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[PATCH 5.15.y] mptcp: set remote_deny_join_id0 on SYN recv

by Matthieu Baerts (NGI0)

commit 96939cec994070aa5df852c10fad5fc303a97ea3 upstream. When a SYN containing the 'C' flag (deny join id0) was received, this piece of information was not propagated to the path-manager. Even if this flag is mainly set on the server side, a client can also tell the server it cannot try to establish new subflows to the client's initial IP address and port. The server's PM should then record such info when received, and before sending events about the new connection. Fixes: df377be38725 ("mptcp: add deny_join_id0 in mptcp_options_received") Reviewed-by: Mat Martineau <martineau(a)kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-1-40… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> [ Conflicts in subflow.c, because of differences in the context, e.g. introduced by commit 3a236aef280e ("mptcp: refactor passive socket initialization"), which is not in this version. The same lines -- using 'mptcp_sk(new_msk)' instead of 'owner' -- can still be added approximately at the same place, before calling mptcp_pm_new_connection(). ] Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> --- net/mptcp/subflow.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 6bc36132d490..f67d8c98d58a 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -758,6 +758,9 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, */ WRITE_ONCE(mptcp_sk(new_msk)->first, child); + if (mp_opt.deny_join_id0) + WRITE_ONCE(mptcp_sk(new_msk)->pm.remote_deny_join_id0, true); + /* new mpc subflow takes ownership of the newly * created mptcp socket */ -- 2.51.0

3 months, 2 weeks

[PATCH] drm/xe/uapi: loosen used tracking restriction

by Matthew Auld

Currently this is hidden behind perfmon_capable() since this is technically an info leak, given that this is a system wide metric. However the granularity reported here is always PAGE_SIZE aligned, which matches what the core kernel is already willing to expose to userspace if querying how many free RAM pages there are on the system, and that doesn't need any special privileges. In addition other drm drivers seem happy to expose this. The motivation here if with oneAPI where they want to use the system wide 'used' reporting here, so not the per-client fdinfo stats. This has also come up with some perf overlay applications wanting this information. Fixes: 1105ac15d2a1 ("drm/xe/uapi: restrict system wide accounting") Signed-off-by: Matthew Auld <matthew.auld(a)intel.com> Cc: Thomas Hellström <thomas.hellstrom(a)linux.intel.com> Cc: Joshua Santosh <joshua.santosh.ranjan(a)intel.com> Cc: José Roberto de Souza <jose.souza(a)intel.com> Cc: Matthew Brost <matthew.brost(a)intel.com> Cc: Rodrigo Vivi <rodrigo.vivi(a)intel.com> Cc: <stable(a)vger.kernel.org> # v6.8+ --- drivers/gpu/drm/xe/xe_query.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c index e1b603aba61b..2e9ff33ed2fe 100644 --- a/drivers/gpu/drm/xe/xe_query.c +++ b/drivers/gpu/drm/xe/xe_query.c @@ -276,8 +276,7 @@ static int query_mem_regions(struct xe_device *xe, mem_regions->mem_regions[0].instance = 0; mem_regions->mem_regions[0].min_page_size = PAGE_SIZE; mem_regions->mem_regions[0].total_size = man->size << PAGE_SHIFT; - if (perfmon_capable()) - mem_regions->mem_regions[0].used = ttm_resource_manager_usage(man); + mem_regions->mem_regions[0].used = ttm_resource_manager_usage(man); mem_regions->num_mem_regions = 1; for (i = XE_PL_VRAM0; i <= XE_PL_VRAM1; ++i) { @@ -293,13 +292,11 @@ static int query_mem_regions(struct xe_device *xe, mem_regions->mem_regions[mem_regions->num_mem_regions].total_size = man->size; - if (perfmon_capable()) { - xe_ttm_vram_get_used(man, - &mem_regions->mem_regions - [mem_regions->num_mem_regions].used, - &mem_regions->mem_regions - [mem_regions->num_mem_regions].cpu_visible_used); - } + xe_ttm_vram_get_used(man, + &mem_regions->mem_regions + [mem_regions->num_mem_regions].used, + &mem_regions->mem_regions + [mem_regions->num_mem_regions].cpu_visible_used); mem_regions->mem_regions[mem_regions->num_mem_regions].cpu_visible_size = xe_ttm_vram_get_cpu_visible_size(man); -- 2.51.0

3 months, 2 weeks

[PATCH 6.1.y 0/2] mptcp: fix recent failed backports (20250919)

by Matthieu Baerts (NGI0)

The following patches could not be applied without conflicts in this tree: - 2293c57484ae ("mptcp: pm: nl: announce deny-join-id0 flag") - 24733e193a0d ("selftests: mptcp: userspace pm: validate deny-join-id0 flag") Conflicts have been resolved, and documented in each patch. Matthieu Baerts (NGI0) (2): mptcp: pm: nl: announce deny-join-id0 flag selftests: mptcp: userspace pm: validate deny-join-id0 flag include/uapi/linux/mptcp.h | 6 ++++-- net/mptcp/pm_netlink.c | 7 +++++++ tools/testing/selftests/net/mptcp/pm_nl_ctl.c | 7 +++++++ tools/testing/selftests/net/mptcp/userspace_pm.sh | 14 ++++++++++++-- 4 files changed, 30 insertions(+), 4 deletions(-) -- 2.51.0

3 months, 2 weeks

[PATCH 6.12.y] mptcp: pm: nl: announce deny-join-id0 flag

by Matthieu Baerts (NGI0)

commit 2293c57484ae64c9a3c847c8807db8c26a3a4d41 upstream. During the connection establishment, a peer can tell the other one that it cannot establish new subflows to the initial IP address and port by setting the 'C' flag [1]. Doing so makes sense when the sender is behind a strict NAT, operating behind a legacy Layer 4 load balancer, or using anycast IP address for example. When this 'C' flag is set, the path-managers must then not try to establish new subflows to the other peer's initial IP address and port. The in-kernel PM has access to this info, but the userspace PM didn't. The RFC8684 [1] is strict about that: (...) therefore the receiver MUST NOT try to open any additional subflows toward this address and port. So it is important to tell the userspace about that as it is responsible for the respect of this flag. When a new connection is created and established, the Netlink events now contain the existing but not currently used 'flags' attribute. When MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 is set, it means no other subflows to the initial IP address and port -- info that are also part of the event -- can be established. Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.1-20.6 [1] Fixes: 702c2f646d42 ("mptcp: netlink: allow userspace-driven subflow establishment") Reported-by: Marek Majkowski <marek(a)cloudflare.com> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/532 Reviewed-by: Mat Martineau <martineau(a)kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-2-40… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> [ Conflicts in mptcp_pm.yaml, because the indentation has been modified in commit ec362192aa9e ("netlink: specs: fix up indentation errors"), which is not in this version. Applying the same modifications, but at a different level. ] Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> --- Documentation/netlink/specs/mptcp_pm.yaml | 4 ++-- include/uapi/linux/mptcp.h | 2 ++ include/uapi/linux/mptcp_pm.h | 4 ++-- net/mptcp/pm_netlink.c | 7 +++++++ 4 files changed, 13 insertions(+), 4 deletions(-) diff --git a/Documentation/netlink/specs/mptcp_pm.yaml b/Documentation/netlink/specs/mptcp_pm.yaml index 7e295bad8b29..a670a9bbe01b 100644 --- a/Documentation/netlink/specs/mptcp_pm.yaml +++ b/Documentation/netlink/specs/mptcp_pm.yaml @@ -28,13 +28,13 @@ definitions: traffic-patterns it can take a long time until the MPTCP_EVENT_ESTABLISHED is sent. Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport, - dport, server-side. + dport, server-side, [flags]. - name: established doc: >- A MPTCP connection is established (can start new subflows). Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport, - dport, server-side. + dport, server-side, [flags]. - name: closed doc: >- diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h index 67d015df8893..5fd5b4cf75ca 100644 --- a/include/uapi/linux/mptcp.h +++ b/include/uapi/linux/mptcp.h @@ -31,6 +31,8 @@ #define MPTCP_INFO_FLAG_FALLBACK _BITUL(0) #define MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED _BITUL(1) +#define MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 _BITUL(0) + #define MPTCP_PM_ADDR_FLAG_SIGNAL (1 << 0) #define MPTCP_PM_ADDR_FLAG_SUBFLOW (1 << 1) #define MPTCP_PM_ADDR_FLAG_BACKUP (1 << 2) diff --git a/include/uapi/linux/mptcp_pm.h b/include/uapi/linux/mptcp_pm.h index 6ac84b2f636c..7359d34da446 100644 --- a/include/uapi/linux/mptcp_pm.h +++ b/include/uapi/linux/mptcp_pm.h @@ -16,10 +16,10 @@ * good time to allocate memory and send ADD_ADDR if needed. Depending on the * traffic-patterns it can take a long time until the MPTCP_EVENT_ESTABLISHED * is sent. Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, - * sport, dport, server-side. + * sport, dport, server-side, [flags]. * @MPTCP_EVENT_ESTABLISHED: A MPTCP connection is established (can start new * subflows). Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, - * sport, dport, server-side. + * sport, dport, server-side, [flags]. * @MPTCP_EVENT_CLOSED: A MPTCP connection has stopped. Attribute: token. * @MPTCP_EVENT_ANNOUNCED: A new address has been announced by the peer. * Attributes: token, rem_id, family, daddr4 | daddr6 [, dport]. diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index b763729b85e0..463c2e7956d5 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -2211,6 +2211,7 @@ static int mptcp_event_created(struct sk_buff *skb, const struct sock *ssk) { int err = nla_put_u32(skb, MPTCP_ATTR_TOKEN, READ_ONCE(msk->token)); + u16 flags = 0; if (err) return err; @@ -2218,6 +2219,12 @@ static int mptcp_event_created(struct sk_buff *skb, if (nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, READ_ONCE(msk->pm.server_side))) return -EMSGSIZE; + if (READ_ONCE(msk->pm.remote_deny_join_id0)) + flags |= MPTCP_PM_EV_FLAG_DENY_JOIN_ID0; + + if (flags && nla_put_u16(skb, MPTCP_ATTR_FLAGS, flags)) + return -EMSGSIZE; + return mptcp_event_add_subflow(skb, ssk); } -- 2.51.0

3 months, 2 weeks

[PATCH 6.16.y] mptcp: pm: nl: announce deny-join-id0 flag

by Matthieu Baerts (NGI0)

commit 2293c57484ae64c9a3c847c8807db8c26a3a4d41 upstream. During the connection establishment, a peer can tell the other one that it cannot establish new subflows to the initial IP address and port by setting the 'C' flag [1]. Doing so makes sense when the sender is behind a strict NAT, operating behind a legacy Layer 4 load balancer, or using anycast IP address for example. When this 'C' flag is set, the path-managers must then not try to establish new subflows to the other peer's initial IP address and port. The in-kernel PM has access to this info, but the userspace PM didn't. The RFC8684 [1] is strict about that: (...) therefore the receiver MUST NOT try to open any additional subflows toward this address and port. So it is important to tell the userspace about that as it is responsible for the respect of this flag. When a new connection is created and established, the Netlink events now contain the existing but not currently used 'flags' attribute. When MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 is set, it means no other subflows to the initial IP address and port -- info that are also part of the event -- can be established. Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.1-20.6 [1] Fixes: 702c2f646d42 ("mptcp: netlink: allow userspace-driven subflow establishment") Reported-by: Marek Majkowski <marek(a)cloudflare.com> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/532 Reviewed-by: Mat Martineau <martineau(a)kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-2-40… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> [ Conflicts in mptcp_pm.yaml, because the indentation has been modified in commit ec362192aa9e ("netlink: specs: fix up indentation errors"), which is not in this version. Applying the same modifications, but at a different level. ] Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> --- Documentation/netlink/specs/mptcp_pm.yaml | 4 ++-- include/uapi/linux/mptcp.h | 2 ++ include/uapi/linux/mptcp_pm.h | 4 ++-- net/mptcp/pm_netlink.c | 7 +++++++ 4 files changed, 13 insertions(+), 4 deletions(-) diff --git a/Documentation/netlink/specs/mptcp_pm.yaml b/Documentation/netlink/specs/mptcp_pm.yaml index ecfe5ee33de2..c77f32cfcae9 100644 --- a/Documentation/netlink/specs/mptcp_pm.yaml +++ b/Documentation/netlink/specs/mptcp_pm.yaml @@ -28,13 +28,13 @@ definitions: traffic-patterns it can take a long time until the MPTCP_EVENT_ESTABLISHED is sent. Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport, - dport, server-side. + dport, server-side, [flags]. - name: established doc: >- A MPTCP connection is established (can start new subflows). Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport, - dport, server-side. + dport, server-side, [flags]. - name: closed doc: >- diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h index 67d015df8893..5fd5b4cf75ca 100644 --- a/include/uapi/linux/mptcp.h +++ b/include/uapi/linux/mptcp.h @@ -31,6 +31,8 @@ #define MPTCP_INFO_FLAG_FALLBACK _BITUL(0) #define MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED _BITUL(1) +#define MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 _BITUL(0) + #define MPTCP_PM_ADDR_FLAG_SIGNAL (1 << 0) #define MPTCP_PM_ADDR_FLAG_SUBFLOW (1 << 1) #define MPTCP_PM_ADDR_FLAG_BACKUP (1 << 2) diff --git a/include/uapi/linux/mptcp_pm.h b/include/uapi/linux/mptcp_pm.h index 6ac84b2f636c..7359d34da446 100644 --- a/include/uapi/linux/mptcp_pm.h +++ b/include/uapi/linux/mptcp_pm.h @@ -16,10 +16,10 @@ * good time to allocate memory and send ADD_ADDR if needed. Depending on the * traffic-patterns it can take a long time until the MPTCP_EVENT_ESTABLISHED * is sent. Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, - * sport, dport, server-side. + * sport, dport, server-side, [flags]. * @MPTCP_EVENT_ESTABLISHED: A MPTCP connection is established (can start new * subflows). Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, - * sport, dport, server-side. + * sport, dport, server-side, [flags]. * @MPTCP_EVENT_CLOSED: A MPTCP connection has stopped. Attribute: token. * @MPTCP_EVENT_ANNOUNCED: A new address has been announced by the peer. * Attributes: token, rem_id, family, daddr4 | daddr6 [, dport]. diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 50aaf259959a..ce7d42d3bd00 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -408,6 +408,7 @@ static int mptcp_event_created(struct sk_buff *skb, const struct sock *ssk) { int err = nla_put_u32(skb, MPTCP_ATTR_TOKEN, READ_ONCE(msk->token)); + u16 flags = 0; if (err) return err; @@ -415,6 +416,12 @@ static int mptcp_event_created(struct sk_buff *skb, if (nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, READ_ONCE(msk->pm.server_side))) return -EMSGSIZE; + if (READ_ONCE(msk->pm.remote_deny_join_id0)) + flags |= MPTCP_PM_EV_FLAG_DENY_JOIN_ID0; + + if (flags && nla_put_u16(skb, MPTCP_ATTR_FLAGS, flags)) + return -EMSGSIZE; + return mptcp_event_add_subflow(skb, ssk); } -- 2.51.0

3 months, 2 weeks

stable: queue/* branches no longer updated

by Matthieu Baerts

Hi Sasha, Thank you for maintaining the stable versions with Greg! If I remember well, you run some scripts on your side to maintain the queue/* branches in the linux-stable-rc Git tree [1], is that correct? These branches have not been updated for a bit more than 3 weeks. Is it normal? Personally, I find them useful. But if it is just me, I can work without them. [1] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/… Cheers, Matt -- Sponsored by the NGI0 Core fund.

3 months, 2 weeks

+ kmsan-fix-out-of-bounds-access-to-shadow-memory.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: kmsan: Fix out-of-bounds access to shadow memory has been added to the -mm mm-hotfixes-unstable branch. Its filename is kmsan-fix-out-of-bounds-access-to-shadow-memory.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Eric Biggers <ebiggers(a)kernel.org> Subject: kmsan: Fix out-of-bounds access to shadow memory Date: Thu, 11 Sep 2025 12:58:58 -0700 Running sha224_kunit on a KMSAN-enabled kernel results in a crash in kmsan_internal_set_shadow_origin(): BUG: unable to handle page fault for address: ffffbc3840291000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary) Tainted: [N]=TEST Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100 [...] Call Trace: <TASK> __msan_memset+0xee/0x1a0 sha224_final+0x9e/0x350 test_hash_buffer_overruns+0x46f/0x5f0 ? kmsan_get_shadow_origin_ptr+0x46/0xa0 ? __pfx_test_hash_buffer_overruns+0x10/0x10 kunit_try_run_case+0x198/0xa00 This occurs when memset() is called on a buffer that is not 4-byte aligned and extends to the end of a guard page, i.e. the next page is unmapped. The bug is that the loop at the end of kmsan_internal_set_shadow_origin() accesses the wrong shadow memory bytes when the address is not 4-byte aligned. Since each 4 bytes are associated with an origin, it rounds the address and size so that it can access all the origins that contain the buffer. However, when it checks the corresponding shadow bytes for a particular origin, it incorrectly uses the original unrounded shadow address. This results in reads from shadow memory beyond the end of the buffer's shadow memory, which crashes when that memory is not mapped. To fix this, correctly align the shadow address before accessing the 4 shadow bytes corresponding to each origin. Link: https://lkml.kernel.org/r/20250911195858.394235-1-ebiggers@kernel.org Fixes: 2ef3cec44c60 ("kmsan: do not wipe out origin when doing partial unpoisoning") Signed-off-by: Eric Biggers <ebiggers(a)kernel.org> Tested-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Alexander Potapenko <glider(a)google.com> Cc: Dmitriy Vyukov <dvyukov(a)google.com> Cc: Marco Elver <elver(a)google.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/kmsan/core.c | 10 +++++++--- mm/kmsan/kmsan_test.c | 16 ++++++++++++++++ 2 files changed, 23 insertions(+), 3 deletions(-) --- a/mm/kmsan/core.c~kmsan-fix-out-of-bounds-access-to-shadow-memory +++ a/mm/kmsan/core.c @@ -195,7 +195,8 @@ void kmsan_internal_set_shadow_origin(vo u32 origin, bool checked) { u64 address = (u64)addr; - u32 *shadow_start, *origin_start; + void *shadow_start; + u32 *aligned_shadow, *origin_start; size_t pad = 0; KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(addr, size)); @@ -214,9 +215,12 @@ void kmsan_internal_set_shadow_origin(vo } __memset(shadow_start, b, size); - if (!IS_ALIGNED(address, KMSAN_ORIGIN_SIZE)) { + if (IS_ALIGNED(address, KMSAN_ORIGIN_SIZE)) { + aligned_shadow = shadow_start; + } else { pad = address % KMSAN_ORIGIN_SIZE; address -= pad; + aligned_shadow = shadow_start - pad; size += pad; } size = ALIGN(size, KMSAN_ORIGIN_SIZE); @@ -230,7 +234,7 @@ void kmsan_internal_set_shadow_origin(vo * corresponding shadow slot is zero. */ for (int i = 0; i < size / KMSAN_ORIGIN_SIZE; i++) { - if (origin || !shadow_start[i]) + if (origin || !aligned_shadow[i]) origin_start[i] = origin; } } --- a/mm/kmsan/kmsan_test.c~kmsan-fix-out-of-bounds-access-to-shadow-memory +++ a/mm/kmsan/kmsan_test.c @@ -556,6 +556,21 @@ DEFINE_TEST_MEMSETXX(16) DEFINE_TEST_MEMSETXX(32) DEFINE_TEST_MEMSETXX(64) +/* Test case: ensure that KMSAN does not access shadow memory out of bounds. */ +static void test_memset_on_guarded_buffer(struct kunit *test) +{ + void *buf = vmalloc(PAGE_SIZE); + + kunit_info(test, + "memset() on ends of guarded buffer should not crash\n"); + + for (size_t size = 0; size <= 128; size++) { + memset(buf, 0xff, size); + memset(buf + PAGE_SIZE - size, 0xff, size); + } + vfree(buf); +} + static noinline void fibonacci(int *array, int size, int start) { if (start < 2 || (start == size)) @@ -677,6 +692,7 @@ static struct kunit_case kmsan_test_case KUNIT_CASE(test_memset16), KUNIT_CASE(test_memset32), KUNIT_CASE(test_memset64), + KUNIT_CASE(test_memset_on_guarded_buffer), KUNIT_CASE(test_long_origin_chain), KUNIT_CASE(test_stackdepot_roundtrip), KUNIT_CASE(test_unpoison_memory), _ Patches currently in -mm which might be from ebiggers(a)kernel.org are kmsan-fix-out-of-bounds-access-to-shadow-memory.patch

3 months, 2 weeks

+ squashfs-fix-uninit-value-in-squashfs_get_parent.patch added to mm-nonmm-unstable branch

by Andrew Morton

The patch titled Subject: Squashfs: fix uninit-value in squashfs_get_parent has been added to the -mm mm-nonmm-unstable branch. Its filename is squashfs-fix-uninit-value-in-squashfs_get_parent.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Phillip Lougher <phillip(a)squashfs.org.uk> Subject: Squashfs: fix uninit-value in squashfs_get_parent Date: Fri, 19 Sep 2025 00:33:08 +0100 Syzkaller reports a "KMSAN: uninit-value in squashfs_get_parent" bug. This is caused by open_by_handle_at() being called with a file handle containing an invalid parent inode number. In particular the inode number is that of a symbolic link, rather than a directory. Squashfs_get_parent() gets called with that symbolic link inode, and accesses the parent member field. unsigned int parent_ino = squashfs_i(inode)->parent; Because non-directory inodes in Squashfs do not have a parent value, this is uninitialised, and this causes an uninitialised value access. The fix is to initialise parent with the invalid inode 0, which will cause an EINVAL error to be returned. Regular inodes used to share the parent field with the block_list_start field. This is removed in this commit to enable the parent field to contain the invalid inode number 0. Link: https://lkml.kernel.org/r/20250918233308.293861-1-phillip@squashfs.org.uk Fixes: 122601408d20 ("Squashfs: export operations") Signed-off-by: Phillip Lougher <phillip(a)squashfs.org.uk> Reported-by: syzbot+157bdef5cf596ad0da2c(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68cc2431.050a0220.139b6.0001.GAE@google.com/ Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/squashfs/inode.c | 7 +++++++ fs/squashfs/squashfs_fs_i.h | 2 +- 2 files changed, 8 insertions(+), 1 deletion(-) --- a/fs/squashfs/inode.c~squashfs-fix-uninit-value-in-squashfs_get_parent +++ a/fs/squashfs/inode.c @@ -169,6 +169,7 @@ int squashfs_read_inode(struct inode *in squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); squashfs_i(inode)->block_list_start = block; squashfs_i(inode)->offset = offset; + squashfs_i(inode)->parent = 0; inode->i_data.a_ops = &squashfs_aops; TRACE("File inode %x:%x, start_block %llx, block_list_start " @@ -216,6 +217,7 @@ int squashfs_read_inode(struct inode *in squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block); squashfs_i(inode)->block_list_start = block; squashfs_i(inode)->offset = offset; + squashfs_i(inode)->parent = 0; inode->i_data.a_ops = &squashfs_aops; TRACE("File inode %x:%x, start_block %llx, block_list_start " @@ -296,6 +298,7 @@ int squashfs_read_inode(struct inode *in inode->i_mode |= S_IFLNK; squashfs_i(inode)->start = block; squashfs_i(inode)->offset = offset; + squashfs_i(inode)->parent = 0; if (type == SQUASHFS_LSYMLINK_TYPE) { __le32 xattr; @@ -333,6 +336,7 @@ int squashfs_read_inode(struct inode *in set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); rdev = le32_to_cpu(sqsh_ino->rdev); init_special_inode(inode, inode->i_mode, new_decode_dev(rdev)); + squashfs_i(inode)->parent = 0; TRACE("Device inode %x:%x, rdev %x\n", SQUASHFS_INODE_BLK(ino), offset, rdev); @@ -357,6 +361,7 @@ int squashfs_read_inode(struct inode *in set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); rdev = le32_to_cpu(sqsh_ino->rdev); init_special_inode(inode, inode->i_mode, new_decode_dev(rdev)); + squashfs_i(inode)->parent = 0; TRACE("Device inode %x:%x, rdev %x\n", SQUASHFS_INODE_BLK(ino), offset, rdev); @@ -377,6 +382,7 @@ int squashfs_read_inode(struct inode *in inode->i_mode |= S_IFSOCK; set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); init_special_inode(inode, inode->i_mode, 0); + squashfs_i(inode)->parent = 0; break; } case SQUASHFS_LFIFO_TYPE: @@ -396,6 +402,7 @@ int squashfs_read_inode(struct inode *in inode->i_op = &squashfs_inode_ops; set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); init_special_inode(inode, inode->i_mode, 0); + squashfs_i(inode)->parent = 0; break; } default: --- a/fs/squashfs/squashfs_fs_i.h~squashfs-fix-uninit-value-in-squashfs_get_parent +++ a/fs/squashfs/squashfs_fs_i.h @@ -16,6 +16,7 @@ struct squashfs_inode_info { u64 xattr; unsigned int xattr_size; int xattr_count; + int parent; union { struct { u64 fragment_block; @@ -27,7 +28,6 @@ struct squashfs_inode_info { u64 dir_idx_start; int dir_idx_offset; int dir_idx_cnt; - int parent; }; }; struct inode vfs_inode; _ Patches currently in -mm which might be from phillip(a)squashfs.org.uk are squashfs-fix-uninit-value-in-squashfs_get_parent.patch

3 months, 2 weeks

+ fs-proc-task_mmu-check-cur_buf-for-null.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: fs/proc/task_mmu: check cur_buf for NULL has been added to the -mm mm-hotfixes-unstable branch. Its filename is fs-proc-task_mmu-check-cur_buf-for-null.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Jakub Acs <acsjakub(a)amazon.de> Subject: fs/proc/task_mmu: check cur_buf for NULL Date: Fri, 19 Sep 2025 14:21:04 +0000 When the PAGEMAP_SCAN ioctl is invoked with vec_len = 0 reaches pagemap_scan_backout_range(), kernel panics with null-ptr-deref: [ 44.936808] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI [ 44.937797] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] [ 44.938391] CPU: 1 UID: 0 PID: 2480 Comm: reproducer Not tainted 6.17.0-rc6 #22 PREEMPT(none) [ 44.939062] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 44.939935] RIP: 0010:pagemap_scan_thp_entry.isra.0+0x741/0xa80 <snip registers, unreliable trace> [ 44.946828] Call Trace: [ 44.947030] <TASK> [ 44.949219] pagemap_scan_pmd_entry+0xec/0xfa0 [ 44.952593] walk_pmd_range.isra.0+0x302/0x910 [ 44.954069] walk_pud_range.isra.0+0x419/0x790 [ 44.954427] walk_p4d_range+0x41e/0x620 [ 44.954743] walk_pgd_range+0x31e/0x630 [ 44.955057] __walk_page_range+0x160/0x670 [ 44.956883] walk_page_range_mm+0x408/0x980 [ 44.958677] walk_page_range+0x66/0x90 [ 44.958984] do_pagemap_scan+0x28d/0x9c0 [ 44.961833] do_pagemap_cmd+0x59/0x80 [ 44.962484] __x64_sys_ioctl+0x18d/0x210 [ 44.962804] do_syscall_64+0x5b/0x290 [ 44.963111] entry_SYSCALL_64_after_hwframe+0x76/0x7e vec_len = 0 in pagemap_scan_init_bounce_buffer() means no buffers are allocated and p->vec_buf remains set to NULL. This breaks an assumption made later in pagemap_scan_backout_range(), that page_region is always allocated for p->vec_buf_index. Fix it by explicitly checking cur_buf for NULL before dereferencing. Other sites that might run into same deref-issue are already (directly or transitively) protected by checking p->vec_buf. Note: From PAGEMAP_SCAN man page, it seems vec_len = 0 is valid when no output is requested and it's only the side effects caller is interested in, hence it passes check in pagemap_scan_get_args(). This issue was found by syzkaller. Link: https://lkml.kernel.org/r/20250919142106.43527-1-acsjakub@amazon.de Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs") Signed-off-by: Jakub Acs <acsjakub(a)amazon.de> Cc: David Hildenbrand <david(a)redhat.com> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Jinjiang Tu <tujinjiang(a)huawei.com> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Penglei Jiang <superman.xpt(a)gmail.com> Cc: Mark Brown <broonie(a)kernel.org> Cc: Baolin Wang <baolin.wang(a)linux.alibaba.com> Cc: Ryan Roberts <ryan.roberts(a)arm.com> Cc: Andrei Vagin <avagin(a)gmail.com> Cc: "Micha�� Miros��aw" <mirq-linux(a)rere.qmqm.pl> Cc: Stephen Rothwell <sfr(a)canb.auug.org.au> Cc: Muhammad Usama Anjum <usama.anjum(a)collabora.com> Cc: Alexey Dobriyan <adobriyan(a)gmail.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/proc/task_mmu.c | 3 +++ 1 file changed, 3 insertions(+) --- a/fs/proc/task_mmu.c~fs-proc-task_mmu-check-cur_buf-for-null +++ a/fs/proc/task_mmu.c @@ -2417,6 +2417,9 @@ static void pagemap_scan_backout_range(s { struct page_region *cur_buf = &p->vec_buf[p->vec_buf_index]; + if (!cur_buf) + return; + if (cur_buf->start != addr) cur_buf->end = addr; else _ Patches currently in -mm which might be from acsjakub(a)amazon.de are fs-proc-task_mmu-check-cur_buf-for-null.patch

3 months, 2 weeks

[PATCH 6.12.y 0/3] Fix a backport of VMSCAPE enumeration fix

by Harshit Mogalapalli

Bug-report: https://lore.kernel.org/all/915c0e00-b92d-4e37-9d4b-0f6a4580da97@oracle.com/ Summary: While backporting commit: 7c62c442b6eb ("x86/vmscape: Enumerate VMSCAPE bug") to 6.12.y --> VULNBL_AMD(0x1a, SRSO | VMSCAPE) was added even when 6.12.y doesn't have commit: 877818802c3e ("x86/bugs: Add SRSO_USER_KERNEL_NO support"). Boris Ostrovsky suggested backporting three commits to 6.12.y: 1. commit: 877818802c3e ("x86/bugs: Add SRSO_USER_KERNEL_NO support") 2. commit: 8442df2b49ed ("x86/bugs: KVM: Add support for SRSO_MSR_FIX") and its fix 3. commit: e3417ab75ab2 ("KVM: SVM: Set/clear SRSO's BP_SPEC_REDUCE on 0 <=> 1 VM count transitions") -- Maybe optional Which changes current mitigation status on turin for 6.12.48 from Safe RET to Reduced Speculation, leaving it with Safe RET liely causes heavy performance regressions. This three patches together change mitigation status from Safe RET to Reduced Speculation Tested on Turin: [ 3.188134] Speculative Return Stack Overflow: Mitigation: Reduced Speculation Backports: 1. Patch 1 had minor conflict as VMSCAPE commit added VULNBL_AMD(0x1a, SRSO | VMSCAPE), and resolution is to skip that line. 2. Patch 2 and 3 are clean cherry-picks, 3 is a fix for 2. Note: I verified if this problem is also on other stable trees like (6.6 --> 5.10, no they don't have this backport problem) Thanks, Harshit Borislav Petkov (1): x86/bugs: KVM: Add support for SRSO_MSR_FIX Borislav Petkov (AMD) (1): x86/bugs: Add SRSO_USER_KERNEL_NO support Sean Christopherson (1): KVM: SVM: Set/clear SRSO's BP_SPEC_REDUCE on 0 <=> 1 VM count transitions Documentation/admin-guide/hw-vuln/srso.rst | 13 +++++ arch/x86/include/asm/cpufeatures.h | 5 ++ arch/x86/include/asm/msr-index.h | 1 + arch/x86/kernel/cpu/bugs.c | 28 ++++++++-- arch/x86/kvm/svm/svm.c | 65 ++++++++++++++++++++++ arch/x86/kvm/svm/svm.h | 2 + arch/x86/lib/msr.c | 2 + 7 files changed, 112 insertions(+), 4 deletions(-) -- 2.50.1

3 months, 2 weeks

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