kind of RT kernel problem. This lockdep splat, however, can be suppressed
- * by using DEFINE_WAIT_OVERRIDE_MAP() if it serves a useful purpose and the
- * invalid PREEMPT_RT case has been taken care of.
- */
-static inline struct vm_struct *kasan_find_vm_area(void *addr)
-{
- static DEFINE_WAIT_OVERRIDE_MAP(vmalloc_map, LD_WAIT_SLEEP);
- struct vm_struct *va;
-
- if (IS_ENABLED(CONFIG_PREEMPT_RT))
- return NULL;
-
- /*
- * Suppress lockdep warning and fetch vmalloc area of the
- * offending address.
- */
- lock_map_acquire_try(&vmalloc_map);
- va = find_vm_area(addr);
- lock_map_release(&vmalloc_map);
- return va;
-}
-
static void print_address_description(void *addr, u8 tag,
struct kasan_report_info *info)
{
@@ -429,19 +399,8 @@ static void print_address_description(void *addr, u8 tag,
}
if (is_vmalloc_addr(addr)) {
- struct vm_struct *va = kasan_find_vm_area(addr);
-
- if (va) {
- pr_err("The buggy address belongs to the virtual mapping at\n"
- " [%px, %px) created by:\n"
- " %pS\n",
- va->addr, va->addr + va->size, va->caller);
- pr_err("\n");
-
- page = vmalloc_to_page(addr);
- } else {
- pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr);
- }
+ pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr);
+ page = vmalloc_to_page(addr);
}
if (page) {
The patch below does not apply to the 6.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.15.y
git checkout FETCH_HEAD
git cherry-pick -x 52e1a03e6cf61ae165f59f41c44394a653a0a788
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025071203-dime-overcook-61dc@gregkh' --subject-prefix 'PATCH 6.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 52e1a03e6cf61ae165f59f41c44394a653a0a788 Mon Sep 17 00:00:00 2001
From: Nikunj A Dadhania <nikunj(a)amd.com>
Date: Mon, 30 Jun 2025 13:48:58 +0530
Subject: [PATCH] x86/sev: Use TSC_FACTOR for Secure TSC frequency calculation
When using Secure TSC, the GUEST_TSC_FREQ MSR reports a frequency based on
the nominal P0 frequency, which deviates slightly (typically ~0.2%) from
the actual mean TSC frequency due to clocking parameters.
Over extended VM uptime, this discrepancy accumulates, causing clock skew
between the hypervisor and a SEV-SNP VM, leading to early timer interrupts as
perceived by the guest.
The guest kernel relies on the reported nominal frequency for TSC-based
timekeeping, while the actual frequency set during SNP_LAUNCH_START may
differ. This mismatch results in inaccurate time calculations, causing the
guest to perceive hrtimers as firing earlier than expected.
Utilize the TSC_FACTOR from the SEV firmware's secrets page (see "Secrets
Page Format" in the SNP Firmware ABI Specification) to calculate the mean
TSC frequency, ensuring accurate timekeeping and mitigating clock skew in
SEV-SNP VMs.
Use early_ioremap_encrypted() to map the secrets page as
ioremap_encrypted() uses kmalloc() which is not available during early TSC
initialization and causes a panic.
[ bp: Drop the silly dummy var:
https://lore.kernel.org/r/20250630192726.GBaGLlHl84xIopx4Pt@fat_crate.local ]
Fixes: 73bbf3b0fbba ("x86/tsc: Init the TSC for Secure TSC guests")
Signed-off-by: Nikunj A Dadhania <nikunj(a)amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de>
Cc: stable(a)vger.kernel.org
Link: https://lore.kernel.org/20250630081858.485187-1-nikunj@amd.com
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index b6db4e0b936b..7543a8b52c67 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -88,7 +88,7 @@ static const char * const sev_status_feat_names[] = {
*/
static u64 snp_tsc_scale __ro_after_init;
static u64 snp_tsc_offset __ro_after_init;
-static u64 snp_tsc_freq_khz __ro_after_init;
+static unsigned long snp_tsc_freq_khz __ro_after_init;
DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data);
DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa);
@@ -2167,15 +2167,31 @@ static unsigned long securetsc_get_tsc_khz(void)
void __init snp_secure_tsc_init(void)
{
- unsigned long long tsc_freq_mhz;
+ struct snp_secrets_page *secrets;
+ unsigned long tsc_freq_mhz;
+ void *mem;
if (!cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC))
return;
+ mem = early_memremap_encrypted(sev_secrets_pa, PAGE_SIZE);
+ if (!mem) {
+ pr_err("Unable to get TSC_FACTOR: failed to map the SNP secrets page.\n");
+ sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECURE_TSC);
+ }
+
+ secrets = (__force struct snp_secrets_page *)mem;
+
setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
rdmsrq(MSR_AMD64_GUEST_TSC_FREQ, tsc_freq_mhz);
- snp_tsc_freq_khz = (unsigned long)(tsc_freq_mhz * 1000);
+
+ /* Extract the GUEST TSC MHZ from BIT[17:0], rest is reserved space */
+ tsc_freq_mhz &= GENMASK_ULL(17, 0);
+
+ snp_tsc_freq_khz = SNP_SCALE_TSC_FREQ(tsc_freq_mhz * 1000, secrets->tsc_factor);
x86_platform.calibrate_cpu = securetsc_get_tsc_khz;
x86_platform.calibrate_tsc = securetsc_get_tsc_khz;
+
+ early_memunmap(mem, PAGE_SIZE);
}
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 58e028d42e41..a631f7d7c0c0 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -223,6 +223,18 @@ struct snp_tsc_info_resp {
u8 rsvd2[100];
} __packed;
+/*
+ * Obtain the mean TSC frequency by decreasing the nominal TSC frequency with
+ * TSC_FACTOR as documented in the SNP Firmware ABI specification:
+ *
+ * GUEST_TSC_FREQ * (1 - (TSC_FACTOR * 0.00001))
+ *
+ * which is equivalent to:
+ *
+ * GUEST_TSC_FREQ -= (GUEST_TSC_FREQ * TSC_FACTOR) / 100000;
+ */
+#define SNP_SCALE_TSC_FREQ(freq, factor) ((freq) - (freq) * (factor) / 100000)
+
struct snp_guest_req {
void *req_buf;
size_t req_sz;
@@ -282,8 +294,11 @@ struct snp_secrets_page {
u8 svsm_guest_vmpl;
u8 rsvd3[3];
+ /* The percentage decrease from nominal to mean TSC frequency. */
+ u32 tsc_factor;
+
/* Remainder of page */
- u8 rsvd4[3744];
+ u8 rsvd4[3740];
} __packed;
struct snp_msg_desc {