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FAILED: patch "[PATCH] mptcp: fix ack generation for fallback msk" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

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 5e15395f6d9ec07395866c5511f4b4ac566c0c9b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112448-naming-survey-424d@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 5e15395f6d9ec07395866c5511f4b4ac566c0c9b Mon Sep 17 00:00:00 2001 From: Paolo Abeni <pabeni(a)redhat.com> Date: Tue, 18 Nov 2025 08:20:19 +0100 Subject: [PATCH] mptcp: fix ack generation for fallback msk mptcp_cleanup_rbuf() needs to know the last most recent, mptcp-level rcv_wnd sent, and such information is tracked into the msk->old_wspace field, updated at ack transmission time by mptcp_write_options(). Fallback socket do not add any mptcp options, such helper is never invoked, and msk->old_wspace value remain stale. That in turn makes ack generation at recvmsg() time quite random. Address the issue ensuring mptcp_write_options() is invoked even for fallback sockets, and just update the needed info in such a case. The issue went unnoticed for a long time, as mptcp currently overshots the fallback socket receive buffer autotune significantly. It is going to change in the near future. Fixes: e3859603ba13 ("mptcp: better msk receive window updates") Cc: stable(a)vger.kernel.org Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/594 Signed-off-by: Paolo Abeni <pabeni(a)redhat.com> Reviewed-by: Geliang Tang <geliang(a)kernel.org> Reviewed-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-1-806d37… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 1103b3341a70..8a63bd00807d 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -838,8 +838,11 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, opts->suboptions = 0; + /* Force later mptcp_write_options(), but do not use any actual + * option space. + */ if (unlikely(__mptcp_check_fallback(msk) && !mptcp_check_infinite_map(skb))) - return false; + return true; if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) { if (mptcp_established_options_fastclose(sk, &opt_size, remaining, opts) || @@ -1319,6 +1322,20 @@ static void mptcp_set_rwin(struct tcp_sock *tp, struct tcphdr *th) WRITE_ONCE(msk->old_wspace, tp->rcv_wnd); } +static void mptcp_track_rwin(struct tcp_sock *tp) +{ + const struct sock *ssk = (const struct sock *)tp; + struct mptcp_subflow_context *subflow; + struct mptcp_sock *msk; + + if (!ssk) + return; + + subflow = mptcp_subflow_ctx(ssk); + msk = mptcp_sk(subflow->conn); + WRITE_ONCE(msk->old_wspace, tp->rcv_wnd); +} + __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum) { struct csum_pseudo_header header; @@ -1611,6 +1628,10 @@ void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp, opts->reset_transient, opts->reset_reason); return; + } else if (unlikely(!opts->suboptions)) { + /* Fallback to TCP */ + mptcp_track_rwin(tp); + return; } if (OPTION_MPTCP_PRIO & opts->suboptions) {

3 days, 12 hours

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FAILED: patch "[PATCH] mptcp: fix a race in mptcp_pm_del_add_timer()" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

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 426358d9be7ce3518966422f87b96f1bad27295f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112431-pentagon-posture-3ba1@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 426358d9be7ce3518966422f87b96f1bad27295f Mon Sep 17 00:00:00 2001 From: Eric Dumazet <edumazet(a)google.com> Date: Mon, 17 Nov 2025 10:07:44 +0000 Subject: [PATCH] mptcp: fix a race in mptcp_pm_del_add_timer() mptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry->add_timer) while another might have free entry already, as reported by syzbot. Add RCU protection to fix this issue. Also change confusing add_timer variable with stop_timer boolean. syzbot report: BUG: KASAN: slab-use-after-free in __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616 Read of size 4 at addr ffff8880311e4150 by task kworker/1:1/44 CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events mptcp_worker Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616 sk_stop_timer_sync+0x1b/0x90 net/core/sock.c:3631 mptcp_pm_del_add_timer+0x283/0x310 net/mptcp/pm.c:362 mptcp_incoming_options+0x1357/0x1f60 net/mptcp/options.c:1174 tcp_data_queue+0xca/0x6450 net/ipv4/tcp_input.c:5361 tcp_rcv_established+0x1335/0x2670 net/ipv4/tcp_input.c:6441 tcp_v4_do_rcv+0x98b/0xbf0 net/ipv4/tcp_ipv4.c:1931 tcp_v4_rcv+0x252a/0x2dc0 net/ipv4/tcp_ipv4.c:2374 ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:239 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6079 [inline] __netif_receive_skb+0x143/0x380 net/core/dev.c:6192 process_backlog+0x31e/0x900 net/core/dev.c:6544 __napi_poll+0xb6/0x540 net/core/dev.c:7594 napi_poll net/core/dev.c:7657 [inline] net_rx_action+0x5f7/0xda0 net/core/dev.c:7784 handle_softirqs+0x22f/0x710 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] __local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302 mptcp_pm_send_ack net/mptcp/pm.c:210 [inline] mptcp_pm_addr_send_ack+0x41f/0x500 net/mptcp/pm.c:-1 mptcp_pm_worker+0x174/0x320 net/mptcp/pm.c:1002 mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> Allocated by task 44: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x1ef/0x6c0 mm/slub.c:5748 kmalloc_noprof include/linux/slab.h:957 [inline] mptcp_pm_alloc_anno_list+0x104/0x460 net/mptcp/pm.c:385 mptcp_pm_create_subflow_or_signal_addr+0xf9d/0x1360 net/mptcp/pm_kernel.c:355 mptcp_pm_nl_fully_established net/mptcp/pm_kernel.c:409 [inline] __mptcp_pm_kernel_worker+0x417/0x1ef0 net/mptcp/pm_kernel.c:1529 mptcp_pm_worker+0x1ee/0x320 net/mptcp/pm.c:1008 mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 6630: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2523 [inline] slab_free mm/slub.c:6611 [inline] kfree+0x197/0x950 mm/slub.c:6818 mptcp_remove_anno_list_by_saddr+0x2d/0x40 net/mptcp/pm.c:158 mptcp_pm_flush_addrs_and_subflows net/mptcp/pm_kernel.c:1209 [inline] mptcp_nl_flush_addrs_list net/mptcp/pm_kernel.c:1240 [inline] mptcp_pm_nl_flush_addrs_doit+0x593/0xbb0 net/mptcp/pm_kernel.c:1281 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x846/0xa10 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x508/0x820 net/socket.c:2630 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0x1a1/0x260 net/socket.c:2719 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Cc: stable(a)vger.kernel.org Fixes: 00cfd77b9063 ("mptcp: retransmit ADD_ADDR when timeout") Reported-by: syzbot+2a6fbf0f0530375968df(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/691ad3c3.a70a0220.f6df1.0004.GAE@google.com Signed-off-by: Eric Dumazet <edumazet(a)google.com> Cc: Geliang Tang <geliang(a)kernel.org> Reviewed-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> Link: https://patch.msgid.link/20251117100745.1913963-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c index 2ff1b9499568..9604b91902b8 100644 --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -18,6 +18,7 @@ struct mptcp_pm_add_entry { u8 retrans_times; struct timer_list add_timer; struct mptcp_sock *sock; + struct rcu_head rcu; }; static DEFINE_SPINLOCK(mptcp_pm_list_lock); @@ -155,7 +156,7 @@ bool mptcp_remove_anno_list_by_saddr(struct mptcp_sock *msk, entry = mptcp_pm_del_add_timer(msk, addr, false); ret = entry; - kfree(entry); + kfree_rcu(entry, rcu); return ret; } @@ -345,22 +346,27 @@ mptcp_pm_del_add_timer(struct mptcp_sock *msk, { struct mptcp_pm_add_entry *entry; struct sock *sk = (struct sock *)msk; - struct timer_list *add_timer = NULL; + bool stop_timer = false; + + rcu_read_lock(); spin_lock_bh(&msk->pm.lock); entry = mptcp_lookup_anno_list_by_saddr(msk, addr); if (entry && (!check_id || entry->addr.id == addr->id)) { entry->retrans_times = ADD_ADDR_RETRANS_MAX; - add_timer = &entry->add_timer; + stop_timer = true; } if (!check_id && entry) list_del(&entry->list); spin_unlock_bh(&msk->pm.lock); - /* no lock, because sk_stop_timer_sync() is calling timer_delete_sync() */ - if (add_timer) - sk_stop_timer_sync(sk, add_timer); + /* Note: entry might have been removed by another thread. + * We hold rcu_read_lock() to ensure it is not freed under us. + */ + if (stop_timer) + sk_stop_timer_sync(sk, &entry->add_timer); + rcu_read_unlock(); return entry; } @@ -415,7 +421,7 @@ static void mptcp_pm_free_anno_list(struct mptcp_sock *msk) list_for_each_entry_safe(entry, tmp, &free_list, list) { sk_stop_timer_sync(sk, &entry->add_timer); - kfree(entry); + kfree_rcu(entry, rcu); } }

3 days, 12 hours

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[merged mm-hotfixes-stable] mm-huge_memory-fix-null-pointer-deference-when-splitting-folio.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/huge_memory: fix NULL pointer deference when splitting folio has been removed from the -mm tree. Its filename was mm-huge_memory-fix-null-pointer-deference-when-splitting-folio.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Wei Yang <richard.weiyang(a)gmail.com> Subject: mm/huge_memory: fix NULL pointer deference when splitting folio Date: Wed, 19 Nov 2025 23:53:02 +0000 Commit c010d47f107f ("mm: thp: split huge page to any lower order pages") introduced an early check on the folio's order via mapping->flags before proceeding with the split work. This check introduced a bug: for shmem folios in the swap cache and truncated folios, the mapping pointer can be NULL. Accessing mapping->flags in this state leads directly to a NULL pointer dereference. This commit fixes the issue by moving the check for mapping != NULL before any attempt to access mapping->flags. Link: https://lkml.kernel.org/r/20251119235302.24773-1-richard.weiyang@gmail.com Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages") Signed-off-by: Wei Yang <richard.weiyang(a)gmail.com> Reviewed-by: Zi Yan <ziy(a)nvidia.com> Acked-by: David Hildenbrand (Red Hat) <david(a)kernel.org> Reviewed-by: Baolin Wang <baolin.wang(a)linux.alibaba.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/huge_memory.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-fix-null-pointer-deference-when-splitting-folio +++ a/mm/huge_memory.c @@ -3619,6 +3619,16 @@ static int __folio_split(struct folio *f if (folio != page_folio(split_at) || folio != page_folio(lock_at)) return -EINVAL; + /* + * Folios that just got truncated cannot get split. Signal to the + * caller that there was a race. + * + * TODO: this will also currently refuse shmem folios that are in the + * swapcache. + */ + if (!is_anon && !folio->mapping) + return -EBUSY; + if (new_order >= folio_order(folio)) return -EINVAL; @@ -3659,18 +3669,6 @@ static int __folio_split(struct folio *f gfp_t gfp; mapping = folio->mapping; - - /* Truncated ? */ - /* - * TODO: add support for large shmem folio in swap cache. - * When shmem is in swap cache, mapping is NULL and - * folio_test_swapcache() is true. - */ - if (!mapping) { - ret = -EBUSY; - goto out; - } - min_order = mapping_min_folio_order(folio->mapping); if (new_order < min_order) { ret = -EINVAL; _ Patches currently in -mm which might be from richard.weiyang(a)gmail.com are mm-huge_memory-add-pmd-folio-to-ds_queue-in-do_huge_zero_wp_pmd.patch mm-khugepaged-unify-pmd-folio-installation-with-map_anon_folio_pmd.patch mm-huge_memory-only-get-folio_order-once-during-__folio_split.patch mm-huge_memory-introduce-enum-split_type-for-clarity.patch mm-huge_memory-merge-uniform_split_supported-and-non_uniform_split_supported.patch mm-khugepaged-remove-redundant-clearing-of-struct-collapse_control.patch mm-khugepaged-continue-to-collapse-on-scan_pmd_none.patch mm-khugepaged-unify-scan_pmd_none-and-scan_pmd_null-into-scan_no_pte_table.patch

3 days, 13 hours

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[merged mm-hotfixes-stable] selftests-mm-fix-division-by-zero-in-uffd-unit-tests.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: selftests/mm: fix division-by-zero in uffd-unit-tests has been removed from the -mm tree. Its filename was selftests-mm-fix-division-by-zero-in-uffd-unit-tests.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Carlos Llamas <cmllamas(a)google.com> Subject: selftests/mm: fix division-by-zero in uffd-unit-tests Date: Thu, 13 Nov 2025 03:46:22 +0000 Commit 4dfd4bba8578 ("selftests/mm/uffd: refactor non-composite global vars into struct") moved some of the operations previously implemented in uffd_setup_environment() earlier in the main test loop. The calculation of nr_pages, which involves a division by page_size, now occurs before checking that default_huge_page_size() returns a non-zero This leads to a division-by-zero error on systems with !CONFIG_HUGETLB. Fix this by relocating the non-zero page_size check before the nr_pages calculation, as it was originally implemented. Link: https://lkml.kernel.org/r/20251113034623.3127012-1-cmllamas@google.com Fixes: 4dfd4bba8578 ("selftests/mm/uffd: refactor non-composite global vars into struct") Signed-off-by: Carlos Llamas <cmllamas(a)google.com> Acked-by: David Hildenbrand (Red Hat) <david(a)kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt(a)kernel.org> Reviewed-by: Ujwal Kundur <ujwal.kundur(a)gmail.com> Cc: Brendan Jackman <jackmanb(a)google.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: Michal Hocko <mhocko(a)suse.com> Cc: Peter Xu <peterx(a)redhat.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- tools/testing/selftests/mm/uffd-unit-tests.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) --- a/tools/testing/selftests/mm/uffd-unit-tests.c~selftests-mm-fix-division-by-zero-in-uffd-unit-tests +++ a/tools/testing/selftests/mm/uffd-unit-tests.c @@ -1758,10 +1758,15 @@ int main(int argc, char *argv[]) uffd_test_ops = mem_type->mem_ops; uffd_test_case_ops = test->test_case_ops; - if (mem_type->mem_flag & (MEM_HUGETLB_PRIVATE | MEM_HUGETLB)) + if (mem_type->mem_flag & (MEM_HUGETLB_PRIVATE | MEM_HUGETLB)) { gopts.page_size = default_huge_page_size(); - else + if (gopts.page_size == 0) { + uffd_test_skip("huge page size is 0, feature missing?"); + continue; + } + } else { gopts.page_size = psize(); + } /* Ensure we have at least 2 pages */ gopts.nr_pages = MAX(UFFD_TEST_MEM_SIZE, gopts.page_size * 2) @@ -1776,12 +1781,6 @@ int main(int argc, char *argv[]) continue; uffd_test_start("%s on %s", test->name, mem_type->name); - if ((mem_type->mem_flag == MEM_HUGETLB || - mem_type->mem_flag == MEM_HUGETLB_PRIVATE) && - (default_huge_page_size() == 0)) { - uffd_test_skip("huge page size is 0, feature missing?"); - continue; - } if (!uffd_feature_supported(test)) { uffd_test_skip("feature missing"); continue; _ Patches currently in -mm which might be from cmllamas(a)google.com are

3 days, 13 hours

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[merged mm-hotfixes-stable] mm-memfd-fix-information-leak-in-hugetlb-folios.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/memfd: fix information leak in hugetlb folios has been removed from the -mm tree. Its filename was mm-memfd-fix-information-leak-in-hugetlb-folios.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Deepanshu Kartikey <kartikey406(a)gmail.com> Subject: mm/memfd: fix information leak in hugetlb folios Date: Wed, 12 Nov 2025 20:20:34 +0530 When allocating hugetlb folios for memfd, three initialization steps are missing: 1. Folios are not zeroed, leading to kernel memory disclosure to userspace 2. Folios are not marked uptodate before adding to page cache 3. hugetlb_fault_mutex is not taken before hugetlb_add_to_page_cache() The memfd allocation path bypasses the normal page fault handler (hugetlb_no_page) which would handle all of these initialization steps. This is problematic especially for udmabuf use cases where folios are pinned and directly accessed by userspace via DMA. Fix by matching the initialization pattern used in hugetlb_no_page(): - Zero the folio using folio_zero_user() which is optimized for huge pages - Mark it uptodate with folio_mark_uptodate() - Take hugetlb_fault_mutex before adding to page cache to prevent races The folio_zero_user() change also fixes a potential security issue where uninitialized kernel memory could be disclosed to userspace through read() or mmap() operations on the memfd. Link: https://lkml.kernel.org/r/20251112145034.2320452-1-kartikey406@gmail.com Fixes: 89c1905d9c14 ("mm/gup: introduce memfd_pin_folios() for pinning memfd folios") Signed-off-by: Deepanshu Kartikey <kartikey406(a)gmail.com> Reported-by: syzbot+f64019ba229e3a5c411b(a)syzkaller.appspotmail.com Link: https://lore.kernel.org/all/20251112031631.2315651-1-kartikey406@gmail.com/ [v1] Closes: https://syzkaller.appspot.com/bug?extid=f64019ba229e3a5c411b Suggested-by: Oscar Salvador <osalvador(a)suse.de> Suggested-by: David Hildenbrand <david(a)redhat.com> Tested-by: syzbot+f64019ba229e3a5c411b(a)syzkaller.appspotmail.com Acked-by: Oscar Salvador <osalvador(a)suse.de> Acked-by: David Hildenbrand (Red Hat) <david(a)kernel.org> Acked-by: Hugh Dickins <hughd(a)google.com> Cc: Vivek Kasireddy <vivek.kasireddy(a)intel.com> Cc: Jason Gunthorpe <jgg(a)nvidia.com> Cc: Jason Gunthorpe <jgg(a)nvidia.com> (v2) Cc: Christoph Hellwig <hch(a)lst.de> (v6) Cc: Dave Airlie <airlied(a)redhat.com> Cc: Gerd Hoffmann <kraxel(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/memfd.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) --- a/mm/memfd.c~mm-memfd-fix-information-leak-in-hugetlb-folios +++ a/mm/memfd.c @@ -96,9 +96,36 @@ struct folio *memfd_alloc_folio(struct f NULL, gfp_mask); if (folio) { + u32 hash; + + /* + * Zero the folio to prevent information leaks to userspace. + * Use folio_zero_user() which is optimized for huge/gigantic + * pages. Pass 0 as addr_hint since this is not a faulting path + * and we don't have a user virtual address yet. + */ + folio_zero_user(folio, 0); + + /* + * Mark the folio uptodate before adding to page cache, + * as required by filemap.c and other hugetlb paths. + */ + __folio_mark_uptodate(folio); + + /* + * Serialize hugepage allocation and instantiation to prevent + * races with concurrent allocations, as required by all other + * callers of hugetlb_add_to_page_cache(). + */ + hash = hugetlb_fault_mutex_hash(memfd->f_mapping, idx); + mutex_lock(&hugetlb_fault_mutex_table[hash]); + err = hugetlb_add_to_page_cache(folio, memfd->f_mapping, idx); + + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + if (err) { folio_put(folio); goto err_unresv; _ Patches currently in -mm which might be from kartikey406(a)gmail.com are

3 days, 13 hours

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[merged mm-hotfixes-stable] mm-swap-remove-duplicate-nr_swap_pages-decrement-in-get_swap_page_of_type.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm: swap: remove duplicate nr_swap_pages decrement in get_swap_page_of_type() has been removed from the -mm tree. Its filename was mm-swap-remove-duplicate-nr_swap_pages-decrement-in-get_swap_page_of_type.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Youngjun Park <youngjun.park(a)lge.com> Subject: mm: swap: remove duplicate nr_swap_pages decrement in get_swap_page_of_type() Date: Sun, 2 Nov 2025 17:24:56 +0900 After commit 4f78252da887, nr_swap_pages is decremented in swap_range_alloc(). Since cluster_alloc_swap_entry() calls swap_range_alloc() internally, the decrement in get_swap_page_of_type() causes double-decrementing. As a representative userspace-visible runtime example of the impact, /proc/meminfo reports increasingly inaccurate SwapFree values. The discrepancy grows with each swap allocation, and during hibernation when large amounts of memory are written to swap, the reported value can deviate significantly from actual available swap space, misleading users and monitoring tools. Remove the duplicate decrement. Link: https://lkml.kernel.org/r/20251102082456.79807-1-youngjun.park@lge.com Fixes: 4f78252da887 ("mm: swap: move nr_swap_pages counter decrement from folio_alloc_swap() to swap_range_alloc()") Signed-off-by: Youngjun Park <youngjun.park(a)lge.com> Acked-by: Chris Li <chrisl(a)kernel.org> Reviewed-by: Barry Song <baohua(a)kernel.org> Reviewed-by: Kairui Song <kasong(a)tencent.com> Acked-by: Nhat Pham <nphamcs(a)gmail.com> Cc: Baoquan He <bhe(a)redhat.com> Cc: Kemeng Shi <shikemeng(a)huaweicloud.com> Cc: <stable(a)vger.kernel.org> [6.17+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/swapfile.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/mm/swapfile.c~mm-swap-remove-duplicate-nr_swap_pages-decrement-in-get_swap_page_of_type +++ a/mm/swapfile.c @@ -2005,10 +2005,8 @@ swp_entry_t get_swap_page_of_type(int ty local_lock(&percpu_swap_cluster.lock); offset = cluster_alloc_swap_entry(si, 0, 1); local_unlock(&percpu_swap_cluster.lock); - if (offset) { + if (offset) entry = swp_entry(si->type, offset); - atomic_long_dec(&nr_swap_pages); - } } put_swap_device(si); } _ Patches currently in -mm which might be from youngjun.park(a)lge.com are mm-swap-fix-wrong-plist-empty-check-in-swap_alloc_slow.patch mm-swap-fix-memory-leak-in-setup_clusters-error-path.patch mm-swap-use-swp_solidstate-to-determine-if-swap-is-rotational.patch mm-swap-remove-redundant-comment-for-read_swap_cache_async.patch mm-swap-change-swap_alloc_slow-to-void.patch mm-swap-remove-scan_swap_map_slots-references-from-comments.patch

3 days, 13 hours

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[tip: x86/urgent] x86/CPU/AMD: Add RDSEED fix for Zen5

by tip-bot2 for Gregory Price

The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 607b9fb2ce248cc5b633c5949e0153838992c152 Gitweb: https://git.kernel.org/tip/607b9fb2ce248cc5b633c5949e0153838992c152 Author: Gregory Price <gourry(a)gourry.net> AuthorDate: Mon, 20 Oct 2025 11:13:55 +02:00 Committer: Borislav Petkov (AMD) <bp(a)alien8.de> CommitterDate: Tue, 28 Oct 2025 12:37:49 +01:00 x86/CPU/AMD: Add RDSEED fix for Zen5 There's an issue with RDSEED's 16-bit and 32-bit register output variants on Zen5 which return a random value of 0 "at a rate inconsistent with randomness while incorrectly signaling success (CF=1)". Search the web for AMD-SB-7055 for more detail. Add a fix glue which checks microcode revisions. [ bp: Add microcode revisions checking, rewrite. ] Cc: stable(a)vger.kernel.org Signed-off-by: Gregory Price <gourry(a)gourry.net> Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Link: https://lore.kernel.org/r/20251018024010.4112396-1-gourry@gourry.net --- arch/x86/kernel/cpu/amd.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index ccaa51c..bc29be6 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -1035,8 +1035,18 @@ static void init_amd_zen4(struct cpuinfo_x86 *c) } } +static const struct x86_cpu_id zen5_rdseed_microcode[] = { + ZEN_MODEL_STEP_UCODE(0x1a, 0x02, 0x1, 0x0b00215a), + ZEN_MODEL_STEP_UCODE(0x1a, 0x11, 0x0, 0x0b101054), +}; + static void init_amd_zen5(struct cpuinfo_x86 *c) { + if (!x86_match_min_microcode_rev(zen5_rdseed_microcode)) { + clear_cpu_cap(c, X86_FEATURE_RDSEED); + msr_clear_bit(MSR_AMD64_CPUID_FN_7, 18); + pr_emerg_once("RDSEED32 is broken. Disabling the corresponding CPUID bit.\n"); + } } static void init_amd(struct cpuinfo_x86 *c)

3 days, 13 hours

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FAILED: patch "[PATCH] mm/mempool: fix poisoning order>0 pages with HIGHMEM" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-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-5.4.y git checkout FETCH_HEAD git cherry-pick -x ec33b59542d96830e3c89845ff833cf7b25ef172 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112438-stoppable-bribe-71e6@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ec33b59542d96830e3c89845ff833cf7b25ef172 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka <vbabka(a)suse.cz> Date: Thu, 13 Nov 2025 19:54:35 +0100 Subject: [PATCH] mm/mempool: fix poisoning order>0 pages with HIGHMEM The kernel test has reported: BUG: unable to handle page fault for address: fffba000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page *pde = 03171067 *pte = 00000000 Oops: Oops: 0002 [#1] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: G T 6.18.0-rc2-00031-gec7f31b2a2d3 #1 NONE a1d066dfe789f54bc7645c7989957d2bdee593ca Tainted: [T]=RANDSTRUCT Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 EIP: memset (arch/x86/include/asm/string_32.h:168 arch/x86/lib/memcpy_32.c:17) Code: a5 8b 4d f4 83 e1 03 74 02 f3 a4 83 c4 04 5e 5f 5d 2e e9 73 41 01 00 90 90 90 3e 8d 74 26 00 55 89 e5 57 56 89 c6 89 d0 89 f7 <f3> aa 89 f0 5e 5f 5d 2e e9 53 41 01 00 cc cc cc 55 89 e5 53 57 56 EAX: 0000006b EBX: 00000015 ECX: 001fefff EDX: 0000006b ESI: fffb9000 EDI: fffba000 EBP: c611fbf0 ESP: c611fbe8 DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00010287 CR0: 80050033 CR2: fffba000 CR3: 0316e000 CR4: 00040690 Call Trace: poison_element (mm/mempool.c:83 mm/mempool.c:102) mempool_init_node (mm/mempool.c:142 mm/mempool.c:226) mempool_init_noprof (mm/mempool.c:250 (discriminator 1)) ? mempool_alloc_pages (mm/mempool.c:640) bio_integrity_initfn (block/bio-integrity.c:483 (discriminator 8)) ? mempool_alloc_pages (mm/mempool.c:640) do_one_initcall (init/main.c:1283) Christoph found out this is due to the poisoning code not dealing properly with CONFIG_HIGHMEM because only the first page is mapped but then the whole potentially high-order page is accessed. We could give up on HIGHMEM here, but it's straightforward to fix this with a loop that's mapping, poisoning or checking and unmapping individual pages. Reported-by: kernel test robot <oliver.sang(a)intel.com> Closes: https://lore.kernel.org/oe-lkp/202511111411.9ebfa1ba-lkp@intel.com Analyzed-by: Christoph Hellwig <hch(a)lst.de> Fixes: bdfedb76f4f5 ("mm, mempool: poison elements backed by slab allocator") Cc: stable(a)vger.kernel.org Tested-by: kernel test robot <oliver.sang(a)intel.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Link: https://patch.msgid.link/20251113-mempool-poison-v1-1-233b3ef984c3@suse.cz Signed-off-by: Vlastimil Babka <vbabka(a)suse.cz> diff --git a/mm/mempool.c b/mm/mempool.c index 1c38e873e546..d7bbf1189db9 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -68,10 +68,20 @@ static void check_element(mempool_t *pool, void *element) } else if (pool->free == mempool_free_pages) { /* Mempools backed by page allocator */ int order = (int)(long)pool->pool_data; - void *addr = kmap_local_page((struct page *)element); - __check_element(pool, addr, 1UL << (PAGE_SHIFT + order)); - kunmap_local(addr); +#ifdef CONFIG_HIGHMEM + for (int i = 0; i < (1 << order); i++) { + struct page *page = (struct page *)element; + void *addr = kmap_local_page(page + i); + + __check_element(pool, addr, PAGE_SIZE); + kunmap_local(addr); + } +#else + void *addr = page_address((struct page *)element); + + __check_element(pool, addr, PAGE_SIZE << order); +#endif } } @@ -97,10 +107,20 @@ static void poison_element(mempool_t *pool, void *element) } else if (pool->alloc == mempool_alloc_pages) { /* Mempools backed by page allocator */ int order = (int)(long)pool->pool_data; - void *addr = kmap_local_page((struct page *)element); - __poison_element(addr, 1UL << (PAGE_SHIFT + order)); - kunmap_local(addr); +#ifdef CONFIG_HIGHMEM + for (int i = 0; i < (1 << order); i++) { + struct page *page = (struct page *)element; + void *addr = kmap_local_page(page + i); + + __poison_element(addr, PAGE_SIZE); + kunmap_local(addr); + } +#else + void *addr = page_address((struct page *)element); + + __poison_element(addr, PAGE_SIZE << order); +#endif } } #else /* CONFIG_SLUB_DEBUG_ON */

3 days, 13 hours

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FAILED: patch "[PATCH] mm/mempool: fix poisoning order>0 pages with HIGHMEM" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-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-5.10.y git checkout FETCH_HEAD git cherry-pick -x ec33b59542d96830e3c89845ff833cf7b25ef172 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112437-sandpaper-almighty-8e37@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ec33b59542d96830e3c89845ff833cf7b25ef172 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka <vbabka(a)suse.cz> Date: Thu, 13 Nov 2025 19:54:35 +0100 Subject: [PATCH] mm/mempool: fix poisoning order>0 pages with HIGHMEM The kernel test has reported: BUG: unable to handle page fault for address: fffba000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page *pde = 03171067 *pte = 00000000 Oops: Oops: 0002 [#1] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: G T 6.18.0-rc2-00031-gec7f31b2a2d3 #1 NONE a1d066dfe789f54bc7645c7989957d2bdee593ca Tainted: [T]=RANDSTRUCT Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 EIP: memset (arch/x86/include/asm/string_32.h:168 arch/x86/lib/memcpy_32.c:17) Code: a5 8b 4d f4 83 e1 03 74 02 f3 a4 83 c4 04 5e 5f 5d 2e e9 73 41 01 00 90 90 90 3e 8d 74 26 00 55 89 e5 57 56 89 c6 89 d0 89 f7 <f3> aa 89 f0 5e 5f 5d 2e e9 53 41 01 00 cc cc cc 55 89 e5 53 57 56 EAX: 0000006b EBX: 00000015 ECX: 001fefff EDX: 0000006b ESI: fffb9000 EDI: fffba000 EBP: c611fbf0 ESP: c611fbe8 DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00010287 CR0: 80050033 CR2: fffba000 CR3: 0316e000 CR4: 00040690 Call Trace: poison_element (mm/mempool.c:83 mm/mempool.c:102) mempool_init_node (mm/mempool.c:142 mm/mempool.c:226) mempool_init_noprof (mm/mempool.c:250 (discriminator 1)) ? mempool_alloc_pages (mm/mempool.c:640) bio_integrity_initfn (block/bio-integrity.c:483 (discriminator 8)) ? mempool_alloc_pages (mm/mempool.c:640) do_one_initcall (init/main.c:1283) Christoph found out this is due to the poisoning code not dealing properly with CONFIG_HIGHMEM because only the first page is mapped but then the whole potentially high-order page is accessed. We could give up on HIGHMEM here, but it's straightforward to fix this with a loop that's mapping, poisoning or checking and unmapping individual pages. Reported-by: kernel test robot <oliver.sang(a)intel.com> Closes: https://lore.kernel.org/oe-lkp/202511111411.9ebfa1ba-lkp@intel.com Analyzed-by: Christoph Hellwig <hch(a)lst.de> Fixes: bdfedb76f4f5 ("mm, mempool: poison elements backed by slab allocator") Cc: stable(a)vger.kernel.org Tested-by: kernel test robot <oliver.sang(a)intel.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Link: https://patch.msgid.link/20251113-mempool-poison-v1-1-233b3ef984c3@suse.cz Signed-off-by: Vlastimil Babka <vbabka(a)suse.cz> diff --git a/mm/mempool.c b/mm/mempool.c index 1c38e873e546..d7bbf1189db9 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -68,10 +68,20 @@ static void check_element(mempool_t *pool, void *element) } else if (pool->free == mempool_free_pages) { /* Mempools backed by page allocator */ int order = (int)(long)pool->pool_data; - void *addr = kmap_local_page((struct page *)element); - __check_element(pool, addr, 1UL << (PAGE_SHIFT + order)); - kunmap_local(addr); +#ifdef CONFIG_HIGHMEM + for (int i = 0; i < (1 << order); i++) { + struct page *page = (struct page *)element; + void *addr = kmap_local_page(page + i); + + __check_element(pool, addr, PAGE_SIZE); + kunmap_local(addr); + } +#else + void *addr = page_address((struct page *)element); + + __check_element(pool, addr, PAGE_SIZE << order); +#endif } } @@ -97,10 +107,20 @@ static void poison_element(mempool_t *pool, void *element) } else if (pool->alloc == mempool_alloc_pages) { /* Mempools backed by page allocator */ int order = (int)(long)pool->pool_data; - void *addr = kmap_local_page((struct page *)element); - __poison_element(addr, 1UL << (PAGE_SHIFT + order)); - kunmap_local(addr); +#ifdef CONFIG_HIGHMEM + for (int i = 0; i < (1 << order); i++) { + struct page *page = (struct page *)element; + void *addr = kmap_local_page(page + i); + + __poison_element(addr, PAGE_SIZE); + kunmap_local(addr); + } +#else + void *addr = page_address((struct page *)element); + + __poison_element(addr, PAGE_SIZE << order); +#endif } } #else /* CONFIG_SLUB_DEBUG_ON */

3 days, 13 hours

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FAILED: patch "[PATCH] mm/mempool: fix poisoning order>0 pages with HIGHMEM" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

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 ec33b59542d96830e3c89845ff833cf7b25ef172 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112436-unabashed-tacky-b8b3@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ec33b59542d96830e3c89845ff833cf7b25ef172 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka <vbabka(a)suse.cz> Date: Thu, 13 Nov 2025 19:54:35 +0100 Subject: [PATCH] mm/mempool: fix poisoning order>0 pages with HIGHMEM The kernel test has reported: BUG: unable to handle page fault for address: fffba000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page *pde = 03171067 *pte = 00000000 Oops: Oops: 0002 [#1] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: G T 6.18.0-rc2-00031-gec7f31b2a2d3 #1 NONE a1d066dfe789f54bc7645c7989957d2bdee593ca Tainted: [T]=RANDSTRUCT Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 EIP: memset (arch/x86/include/asm/string_32.h:168 arch/x86/lib/memcpy_32.c:17) Code: a5 8b 4d f4 83 e1 03 74 02 f3 a4 83 c4 04 5e 5f 5d 2e e9 73 41 01 00 90 90 90 3e 8d 74 26 00 55 89 e5 57 56 89 c6 89 d0 89 f7 <f3> aa 89 f0 5e 5f 5d 2e e9 53 41 01 00 cc cc cc 55 89 e5 53 57 56 EAX: 0000006b EBX: 00000015 ECX: 001fefff EDX: 0000006b ESI: fffb9000 EDI: fffba000 EBP: c611fbf0 ESP: c611fbe8 DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00010287 CR0: 80050033 CR2: fffba000 CR3: 0316e000 CR4: 00040690 Call Trace: poison_element (mm/mempool.c:83 mm/mempool.c:102) mempool_init_node (mm/mempool.c:142 mm/mempool.c:226) mempool_init_noprof (mm/mempool.c:250 (discriminator 1)) ? mempool_alloc_pages (mm/mempool.c:640) bio_integrity_initfn (block/bio-integrity.c:483 (discriminator 8)) ? mempool_alloc_pages (mm/mempool.c:640) do_one_initcall (init/main.c:1283) Christoph found out this is due to the poisoning code not dealing properly with CONFIG_HIGHMEM because only the first page is mapped but then the whole potentially high-order page is accessed. We could give up on HIGHMEM here, but it's straightforward to fix this with a loop that's mapping, poisoning or checking and unmapping individual pages. Reported-by: kernel test robot <oliver.sang(a)intel.com> Closes: https://lore.kernel.org/oe-lkp/202511111411.9ebfa1ba-lkp@intel.com Analyzed-by: Christoph Hellwig <hch(a)lst.de> Fixes: bdfedb76f4f5 ("mm, mempool: poison elements backed by slab allocator") Cc: stable(a)vger.kernel.org Tested-by: kernel test robot <oliver.sang(a)intel.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Link: https://patch.msgid.link/20251113-mempool-poison-v1-1-233b3ef984c3@suse.cz Signed-off-by: Vlastimil Babka <vbabka(a)suse.cz> diff --git a/mm/mempool.c b/mm/mempool.c index 1c38e873e546..d7bbf1189db9 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -68,10 +68,20 @@ static void check_element(mempool_t *pool, void *element) } else if (pool->free == mempool_free_pages) { /* Mempools backed by page allocator */ int order = (int)(long)pool->pool_data; - void *addr = kmap_local_page((struct page *)element); - __check_element(pool, addr, 1UL << (PAGE_SHIFT + order)); - kunmap_local(addr); +#ifdef CONFIG_HIGHMEM + for (int i = 0; i < (1 << order); i++) { + struct page *page = (struct page *)element; + void *addr = kmap_local_page(page + i); + + __check_element(pool, addr, PAGE_SIZE); + kunmap_local(addr); + } +#else + void *addr = page_address((struct page *)element); + + __check_element(pool, addr, PAGE_SIZE << order); +#endif } } @@ -97,10 +107,20 @@ static void poison_element(mempool_t *pool, void *element) } else if (pool->alloc == mempool_alloc_pages) { /* Mempools backed by page allocator */ int order = (int)(long)pool->pool_data; - void *addr = kmap_local_page((struct page *)element); - __poison_element(addr, 1UL << (PAGE_SHIFT + order)); - kunmap_local(addr); +#ifdef CONFIG_HIGHMEM + for (int i = 0; i < (1 << order); i++) { + struct page *page = (struct page *)element; + void *addr = kmap_local_page(page + i); + + __poison_element(addr, PAGE_SIZE); + kunmap_local(addr); + } +#else + void *addr = page_address((struct page *)element); + + __poison_element(addr, PAGE_SIZE << order); +#endif } } #else /* CONFIG_SLUB_DEBUG_ON */

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