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[PATCH v2 OLK-6.6] vsock/virtio: cap TX credit to local buffer size
by Ze Zuo 07 Mar '26

07 Mar '26

From: Melbin K Mathew <mlbnkm1(a)gmail.com> stable inclusion from stable-v6.6.122 commit d9d5f222558b42f6277eafaaa6080966faf37676 category: feature bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13619 CVE: CVE-2026-23086 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 8ee784fdf006cbe8739cfa093f54d326cbf54037 ] The virtio transports derives its TX credit directly from peer_buf_alloc, which is set from the remote endpoint's SO_VM_SOCKETS_BUFFER_SIZE value. On the host side this means that the amount of data we are willing to queue for a connection is scaled by a guest-chosen buffer size, rather than the host's own vsock configuration. A malicious guest can advertise a large buffer and read slowly, causing the host to allocate a correspondingly large amount of sk_buff memory. The same thing would happen in the guest with a malicious host, since virtio transports share the same code base. Introduce a small helper, virtio_transport_tx_buf_size(), that returns min(peer_buf_alloc, buf_alloc), and use it wherever we consume peer_buf_alloc. This ensures the effective TX window is bounded by both the peer's advertised buffer and our own buf_alloc (already clamped to buffer_max_size via SO_VM_SOCKETS_BUFFER_MAX_SIZE), so a remote peer cannot force the other to queue more data than allowed by its own vsock settings. On an unpatched Ubuntu 22.04 host (~64 GiB RAM), running a PoC with 32 guest vsock connections advertising 2 GiB each and reading slowly drove Slab/SUnreclaim from ~0.5 GiB to ~57 GiB; the system only recovered after killing the QEMU process. That said, if QEMU memory is limited with cgroups, the maximum memory used will be limited. With this patch applied: Before: MemFree: ~61.6 GiB Slab: ~142 MiB SUnreclaim: ~117 MiB After 32 high-credit connections: MemFree: ~61.5 GiB Slab: ~178 MiB SUnreclaim: ~152 MiB Only ~35 MiB increase in Slab/SUnreclaim, no host OOM, and the guest remains responsive. Compatibility with non-virtio transports: - VMCI uses the AF_VSOCK buffer knobs to size its queue pairs per socket based on the local vsk->buffer_* values; the remote side cannot enlarge those queues beyond what the local endpoint configured. - Hyper-V's vsock transport uses fixed-size VMBus ring buffers and an MTU bound; there is no peer-controlled credit field comparable to peer_buf_alloc, and the remote endpoint cannot drive in-flight kernel memory above those ring sizes. - The loopback path reuses virtio_transport_common.c, so it naturally follows the same semantics as the virtio transport. This change is limited to virtio_transport_common.c and thus affects virtio-vsock, vhost-vsock, and loopback, bringing them in line with the "remote window intersected with local policy" behaviour that VMCI and Hyper-V already effectively have. Fixes: 06a8fc78367d ("VSOCK: Introduce virtio_vsock_common.ko") Suggested-by: Stefano Garzarella <sgarzare(a)redhat.com> Signed-off-by: Melbin K Mathew <mlbnkm1(a)gmail.com> [Stefano: small adjustments after changing the previous patch] [Stefano: tweak the commit message] Signed-off-by: Stefano Garzarella <sgarzare(a)redhat.com> Reviewed-by: Luigi Leonardi <leonardi(a)redhat.com> Link: https://patch.msgid.link/20260121093628.9941-4-sgarzare@redhat.com Acked-by: Michael S. Tsirkin <mst(a)redhat.com> Signed-off-by: Paolo Abeni <pabeni(a)redhat.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Conflicts: net/vmw_vsock/virtio_transport_common.c [Conflicts due to context.] Signed-off-by: Ze Zuo <zuoze1(a)huawei.com> --- change since v1: -- fix patch merge conflict. --- net/vmw_vsock/virtio_transport_common.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 1401177e2622..4c374c36c29d 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -628,6 +628,15 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk, } EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue); +static u32 virtio_transport_tx_buf_size(struct virtio_vsock_sock *vvs) +{ + /* The peer advertises its receive buffer via peer_buf_alloc, but we + * cap it to our local buf_alloc so a remote peer cannot force us to + * queue more data than our own buffer configuration allows. + */ + return min(vvs->peer_buf_alloc, vvs->buf_alloc); +} + int virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk, struct msghdr *msg, @@ -637,7 +646,7 @@ virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk, spin_lock_bh(&vvs->tx_lock); - if (len > vvs->peer_buf_alloc) { + if (len > virtio_transport_tx_buf_size(vvs)) { spin_unlock_bh(&vvs->tx_lock); return -EMSGSIZE; } @@ -691,7 +700,8 @@ static s64 virtio_transport_has_space(struct virtio_vsock_sock *vvs) * we have bytes in flight (tx_cnt - peer_fwd_cnt), the subtraction * does not underflow. */ - bytes = (s64)vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt); + bytes = (s64)virtio_transport_tx_buf_size(vvs) - + (vvs->tx_cnt - vvs->peer_fwd_cnt); if (bytes < 0) bytes = 0; -- 2.25.1

2 1

[PATCH OLK-6.6] Revert "mm: Move vm_cache_limit_mbytes check to page_cache_over_limit()"
by Ze Zuo 07 Mar '26

07 Mar '26

hulk inclusion category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13853 -------------------------------- This reverts commit 00b50cbb31ad11c0896355e351f961b1b586797f. Before this patch commit 00b50cbb31ad ("mm: Move vm_cache_limit_mbytes check to page_cache_over_limit()") was merged, setting cache_limit_mbytes to 0 meant that periodic reclaim could reclaim page cache without limitation. After the patch was merged, page cache is no longer reclaimed when cache_limit_mbytes is set to 0. As a result, periodic reclaim becomes ineffective. Revert this patch. Fixes: 00b50cbb31ad ("mm: Move vm_cache_limit_mbytes check to page_cache_over_limit()") Signed-off-by: Ze Zuo <zuoze1(a)huawei.com> --- mm/page_cache_limit.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/mm/page_cache_limit.c b/mm/page_cache_limit.c index 677ead24d27f..fe67b8b804f0 100644 --- a/mm/page_cache_limit.c +++ b/mm/page_cache_limit.c @@ -38,9 +38,6 @@ static bool page_cache_over_limit(void) unsigned long lru_file; unsigned long limit; - if (!vm_cache_limit_mbytes) - return false; - limit = vm_cache_limit_mbytes << (20 - PAGE_SHIFT); lru_file = global_node_page_state(NR_ACTIVE_FILE) + global_node_page_state(NR_INACTIVE_FILE); @@ -50,6 +47,17 @@ static bool page_cache_over_limit(void) return false; } +static bool should_reclaim_page_cache(void) +{ + if (!should_periodical_reclaim()) + return false; + + if (!vm_cache_limit_mbytes) + return false; + + return true; +} + int cache_reclaim_enable_handler(struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { @@ -102,7 +110,7 @@ int cache_limit_mbytes_sysctl_handler(struct ctl_table *table, int write, } if (write) { - while (should_periodical_reclaim() && page_cache_over_limit() && + while (should_reclaim_page_cache() && page_cache_over_limit() && nr_retries--) { if (signal_pending(current)) return -EINTR; -- 2.25.1

2 1

[PATCH OLK-5.10] kexec: derive purgatory entry from symbol
by Tengda Wu 06 Mar '26

06 Mar '26

From: Li Chen <me(a)linux.beauty> stable inclusion from stable-v5.10.252 commit 027797595a108726f4a0a45d225f603b0ffbd22b category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8682 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 480e1d5c64bb14441f79f2eb9421d5e26f91ea3d ] kexec_load_purgatory() derives image->start by locating e_entry inside an SHF_EXECINSTR section. If the purgatory object contains multiple executable sections with overlapping sh_addr, the entrypoint check can match more than once and trigger a WARN. Derive the entry section from the purgatory_start symbol when present and compute image->start from its final placement. Keep the existing e_entry fallback for purgatories that do not expose the symbol. WARNING: kernel/kexec_file.c:1009 at kexec_load_purgatory+0x395/0x3c0, CPU#10: kexec/1784 Call Trace: <TASK> bzImage64_load+0x133/0xa00 __do_sys_kexec_file_load+0x2b3/0x5c0 do_syscall_64+0x81/0x610 entry_SYSCALL_64_after_hwframe+0x76/0x7e [me(a)linux.beauty: move helper to avoid forward declaration, per Baoquan] Link: https://lkml.kernel.org/r/20260128043511.316860-1-me@linux.beauty Link: https://lkml.kernel.org/r/20260120124005.148381-1-me@linux.beauty Fixes: 8652d44f466a ("kexec: support purgatories with .text.hot sections") Signed-off-by: Li Chen <me(a)linux.beauty> Acked-by: Baoquan He <bhe(a)redhat.com> Cc: Alexander Graf <graf(a)amazon.com> Cc: Eric Biggers <ebiggers(a)kernel.org> Cc: Li Chen <me(a)linux.beauty> Cc: Philipp Rudo <prudo(a)redhat.com> Cc: Ricardo Ribalda Delgado <ribalda(a)chromium.org> Cc: Ross Zwisler <zwisler(a)google.com> Cc: Sourabh Jain <sourabhjain(a)linux.ibm.com> Cc: Steven Rostedt <rostedt(a)goodmis.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Tengda Wu <wutengda2(a)huawei.com> --- kernel/kexec_file.c | 131 +++++++++++++++++++++++++------------------- 1 file changed, 74 insertions(+), 57 deletions(-) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index a0919955a00b..ed372103b2f2 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -834,6 +834,60 @@ static int kexec_calculate_store_digests(struct kimage *image) } #ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY +/* + * kexec_purgatory_find_symbol - find a symbol in the purgatory + * @pi: Purgatory to search in. + * @name: Name of the symbol. + * + * Return: pointer to symbol in read-only symtab on success, NULL on error. + */ +static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, + const char *name) +{ + const Elf_Shdr *sechdrs; + const Elf_Ehdr *ehdr; + const Elf_Sym *syms; + const char *strtab; + int i, k; + + if (!pi->ehdr) + return NULL; + + ehdr = pi->ehdr; + sechdrs = (void *)ehdr + ehdr->e_shoff; + + for (i = 0; i < ehdr->e_shnum; i++) { + if (sechdrs[i].sh_type != SHT_SYMTAB) + continue; + + if (sechdrs[i].sh_link >= ehdr->e_shnum) + /* Invalid strtab section number */ + continue; + strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; + syms = (void *)ehdr + sechdrs[i].sh_offset; + + /* Go through symbols for a match */ + for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { + if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) + continue; + + if (strcmp(strtab + syms[k].st_name, name) != 0) + continue; + + if (syms[k].st_shndx == SHN_UNDEF || + syms[k].st_shndx >= ehdr->e_shnum) { + pr_debug("Symbol: %s has bad section index %d.\n", + name, syms[k].st_shndx); + return NULL; + } + + /* Found the symbol we are looking for */ + return &syms[k]; + } + } + + return NULL; +} /* * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory. * @pi: Purgatory to be loaded. @@ -911,6 +965,10 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, unsigned long bss_addr; unsigned long offset; Elf_Shdr *sechdrs; + const Elf_Sym *entry_sym; + u16 entry_shndx = 0; + unsigned long entry_off = 0; + bool start_fixed = false; int i; /* @@ -928,6 +986,12 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, bss_addr = kbuf->mem + kbuf->bufsz; kbuf->image->start = pi->ehdr->e_entry; + entry_sym = kexec_purgatory_find_symbol(pi, "purgatory_start"); + if (entry_sym) { + entry_shndx = entry_sym->st_shndx; + entry_off = entry_sym->st_value; + } + for (i = 0; i < pi->ehdr->e_shnum; i++) { unsigned long align; void *src, *dst; @@ -945,6 +1009,13 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, offset = ALIGN(offset, align); + if (!start_fixed && entry_sym && i == entry_shndx && + (sechdrs[i].sh_flags & SHF_EXECINSTR) && + entry_off < sechdrs[i].sh_size) { + kbuf->image->start = kbuf->mem + offset + entry_off; + start_fixed = true; + } + /* * Check if the segment contains the entry point, if so, * calculate the value of image->start based on it. @@ -955,13 +1026,14 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, * is not set to the initial value, and warn the user so they * have a chance to fix their purgatory's linker script. */ - if (sechdrs[i].sh_flags & SHF_EXECINSTR && + if (!start_fixed && sechdrs[i].sh_flags & SHF_EXECINSTR && pi->ehdr->e_entry >= sechdrs[i].sh_addr && pi->ehdr->e_entry < (sechdrs[i].sh_addr + sechdrs[i].sh_size) && - !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) { + kbuf->image->start == pi->ehdr->e_entry) { kbuf->image->start -= sechdrs[i].sh_addr; kbuf->image->start += kbuf->mem + offset; + start_fixed = true; } src = (void *)pi->ehdr + sechdrs[i].sh_offset; @@ -1079,61 +1151,6 @@ int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf) return ret; } -/* - * kexec_purgatory_find_symbol - find a symbol in the purgatory - * @pi: Purgatory to search in. - * @name: Name of the symbol. - * - * Return: pointer to symbol in read-only symtab on success, NULL on error. - */ -static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, - const char *name) -{ - const Elf_Shdr *sechdrs; - const Elf_Ehdr *ehdr; - const Elf_Sym *syms; - const char *strtab; - int i, k; - - if (!pi->ehdr) - return NULL; - - ehdr = pi->ehdr; - sechdrs = (void *)ehdr + ehdr->e_shoff; - - for (i = 0; i < ehdr->e_shnum; i++) { - if (sechdrs[i].sh_type != SHT_SYMTAB) - continue; - - if (sechdrs[i].sh_link >= ehdr->e_shnum) - /* Invalid strtab section number */ - continue; - strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; - syms = (void *)ehdr + sechdrs[i].sh_offset; - - /* Go through symbols for a match */ - for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { - if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) - continue; - - if (strcmp(strtab + syms[k].st_name, name) != 0) - continue; - - if (syms[k].st_shndx == SHN_UNDEF || - syms[k].st_shndx >= ehdr->e_shnum) { - pr_debug("Symbol: %s has bad section index %d.\n", - name, syms[k].st_shndx); - return NULL; - } - - /* Found the symbol we are looking for */ - return &syms[k]; - } - } - - return NULL; -} - void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) { struct purgatory_info *pi = &image->purgatory_info; -- 2.34.1

2 1

[PATCH OLK-6.6] kexec: derive purgatory entry from symbol
by Tengda Wu 06 Mar '26

06 Mar '26

From: Li Chen <me(a)linux.beauty> stable inclusion from stable-v6.6.129 commit cfccd3b8c51bc57a8a6fcb2fd30453afae5bc0d2 category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8682 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 480e1d5c64bb14441f79f2eb9421d5e26f91ea3d ] kexec_load_purgatory() derives image->start by locating e_entry inside an SHF_EXECINSTR section. If the purgatory object contains multiple executable sections with overlapping sh_addr, the entrypoint check can match more than once and trigger a WARN. Derive the entry section from the purgatory_start symbol when present and compute image->start from its final placement. Keep the existing e_entry fallback for purgatories that do not expose the symbol. WARNING: kernel/kexec_file.c:1009 at kexec_load_purgatory+0x395/0x3c0, CPU#10: kexec/1784 Call Trace: <TASK> bzImage64_load+0x133/0xa00 __do_sys_kexec_file_load+0x2b3/0x5c0 do_syscall_64+0x81/0x610 entry_SYSCALL_64_after_hwframe+0x76/0x7e [me(a)linux.beauty: move helper to avoid forward declaration, per Baoquan] Link: https://lkml.kernel.org/r/20260128043511.316860-1-me@linux.beauty Link: https://lkml.kernel.org/r/20260120124005.148381-1-me@linux.beauty Fixes: 8652d44f466a ("kexec: support purgatories with .text.hot sections") Signed-off-by: Li Chen <me(a)linux.beauty> Acked-by: Baoquan He <bhe(a)redhat.com> Cc: Alexander Graf <graf(a)amazon.com> Cc: Eric Biggers <ebiggers(a)kernel.org> Cc: Li Chen <me(a)linux.beauty> Cc: Philipp Rudo <prudo(a)redhat.com> Cc: Ricardo Ribalda Delgado <ribalda(a)chromium.org> Cc: Ross Zwisler <zwisler(a)google.com> Cc: Sourabh Jain <sourabhjain(a)linux.ibm.com> Cc: Steven Rostedt <rostedt(a)goodmis.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Tengda Wu <wutengda2(a)huawei.com> --- kernel/kexec_file.c | 131 +++++++++++++++++++++++++------------------- 1 file changed, 74 insertions(+), 57 deletions(-) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 830344627e9f..92a169f0b2b5 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -797,6 +797,60 @@ static int kexec_calculate_store_digests(struct kimage *image) } #ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY +/* + * kexec_purgatory_find_symbol - find a symbol in the purgatory + * @pi: Purgatory to search in. + * @name: Name of the symbol. + * + * Return: pointer to symbol in read-only symtab on success, NULL on error. + */ +static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, + const char *name) +{ + const Elf_Shdr *sechdrs; + const Elf_Ehdr *ehdr; + const Elf_Sym *syms; + const char *strtab; + int i, k; + + if (!pi->ehdr) + return NULL; + + ehdr = pi->ehdr; + sechdrs = (void *)ehdr + ehdr->e_shoff; + + for (i = 0; i < ehdr->e_shnum; i++) { + if (sechdrs[i].sh_type != SHT_SYMTAB) + continue; + + if (sechdrs[i].sh_link >= ehdr->e_shnum) + /* Invalid strtab section number */ + continue; + strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; + syms = (void *)ehdr + sechdrs[i].sh_offset; + + /* Go through symbols for a match */ + for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { + if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) + continue; + + if (strcmp(strtab + syms[k].st_name, name) != 0) + continue; + + if (syms[k].st_shndx == SHN_UNDEF || + syms[k].st_shndx >= ehdr->e_shnum) { + pr_debug("Symbol: %s has bad section index %d.\n", + name, syms[k].st_shndx); + return NULL; + } + + /* Found the symbol we are looking for */ + return &syms[k]; + } + } + + return NULL; +} /* * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory. * @pi: Purgatory to be loaded. @@ -875,6 +929,10 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, unsigned long offset; size_t sechdrs_size; Elf_Shdr *sechdrs; + const Elf_Sym *entry_sym; + u16 entry_shndx = 0; + unsigned long entry_off = 0; + bool start_fixed = false; int i; /* @@ -892,6 +950,12 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, bss_addr = kbuf->mem + kbuf->bufsz; kbuf->image->start = pi->ehdr->e_entry; + entry_sym = kexec_purgatory_find_symbol(pi, "purgatory_start"); + if (entry_sym) { + entry_shndx = entry_sym->st_shndx; + entry_off = entry_sym->st_value; + } + for (i = 0; i < pi->ehdr->e_shnum; i++) { unsigned long align; void *src, *dst; @@ -909,6 +973,13 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, offset = ALIGN(offset, align); + if (!start_fixed && entry_sym && i == entry_shndx && + (sechdrs[i].sh_flags & SHF_EXECINSTR) && + entry_off < sechdrs[i].sh_size) { + kbuf->image->start = kbuf->mem + offset + entry_off; + start_fixed = true; + } + /* * Check if the segment contains the entry point, if so, * calculate the value of image->start based on it. @@ -919,13 +990,14 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, * is not set to the initial value, and warn the user so they * have a chance to fix their purgatory's linker script. */ - if (sechdrs[i].sh_flags & SHF_EXECINSTR && + if (!start_fixed && sechdrs[i].sh_flags & SHF_EXECINSTR && pi->ehdr->e_entry >= sechdrs[i].sh_addr && pi->ehdr->e_entry < (sechdrs[i].sh_addr + sechdrs[i].sh_size) && - !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) { + kbuf->image->start == pi->ehdr->e_entry) { kbuf->image->start -= sechdrs[i].sh_addr; kbuf->image->start += kbuf->mem + offset; + start_fixed = true; } src = (void *)pi->ehdr + sechdrs[i].sh_offset; @@ -1043,61 +1115,6 @@ int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf) return ret; } -/* - * kexec_purgatory_find_symbol - find a symbol in the purgatory - * @pi: Purgatory to search in. - * @name: Name of the symbol. - * - * Return: pointer to symbol in read-only symtab on success, NULL on error. - */ -static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, - const char *name) -{ - const Elf_Shdr *sechdrs; - const Elf_Ehdr *ehdr; - const Elf_Sym *syms; - const char *strtab; - int i, k; - - if (!pi->ehdr) - return NULL; - - ehdr = pi->ehdr; - sechdrs = (void *)ehdr + ehdr->e_shoff; - - for (i = 0; i < ehdr->e_shnum; i++) { - if (sechdrs[i].sh_type != SHT_SYMTAB) - continue; - - if (sechdrs[i].sh_link >= ehdr->e_shnum) - /* Invalid strtab section number */ - continue; - strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; - syms = (void *)ehdr + sechdrs[i].sh_offset; - - /* Go through symbols for a match */ - for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { - if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) - continue; - - if (strcmp(strtab + syms[k].st_name, name) != 0) - continue; - - if (syms[k].st_shndx == SHN_UNDEF || - syms[k].st_shndx >= ehdr->e_shnum) { - pr_debug("Symbol: %s has bad section index %d.\n", - name, syms[k].st_shndx); - return NULL; - } - - /* Found the symbol we are looking for */ - return &syms[k]; - } - } - - return NULL; -} - void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) { struct purgatory_info *pi = &image->purgatory_info; -- 2.34.1

2 1

[PATCH OLK-6.6] ext4: fix iloc.bh leak in ext4_xattr_inode_update_ref
by Yongjian Sun 06 Mar '26

06 Mar '26

From: Yang Erkun <yangerkun(a)huawei.com> mainline inclusion from mainline-v6.19-rc6 commit d250bdf531d9cd4096fedbb9f172bb2ca660c868 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13696 CVE: CVE-2026-23145 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- The error branch for ext4_xattr_inode_update_ref forget to release the refcount for iloc.bh. Find this when review code. Fixes: 57295e835408 ("ext4: guard against EA inode refcount underflow in xattr update") Signed-off-by: Yang Erkun <yangerkun(a)huawei.com> Reviewed-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Zhang Yi <yi.zhang(a)huawei.com> Link: https://patch.msgid.link/20251213055706.3417529-1-yangerkun@huawei.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Cc: stable(a)kernel.org Signed-off-by: Yongjian Sun <sunyongjian1(a)huawei.com> --- fs/ext4/xattr.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index cd906aa08afa..96810af688f5 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1047,6 +1047,7 @@ static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode, ext4_error_inode(ea_inode, __func__, __LINE__, 0, "EA inode %lu ref wraparound: ref_count=%lld ref_change=%d", ea_inode->i_ino, ref_count, ref_change); + brelse(iloc.bh); ret = -EFSCORRUPTED; goto out; } -- 2.39.2

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[PATCH OLK-6.6] bus: fsl-mc: fix use-after-free in driver_override_show()
by Lin Ruifeng 06 Mar '26

06 Mar '26

From: Gui-Dong Han <hanguidong02(a)gmail.com> stable inclusion from stable-v6.18.11 commit 1d6bd6183e723a7b256ff34bbb5b498b5f4f2ec0 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13796 CVE: CVE-2026-23221 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 148891e95014b5dc5878acefa57f1940c281c431 upstream. The driver_override_show() function reads the driver_override string without holding the device_lock. However, driver_override_store() uses driver_set_override(), which modifies and frees the string while holding the device_lock. This can result in a concurrent use-after-free if the string is freed by the store function while being read by the show function. Fix this by holding the device_lock around the read operation. Fixes: 1f86a00c1159 ("bus/fsl-mc: add support for 'driver_override' in the mc-bus") Cc: stable(a)vger.kernel.org Signed-off-by: Gui-Dong Han <hanguidong02(a)gmail.com> Reviewed-by: Ioana Ciornei <ioana.ciornei(a)nxp.com> Link: https://lore.kernel.org/r/20251202174438.12658-1-hanguidong02@gmail.com Signed-off-by: Christophe Leroy (CS GROUP) <chleroy(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Conflicts: drivers/bus/fsl-mc/fsl-mc-bus.c [Context Conflicts] Signed-off-by: Lin Ruifeng <linruifeng4(a)huawei.com> --- drivers/bus/fsl-mc/fsl-mc-bus.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c index 350e7b24ee2b..4291b286ec90 100644 --- a/drivers/bus/fsl-mc/fsl-mc-bus.c +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c @@ -201,8 +201,12 @@ static ssize_t driver_override_show(struct device *dev, struct device_attribute *attr, char *buf) { struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev); + ssize_t len; - return snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override); + device_lock(dev); + len = snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override); + device_unlock(dev); + return len; } static DEVICE_ATTR_RW(driver_override); -- 2.43.0

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[PATCH OLK-6.6] ALSA: aloop: Fix racy access at PCM trigger
by Lin Ruifeng 06 Mar '26

06 Mar '26

From: Takashi Iwai <tiwai(a)suse.de> stable inclusion from stable-v6.12.70 commit bad15420050db1803767e58756114800cce91ea4 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13748 CVE: CVE-2026-23191 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 826af7fa62e347464b1b4e0ba2fe19a92438084f upstream. The PCM trigger callback of aloop driver tries to check the PCM state and stop the stream of the tied substream in the corresponding cable. Since both check and stop operations are performed outside the cable lock, this may result in UAF when a program attempts to trigger frequently while opening/closing the tied stream, as spotted by fuzzers. For addressing the UAF, this patch changes two things: - It covers the most of code in loopback_check_format() with cable->lock spinlock, and add the proper NULL checks. This avoids already some racy accesses. - In addition, now we try to check the state of the capture PCM stream that may be stopped in this function, which was the major pain point leading to UAF. Reported-by: syzbot+5f8f3acdee1ec7a7ef7b(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/69783ba1.050a0220.c9109.0011.GAE@google.com Cc: <stable(a)vger.kernel.org> Link: https://patch.msgid.link/20260203141003.116584-1-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Conflicts: sound/drivers/aloop.c [Context Conflicts] Signed-off-by: Lin Ruifeng <linruifeng4(a)huawei.com> --- sound/drivers/aloop.c | 58 +++++++++++++++++++++++++------------------ 1 file changed, 34 insertions(+), 24 deletions(-) diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c index a38e602b4fc6..8a8f416567e4 100644 --- a/sound/drivers/aloop.c +++ b/sound/drivers/aloop.c @@ -319,35 +319,41 @@ static int loopback_snd_timer_close_cable(struct loopback_pcm *dpcm) static int loopback_check_format(struct loopback_cable *cable, int stream) { + struct loopback_pcm *dpcm_play, *dpcm_capt; struct snd_pcm_runtime *runtime, *cruntime; struct loopback_setup *setup; struct snd_card *card; + bool stop_capture = false; int check; - if (cable->valid != CABLE_VALID_BOTH) { - if (stream == SNDRV_PCM_STREAM_PLAYBACK) - goto __notify; - return 0; - } - runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> - substream->runtime; - cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> - substream->runtime; - check = runtime->format != cruntime->format || - runtime->rate != cruntime->rate || - runtime->channels != cruntime->channels; - if (!check) - return 0; - if (stream == SNDRV_PCM_STREAM_CAPTURE) { - return -EIO; - } else { - snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> - substream, SNDRV_PCM_STATE_DRAINING); - __notify: - runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> - substream->runtime; - setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]); - card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card; + scoped_guard(spinlock_irqsave, &cable->lock) { + dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; + dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE]; + + if (cable->valid != CABLE_VALID_BOTH) { + if (stream == SNDRV_PCM_STREAM_CAPTURE || !dpcm_play) + return 0; + } else { + if (!dpcm_play || !dpcm_capt) + return -EIO; + runtime = dpcm_play->substream->runtime; + cruntime = dpcm_capt->substream->runtime; + if (!runtime || !cruntime) + return -EIO; + check = runtime->format != cruntime->format || + runtime->rate != cruntime->rate || + runtime->channels != cruntime->channels; + if (!check) + return 0; + if (stream == SNDRV_PCM_STREAM_CAPTURE) + return -EIO; + else if (cruntime->state == SNDRV_PCM_STATE_RUNNING) + stop_capture = true; + } + + setup = get_setup(dpcm_play); + card = dpcm_play->loopback->card; + runtime = dpcm_play->substream->runtime; if (setup->format != runtime->format) { snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &setup->format_id); @@ -364,6 +370,10 @@ static int loopback_check_format(struct loopback_cable *cable, int stream) setup->channels = runtime->channels; } } + + if (stop_capture) + snd_pcm_stop(dpcm_capt->substream, SNDRV_PCM_STATE_DRAINING); + return 0; } -- 2.43.0

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[PATCH OLK-6.6 0/3] *** fix CVE-2026-23208 ***
by Lin Ruifeng 06 Mar '26

06 Mar '26

*** fix CVE-2026-23208 *** Breno Leitao (2): spi: tegra210-quad: Move curr_xfer read inside spinlock spi: tegra210-quad: Protect curr_xfer check in IRQ handler Vishwaroop A (1): spi: tegra210-quad: Fix timeout handling drivers/spi/spi-tegra210-quad.c | 49 ++++++++++++++++++++++++++++++--- 1 file changed, 45 insertions(+), 4 deletions(-) -- 2.43.0

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[PATCH OLK-6.6 0/2] *** fix CVE-2026-23208 ***
by Lin Ruifeng 06 Mar '26

06 Mar '26

*** fix CVE-2026-23208 *** Edward Adam Davis (1): ALSA: usb-audio: Prevent excessive number of frames Takashi Iwai (1): ALSA: usb-audio: Use the right limit for PCM OOB check sound/usb/pcm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) -- 2.43.0

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[PATCH OLK-6.6] of: unittest: Fix memory leak in unittest_data_add()
by Lin Ruifeng 06 Mar '26

06 Mar '26

From: Zilin Guan <zilin(a)seu.edu.cn> stable inclusion from stable-v6.18.6 commit f09b0f705bd7197863b90256ef533a6414d1db2c category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13687 CVE: CVE-2026-23137 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 235a1eb8d2dcc49a6cf0a5ee1aa85544a5d0054b ] In unittest_data_add(), if of_resolve_phandles() fails, the allocated unittest_data is not freed, leading to a memory leak. Fix this by using scope-based cleanup helper __free(kfree) for automatic resource cleanup. This ensures unittest_data is automatically freed when it goes out of scope in error paths. For the success path, use retain_and_null_ptr() to transfer ownership of the memory to the device tree and prevent double freeing. Fixes: 2eb46da2a760 ("of/selftest: Use the resolver to fixup phandles") Suggested-by: Rob Herring <robh(a)kernel.org> Co-developed-by: Jianhao Xu <jianhao.xu(a)seu.edu.cn> Signed-off-by: Jianhao Xu <jianhao.xu(a)seu.edu.cn> Signed-off-by: Zilin Guan <zilin(a)seu.edu.cn> Link: https://patch.msgid.link/20251231114915.234638-1-zilin@seu.edu.cn Signed-off-by: Rob Herring (Arm) <robh(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Conflicts: drivers/of/unittest.c [092d00ead733 ("cleanup: Provide retain_and_null_ptr()") was not merged] Signed-off-by: Lin Ruifeng <linruifeng4(a)huawei.com> --- drivers/of/unittest.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c index 5bfec440b4fd..4824dd78e0fd 100644 --- a/drivers/of/unittest.c +++ b/drivers/of/unittest.c @@ -1680,6 +1680,7 @@ static int __init unittest_data_add(void) rc = of_resolve_phandles(unittest_data_node); if (rc) { pr_err("%s: Failed to resolve phandles (rc=%i)\n", __func__, rc); + kfree(unittest_data); of_overlay_mutex_unlock(); return -EINVAL; } -- 2.43.0

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