- Linux-stable-mirror - lists.linaro.org

[merged mm-hotfixes-stable] tools-testing-selftests-fix-guard-region-test-tmpfs-assumption.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: tools/testing/selftests: fix guard region test tmpfs assumption has been removed from the -mm tree. Its filename was tools-testing-selftests-fix-guard-region-test-tmpfs-assumption.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: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Subject: tools/testing/selftests: fix guard region test tmpfs assumption Date: Fri, 25 Apr 2025 17:24:36 +0100 The current implementation of the guard region tests assume that /tmp is mounted as tmpfs, that is shmem. This isn't always the case, and at least one instance of a spurious test failure has been reported as a result. This assumption is unsafe, rushed and silly - and easily remedied by simply using memfd, so do so. We also have to fixup the readonly_file test to explicitly only be applicable to file-backed cases. Link: https://lkml.kernel.org/r/20250425162436.564002-1-lorenzo.stoakes@oracle.com Fixes: 272f37d3e99a ("tools/selftests: expand all guard region tests to file-backed") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Ryan Roberts <ryan.roberts(a)arm.com> Closes: https://lore.kernel.org/linux-mm/a2d2766b-0ab4-437b-951a-8595a7506fe9@arm.c… Reviewed-by: Ryan Roberts <ryan.roberts(a)arm.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- tools/testing/selftests/mm/guard-regions.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) --- a/tools/testing/selftests/mm/guard-regions.c~tools-testing-selftests-fix-guard-region-test-tmpfs-assumption +++ a/tools/testing/selftests/mm/guard-regions.c @@ -271,12 +271,16 @@ FIXTURE_SETUP(guard_regions) self->page_size = (unsigned long)sysconf(_SC_PAGESIZE); setup_sighandler(); - if (variant->backing == ANON_BACKED) + switch (variant->backing) { + case ANON_BACKED: return; - - self->fd = open_file( - variant->backing == SHMEM_BACKED ? "/tmp/" : "", - self->path); + case LOCAL_FILE_BACKED: + self->fd = open_file("", self->path); + break; + case SHMEM_BACKED: + self->fd = memfd_create(self->path, 0); + break; + } /* We truncate file to at least 100 pages, tests can modify as needed. */ ASSERT_EQ(ftruncate(self->fd, 100 * self->page_size), 0); @@ -1696,7 +1700,7 @@ TEST_F(guard_regions, readonly_file) char *ptr; int i; - if (variant->backing == ANON_BACKED) + if (variant->backing != LOCAL_FILE_BACKED) SKIP(return, "Read-only test specific to file-backed"); /* Map shared so we can populate with pattern, populate it, unmap. */ _ Patches currently in -mm which might be from lorenzo.stoakes(a)oracle.com are maintainers-add-mm-gup-section.patch mm-vma-fix-incorrectly-disallowed-anonymous-vma-merges.patch tools-testing-add-procmap_query-helper-functions-in-mm-self-tests.patch tools-testing-selftests-assert-that-anon-merge-cases-behave-as-expected.patch mm-move-mmap-vma-locking-logic-into-specific-files.patch mm-establish-mm-vma_execc-for-shared-exec-mm-vma-functionality.patch mm-abstract-initial-stack-setup-to-mm-subsystem.patch mm-move-dup_mmap-to-mm.patch mm-perform-vma-allocation-freeing-duplication-in-mm.patch mm-introduce-new-mmap_prepare-file-callback.patch mm-secretmem-convert-to-mmap_prepare-hook.patch mm-vma-remove-mmap-retry-merge.patch

4 months, 1 week

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[merged mm-hotfixes-stable] ocfs2-stop-quota-recovery-before-disabling-quotas.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: ocfs2: stop quota recovery before disabling quotas has been removed from the -mm tree. Its filename was ocfs2-stop-quota-recovery-before-disabling-quotas.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: Jan Kara <jack(a)suse.cz> Subject: ocfs2: stop quota recovery before disabling quotas Date: Thu, 24 Apr 2025 15:45:13 +0200 Currently quota recovery is synchronized with unmount using sb->s_umount semaphore. That is however prone to deadlocks because flush_workqueue(osb->ocfs2_wq) called from umount code can wait for quota recovery to complete while ocfs2_finish_quota_recovery() waits for sb->s_umount semaphore. Grabbing of sb->s_umount semaphore in ocfs2_finish_quota_recovery() is only needed to protect that function from disabling of quotas from ocfs2_dismount_volume(). Handle this problem by disabling quota recovery early during unmount in ocfs2_dismount_volume() instead so that we can drop acquisition of sb->s_umount from ocfs2_finish_quota_recovery(). Link: https://lkml.kernel.org/r/20250424134515.18933-6-jack@suse.cz Fixes: 5f530de63cfc ("ocfs2: Use s_umount for quota recovery protection") Signed-off-by: Jan Kara <jack(a)suse.cz> Reported-by: Shichangkuo <shi.changkuo(a)h3c.com> Reported-by: Murad Masimov <m.masimov(a)mt-integration.ru> Reviewed-by: Heming Zhao <heming.zhao(a)suse.com> Tested-by: Heming Zhao <heming.zhao(a)suse.com> Acked-by: Joseph Qi <joseph.qi(a)linux.alibaba.com> Cc: Changwei Ge <gechangwei(a)live.cn> Cc: Joel Becker <jlbec(a)evilplan.org> Cc: Jun Piao <piaojun(a)huawei.com> Cc: Junxiao Bi <junxiao.bi(a)oracle.com> Cc: Mark Fasheh <mark(a)fasheh.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/ocfs2/journal.c | 20 ++++++++++++++++++-- fs/ocfs2/journal.h | 1 + fs/ocfs2/ocfs2.h | 6 ++++++ fs/ocfs2/quota_local.c | 9 ++------- fs/ocfs2/super.c | 3 +++ 5 files changed, 30 insertions(+), 9 deletions(-) --- a/fs/ocfs2/journal.c~ocfs2-stop-quota-recovery-before-disabling-quotas +++ a/fs/ocfs2/journal.c @@ -225,6 +225,11 @@ out_lock: flush_workqueue(osb->ocfs2_wq); } +void ocfs2_recovery_disable_quota(struct ocfs2_super *osb) +{ + ocfs2_recovery_disable(osb, OCFS2_REC_QUOTA_WANT_DISABLE); +} + void ocfs2_recovery_exit(struct ocfs2_super *osb) { struct ocfs2_recovery_map *rm; @@ -1489,6 +1494,18 @@ static int __ocfs2_recovery_thread(void } } restart: + if (quota_enabled) { + mutex_lock(&osb->recovery_lock); + /* Confirm that recovery thread will no longer recover quotas */ + if (osb->recovery_state == OCFS2_REC_QUOTA_WANT_DISABLE) { + osb->recovery_state = OCFS2_REC_QUOTA_DISABLED; + wake_up(&osb->recovery_event); + } + if (osb->recovery_state >= OCFS2_REC_QUOTA_DISABLED) + quota_enabled = 0; + mutex_unlock(&osb->recovery_lock); + } + status = ocfs2_super_lock(osb, 1); if (status < 0) { mlog_errno(status); @@ -1592,8 +1609,7 @@ bail: mutex_unlock(&osb->recovery_lock); - if (quota_enabled) - kfree(rm_quota); + kfree(rm_quota); return status; } --- a/fs/ocfs2/journal.h~ocfs2-stop-quota-recovery-before-disabling-quotas +++ a/fs/ocfs2/journal.h @@ -148,6 +148,7 @@ void ocfs2_wait_for_recovery(struct ocfs int ocfs2_recovery_init(struct ocfs2_super *osb); void ocfs2_recovery_exit(struct ocfs2_super *osb); +void ocfs2_recovery_disable_quota(struct ocfs2_super *osb); int ocfs2_compute_replay_slots(struct ocfs2_super *osb); void ocfs2_free_replay_slots(struct ocfs2_super *osb); --- a/fs/ocfs2/ocfs2.h~ocfs2-stop-quota-recovery-before-disabling-quotas +++ a/fs/ocfs2/ocfs2.h @@ -310,6 +310,12 @@ void ocfs2_initialize_journal_triggers(s enum ocfs2_recovery_state { OCFS2_REC_ENABLED = 0, + OCFS2_REC_QUOTA_WANT_DISABLE, + /* + * Must be OCFS2_REC_QUOTA_WANT_DISABLE + 1 for + * ocfs2_recovery_disable_quota() to work. + */ + OCFS2_REC_QUOTA_DISABLED, OCFS2_REC_WANT_DISABLE, /* * Must be OCFS2_REC_WANT_DISABLE + 1 for ocfs2_recovery_exit() to work --- a/fs/ocfs2/quota_local.c~ocfs2-stop-quota-recovery-before-disabling-quotas +++ a/fs/ocfs2/quota_local.c @@ -453,8 +453,7 @@ out: /* Sync changes in local quota file into global quota file and * reinitialize local quota file. - * The function expects local quota file to be already locked and - * s_umount locked in shared mode. */ + * The function expects local quota file to be already locked. */ static int ocfs2_recover_local_quota_file(struct inode *lqinode, int type, struct ocfs2_quota_recovery *rec) @@ -588,7 +587,6 @@ int ocfs2_finish_quota_recovery(struct o { unsigned int ino[OCFS2_MAXQUOTAS] = { LOCAL_USER_QUOTA_SYSTEM_INODE, LOCAL_GROUP_QUOTA_SYSTEM_INODE }; - struct super_block *sb = osb->sb; struct ocfs2_local_disk_dqinfo *ldinfo; struct buffer_head *bh; handle_t *handle; @@ -600,7 +598,6 @@ int ocfs2_finish_quota_recovery(struct o printk(KERN_NOTICE "ocfs2: Finishing quota recovery on device (%s) for " "slot %u\n", osb->dev_str, slot_num); - down_read(&sb->s_umount); for (type = 0; type < OCFS2_MAXQUOTAS; type++) { if (list_empty(&(rec->r_list[type]))) continue; @@ -677,7 +674,6 @@ out_put: break; } out: - up_read(&sb->s_umount); kfree(rec); return status; } @@ -843,8 +839,7 @@ static int ocfs2_local_free_info(struct ocfs2_release_local_quota_bitmaps(&oinfo->dqi_chunk); /* - * s_umount held in exclusive mode protects us against racing with - * recovery thread... + * ocfs2_dismount_volume() has already aborted quota recovery... */ if (oinfo->dqi_rec) { ocfs2_free_quota_recovery(oinfo->dqi_rec); --- a/fs/ocfs2/super.c~ocfs2-stop-quota-recovery-before-disabling-quotas +++ a/fs/ocfs2/super.c @@ -1812,6 +1812,9 @@ static void ocfs2_dismount_volume(struct /* Orphan scan should be stopped as early as possible */ ocfs2_orphan_scan_stop(osb); + /* Stop quota recovery so that we can disable quotas */ + ocfs2_recovery_disable_quota(osb); + ocfs2_disable_quotas(osb); /* All dquots should be freed by now */ _ Patches currently in -mm which might be from jack(a)suse.cz are

4 months, 1 week

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[merged mm-hotfixes-stable] ocfs2-implement-handshaking-with-ocfs2-recovery-thread.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: ocfs2: implement handshaking with ocfs2 recovery thread has been removed from the -mm tree. Its filename was ocfs2-implement-handshaking-with-ocfs2-recovery-thread.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: Jan Kara <jack(a)suse.cz> Subject: ocfs2: implement handshaking with ocfs2 recovery thread Date: Thu, 24 Apr 2025 15:45:12 +0200 We will need ocfs2 recovery thread to acknowledge transitions of recovery_state when disabling particular types of recovery. This is similar to what currently happens when disabling recovery completely, just more general. Implement the handshake and use it for exit from recovery. Link: https://lkml.kernel.org/r/20250424134515.18933-5-jack@suse.cz Fixes: 5f530de63cfc ("ocfs2: Use s_umount for quota recovery protection") Signed-off-by: Jan Kara <jack(a)suse.cz> Reviewed-by: Heming Zhao <heming.zhao(a)suse.com> Tested-by: Heming Zhao <heming.zhao(a)suse.com> Acked-by: Joseph Qi <joseph.qi(a)linux.alibaba.com> Cc: Changwei Ge <gechangwei(a)live.cn> Cc: Joel Becker <jlbec(a)evilplan.org> Cc: Jun Piao <piaojun(a)huawei.com> Cc: Junxiao Bi <junxiao.bi(a)oracle.com> Cc: Mark Fasheh <mark(a)fasheh.com> Cc: Murad Masimov <m.masimov(a)mt-integration.ru> Cc: Shichangkuo <shi.changkuo(a)h3c.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/ocfs2/journal.c | 52 ++++++++++++++++++++++++++++--------------- fs/ocfs2/ocfs2.h | 4 +++ 2 files changed, 39 insertions(+), 17 deletions(-) --- a/fs/ocfs2/journal.c~ocfs2-implement-handshaking-with-ocfs2-recovery-thread +++ a/fs/ocfs2/journal.c @@ -190,31 +190,48 @@ int ocfs2_recovery_init(struct ocfs2_sup return 0; } -/* we can't grab the goofy sem lock from inside wait_event, so we use - * memory barriers to make sure that we'll see the null task before - * being woken up */ static int ocfs2_recovery_thread_running(struct ocfs2_super *osb) { - mb(); return osb->recovery_thread_task != NULL; } -void ocfs2_recovery_exit(struct ocfs2_super *osb) +static void ocfs2_recovery_disable(struct ocfs2_super *osb, + enum ocfs2_recovery_state state) { - struct ocfs2_recovery_map *rm; - - /* disable any new recovery threads and wait for any currently - * running ones to exit. Do this before setting the vol_state. */ mutex_lock(&osb->recovery_lock); - osb->recovery_state = OCFS2_REC_DISABLED; + /* + * If recovery thread is not running, we can directly transition to + * final state. + */ + if (!ocfs2_recovery_thread_running(osb)) { + osb->recovery_state = state + 1; + goto out_lock; + } + osb->recovery_state = state; + /* Wait for recovery thread to acknowledge state transition */ + wait_event_cmd(osb->recovery_event, + !ocfs2_recovery_thread_running(osb) || + osb->recovery_state >= state + 1, + mutex_unlock(&osb->recovery_lock), + mutex_lock(&osb->recovery_lock)); +out_lock: mutex_unlock(&osb->recovery_lock); - wait_event(osb->recovery_event, !ocfs2_recovery_thread_running(osb)); - /* At this point, we know that no more recovery threads can be - * launched, so wait for any recovery completion work to - * complete. */ + /* + * At this point we know that no more recovery work can be queued so + * wait for any recovery completion work to complete. + */ if (osb->ocfs2_wq) flush_workqueue(osb->ocfs2_wq); +} + +void ocfs2_recovery_exit(struct ocfs2_super *osb) +{ + struct ocfs2_recovery_map *rm; + + /* disable any new recovery threads and wait for any currently + * running ones to exit. Do this before setting the vol_state. */ + ocfs2_recovery_disable(osb, OCFS2_REC_WANT_DISABLE); /* * Now that recovery is shut down, and the osb is about to be @@ -1569,7 +1586,8 @@ bail: ocfs2_free_replay_slots(osb); osb->recovery_thread_task = NULL; - mb(); /* sync with ocfs2_recovery_thread_running */ + if (osb->recovery_state == OCFS2_REC_WANT_DISABLE) + osb->recovery_state = OCFS2_REC_DISABLED; wake_up(&osb->recovery_event); mutex_unlock(&osb->recovery_lock); @@ -1585,13 +1603,13 @@ void ocfs2_recovery_thread(struct ocfs2_ int was_set = -1; mutex_lock(&osb->recovery_lock); - if (osb->recovery_state < OCFS2_REC_DISABLED) + if (osb->recovery_state < OCFS2_REC_WANT_DISABLE) was_set = ocfs2_recovery_map_set(osb, node_num); trace_ocfs2_recovery_thread(node_num, osb->node_num, osb->recovery_state, osb->recovery_thread_task, was_set); - if (osb->recovery_state == OCFS2_REC_DISABLED) + if (osb->recovery_state >= OCFS2_REC_WANT_DISABLE) goto out; if (osb->recovery_thread_task) --- a/fs/ocfs2/ocfs2.h~ocfs2-implement-handshaking-with-ocfs2-recovery-thread +++ a/fs/ocfs2/ocfs2.h @@ -310,6 +310,10 @@ void ocfs2_initialize_journal_triggers(s enum ocfs2_recovery_state { OCFS2_REC_ENABLED = 0, + OCFS2_REC_WANT_DISABLE, + /* + * Must be OCFS2_REC_WANT_DISABLE + 1 for ocfs2_recovery_exit() to work + */ OCFS2_REC_DISABLED, }; _ Patches currently in -mm which might be from jack(a)suse.cz are

4 months, 1 week

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[merged mm-hotfixes-stable] ocfs2-switch-osb-disable_recovery-to-enum.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: ocfs2: switch osb->disable_recovery to enum has been removed from the -mm tree. Its filename was ocfs2-switch-osb-disable_recovery-to-enum.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: Jan Kara <jack(a)suse.cz> Subject: ocfs2: switch osb->disable_recovery to enum Date: Thu, 24 Apr 2025 15:45:11 +0200 Patch series "ocfs2: Fix deadlocks in quota recovery", v3. This implements another approach to fixing quota recovery deadlocks. We avoid grabbing sb->s_umount semaphore from ocfs2_finish_quota_recovery() and instead stop quota recovery early in ocfs2_dismount_volume(). This patch (of 3): We will need more recovery states than just pure enable / disable to fix deadlocks with quota recovery. Switch osb->disable_recovery to enum. Link: https://lkml.kernel.org/r/20250424134301.1392-1-jack@suse.cz Link: https://lkml.kernel.org/r/20250424134515.18933-4-jack@suse.cz Fixes: 5f530de63cfc ("ocfs2: Use s_umount for quota recovery protection") Signed-off-by: Jan Kara <jack(a)suse.cz> Reviewed-by: Heming Zhao <heming.zhao(a)suse.com> Tested-by: Heming Zhao <heming.zhao(a)suse.com> Acked-by: Joseph Qi <joseph.qi(a)linux.alibaba.com> Cc: Mark Fasheh <mark(a)fasheh.com> Cc: Joel Becker <jlbec(a)evilplan.org> Cc: Junxiao Bi <junxiao.bi(a)oracle.com> Cc: Changwei Ge <gechangwei(a)live.cn> Cc: Jun Piao <piaojun(a)huawei.com> Cc: Murad Masimov <m.masimov(a)mt-integration.ru> Cc: Shichangkuo <shi.changkuo(a)h3c.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/ocfs2/journal.c | 14 ++++++++------ fs/ocfs2/ocfs2.h | 7 ++++++- 2 files changed, 14 insertions(+), 7 deletions(-) --- a/fs/ocfs2/journal.c~ocfs2-switch-osb-disable_recovery-to-enum +++ a/fs/ocfs2/journal.c @@ -174,7 +174,7 @@ int ocfs2_recovery_init(struct ocfs2_sup struct ocfs2_recovery_map *rm; mutex_init(&osb->recovery_lock); - osb->disable_recovery = 0; + osb->recovery_state = OCFS2_REC_ENABLED; osb->recovery_thread_task = NULL; init_waitqueue_head(&osb->recovery_event); @@ -206,7 +206,7 @@ void ocfs2_recovery_exit(struct ocfs2_su /* disable any new recovery threads and wait for any currently * running ones to exit. Do this before setting the vol_state. */ mutex_lock(&osb->recovery_lock); - osb->disable_recovery = 1; + osb->recovery_state = OCFS2_REC_DISABLED; mutex_unlock(&osb->recovery_lock); wait_event(osb->recovery_event, !ocfs2_recovery_thread_running(osb)); @@ -1582,14 +1582,16 @@ bail: void ocfs2_recovery_thread(struct ocfs2_super *osb, int node_num) { + int was_set = -1; + mutex_lock(&osb->recovery_lock); + if (osb->recovery_state < OCFS2_REC_DISABLED) + was_set = ocfs2_recovery_map_set(osb, node_num); trace_ocfs2_recovery_thread(node_num, osb->node_num, - osb->disable_recovery, osb->recovery_thread_task, - osb->disable_recovery ? - -1 : ocfs2_recovery_map_set(osb, node_num)); + osb->recovery_state, osb->recovery_thread_task, was_set); - if (osb->disable_recovery) + if (osb->recovery_state == OCFS2_REC_DISABLED) goto out; if (osb->recovery_thread_task) --- a/fs/ocfs2/ocfs2.h~ocfs2-switch-osb-disable_recovery-to-enum +++ a/fs/ocfs2/ocfs2.h @@ -308,6 +308,11 @@ enum ocfs2_journal_trigger_type { void ocfs2_initialize_journal_triggers(struct super_block *sb, struct ocfs2_triggers triggers[]); +enum ocfs2_recovery_state { + OCFS2_REC_ENABLED = 0, + OCFS2_REC_DISABLED, +}; + struct ocfs2_journal; struct ocfs2_slot_info; struct ocfs2_recovery_map; @@ -370,7 +375,7 @@ struct ocfs2_super struct ocfs2_recovery_map *recovery_map; struct ocfs2_replay_map *replay_map; struct task_struct *recovery_thread_task; - int disable_recovery; + enum ocfs2_recovery_state recovery_state; wait_queue_head_t checkpoint_event; struct ocfs2_journal *journal; unsigned long osb_commit_interval; _ Patches currently in -mm which might be from jack(a)suse.cz are

4 months, 1 week

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[merged mm-hotfixes-stable] mm-userfaultfd-fix-uninitialized-output-field-for-eagain-race.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/userfaultfd: fix uninitialized output field for -EAGAIN race has been removed from the -mm tree. Its filename was mm-userfaultfd-fix-uninitialized-output-field-for-eagain-race.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: Peter Xu <peterx(a)redhat.com> Subject: mm/userfaultfd: fix uninitialized output field for -EAGAIN race Date: Thu, 24 Apr 2025 17:57:28 -0400 While discussing some userfaultfd relevant issues recently, Andrea noticed a potential ABI breakage with -EAGAIN on almost all userfaultfd ioctl()s. Quote from Andrea, explaining how -EAGAIN was processed, and how this should fix it (taking example of UFFDIO_COPY ioctl): The "mmap_changing" and "stale pmd" conditions are already reported as -EAGAIN written in the copy field, this does not change it. This change removes the subnormal case that left copy.copy uninitialized and required apps to explicitly set the copy field to get deterministic behavior (which is a requirement contrary to the documentation in both the manpage and source code). In turn there's no alteration to backwards compatibility as result of this change because userland will find the copy field consistently set to -EAGAIN, and not anymore sometime -EAGAIN and sometime uninitialized. Even then the change only can make a difference to non cooperative users of userfaultfd, so when UFFD_FEATURE_EVENT_* is enabled, which is not true for the vast majority of apps using userfaultfd or this unintended uninitialized field may have been noticed sooner. Meanwhile, since this bug existed for years, it also almost affects all ioctl()s that was introduced later. Besides UFFDIO_ZEROPAGE, these also get affected in the same way: - UFFDIO_CONTINUE - UFFDIO_POISON - UFFDIO_MOVE This patch should have fixed all of them. Link: https://lkml.kernel.org/r/20250424215729.194656-2-peterx@redhat.com Fixes: df2cc96e7701 ("userfaultfd: prevent non-cooperative events vs mcopy_atomic races") Fixes: f619147104c8 ("userfaultfd: add UFFDIO_CONTINUE ioctl") Fixes: fc71884a5f59 ("mm: userfaultfd: add new UFFDIO_POISON ioctl") Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI") Signed-off-by: Peter Xu <peterx(a)redhat.com> Reported-by: Andrea Arcangeli <aarcange(a)redhat.com> Suggested-by: Andrea Arcangeli <aarcange(a)redhat.com> Reviewed-by: David Hildenbrand <david(a)redhat.com> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Axel Rasmussen <axelrasmussen(a)google.com> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/userfaultfd.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) --- a/fs/userfaultfd.c~mm-userfaultfd-fix-uninitialized-output-field-for-eagain-race +++ a/fs/userfaultfd.c @@ -1585,8 +1585,11 @@ static int userfaultfd_copy(struct userf user_uffdio_copy = (struct uffdio_copy __user *) arg; ret = -EAGAIN; - if (atomic_read(&ctx->mmap_changing)) + if (unlikely(atomic_read(&ctx->mmap_changing))) { + if (unlikely(put_user(ret, &user_uffdio_copy->copy))) + return -EFAULT; goto out; + } ret = -EFAULT; if (copy_from_user(&uffdio_copy, user_uffdio_copy, @@ -1641,8 +1644,11 @@ static int userfaultfd_zeropage(struct u user_uffdio_zeropage = (struct uffdio_zeropage __user *) arg; ret = -EAGAIN; - if (atomic_read(&ctx->mmap_changing)) + if (unlikely(atomic_read(&ctx->mmap_changing))) { + if (unlikely(put_user(ret, &user_uffdio_zeropage->zeropage))) + return -EFAULT; goto out; + } ret = -EFAULT; if (copy_from_user(&uffdio_zeropage, user_uffdio_zeropage, @@ -1744,8 +1750,11 @@ static int userfaultfd_continue(struct u user_uffdio_continue = (struct uffdio_continue __user *)arg; ret = -EAGAIN; - if (atomic_read(&ctx->mmap_changing)) + if (unlikely(atomic_read(&ctx->mmap_changing))) { + if (unlikely(put_user(ret, &user_uffdio_continue->mapped))) + return -EFAULT; goto out; + } ret = -EFAULT; if (copy_from_user(&uffdio_continue, user_uffdio_continue, @@ -1801,8 +1810,11 @@ static inline int userfaultfd_poison(str user_uffdio_poison = (struct uffdio_poison __user *)arg; ret = -EAGAIN; - if (atomic_read(&ctx->mmap_changing)) + if (unlikely(atomic_read(&ctx->mmap_changing))) { + if (unlikely(put_user(ret, &user_uffdio_poison->updated))) + return -EFAULT; goto out; + } ret = -EFAULT; if (copy_from_user(&uffdio_poison, user_uffdio_poison, @@ -1870,8 +1882,12 @@ static int userfaultfd_move(struct userf user_uffdio_move = (struct uffdio_move __user *) arg; - if (atomic_read(&ctx->mmap_changing)) - return -EAGAIN; + ret = -EAGAIN; + if (unlikely(atomic_read(&ctx->mmap_changing))) { + if (unlikely(put_user(ret, &user_uffdio_move->move))) + return -EFAULT; + goto out; + } if (copy_from_user(&uffdio_move, user_uffdio_move, /* don't copy "move" last field */ _ Patches currently in -mm which might be from peterx(a)redhat.com are mm-selftests-add-a-test-to-verify-mmap_changing-race-with-eagain.patch

4 months, 1 week

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[merged mm-hotfixes-stable] selftests-mm-compaction_test-support-platform-with-huge-mount-of-memory.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: selftests/mm: compaction_test: support platform with huge mount of memory has been removed from the -mm tree. Its filename was selftests-mm-compaction_test-support-platform-with-huge-mount-of-memory.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: Feng Tang <feng.tang(a)linux.alibaba.com> Subject: selftests/mm: compaction_test: support platform with huge mount of memory Date: Wed, 23 Apr 2025 18:36:45 +0800 When running mm selftest to verify mm patches, 'compaction_test' case failed on an x86 server with 1TB memory. And the root cause is that it has too much free memory than what the test supports. The test case tries to allocate 100000 huge pages, which is about 200 GB for that x86 server, and when it succeeds, it expects it's large than 1/3 of 80% of the free memory in system. This logic only works for platform with 750 GB ( 200 / (1/3) / 80% ) or less free memory, and may raise false alarm for others. Fix it by changing the fixed page number to self-adjustable number according to the real number of free memory. Link: https://lkml.kernel.org/r/20250423103645.2758-1-feng.tang@linux.alibaba.com Fixes: bd67d5c15cc1 ("Test compaction of mlocked memory") Signed-off-by: Feng Tang <feng.tang(a)linux.alibaba.com> Acked-by: Dev Jain <dev.jain(a)arm.com> Reviewed-by: Baolin Wang <baolin.wang(a)linux.alibaba.com> Tested-by: Baolin Wang <baolin.wang(a)inux.alibaba.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Sri Jayaramappa <sjayaram(a)akamai.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- tools/testing/selftests/mm/compaction_test.c | 19 ++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) --- a/tools/testing/selftests/mm/compaction_test.c~selftests-mm-compaction_test-support-platform-with-huge-mount-of-memory +++ a/tools/testing/selftests/mm/compaction_test.c @@ -90,6 +90,8 @@ int check_compaction(unsigned long mem_f int compaction_index = 0; char nr_hugepages[20] = {0}; char init_nr_hugepages[24] = {0}; + char target_nr_hugepages[24] = {0}; + int slen; snprintf(init_nr_hugepages, sizeof(init_nr_hugepages), "%lu", initial_nr_hugepages); @@ -106,11 +108,18 @@ int check_compaction(unsigned long mem_f goto out; } - /* Request a large number of huge pages. The Kernel will allocate - as much as it can */ - if (write(fd, "100000", (6*sizeof(char))) != (6*sizeof(char))) { - ksft_print_msg("Failed to write 100000 to /proc/sys/vm/nr_hugepages: %s\n", - strerror(errno)); + /* + * Request huge pages for about half of the free memory. The Kernel + * will allocate as much as it can, and we expect it will get at least 1/3 + */ + nr_hugepages_ul = mem_free / hugepage_size / 2; + snprintf(target_nr_hugepages, sizeof(target_nr_hugepages), + "%lu", nr_hugepages_ul); + + slen = strlen(target_nr_hugepages); + if (write(fd, target_nr_hugepages, slen) != slen) { + ksft_print_msg("Failed to write %lu to /proc/sys/vm/nr_hugepages: %s\n", + nr_hugepages_ul, strerror(errno)); goto close_fd; } _ Patches currently in -mm which might be from feng.tang(a)linux.alibaba.com are

4 months, 1 week

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[merged mm-hotfixes-stable] v2-ocfs2-fix-panic-in-failed-foilio-allocation.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: ocfs2: fix panic in failed foilio allocation has been removed from the -mm tree. Its filename was v2-ocfs2-fix-panic-in-failed-foilio-allocation.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: Mark Tinguely <mark.tinguely(a)oracle.com> Subject: ocfs2: fix panic in failed foilio allocation Date: Fri, 11 Apr 2025 11:31:24 -0500 commit 7e119cff9d0a ("ocfs2: convert w_pages to w_folios") and commit 9a5e08652dc4b ("ocfs2: use an array of folios instead of an array of pages") save -ENOMEM in the folio array upon allocation failure and call the folio array free code. The folio array free code expects either valid folio pointers or NULL. Finding the -ENOMEM will result in a panic. Fix by NULLing the error folio entry. Link: https://lkml.kernel.org/r/c879a52b-835c-4fa0-902b-8b2e9196dcbd@oracle.com Fixes: 7e119cff9d0a ("ocfs2: convert w_pages to w_folios") Fixes: 9a5e08652dc4b ("ocfs2: use an array of folios instead of an array of pages") Signed-off-by: Mark Tinguely <mark.tinguely(a)oracle.com> Reviewed-by: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Changwei Ge <gechangwei(a)live.cn> Cc: Joel Becker <jlbec(a)evilplan.org> Cc: Junxiao Bi <junxiao.bi(a)oracle.com> Cc: Mark Fasheh <mark(a)fasheh.com> Cc: Nathan Chancellor <nathan(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/ocfs2/alloc.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/ocfs2/alloc.c~v2-ocfs2-fix-panic-in-failed-foilio-allocation +++ a/fs/ocfs2/alloc.c @@ -6918,6 +6918,7 @@ static int ocfs2_grab_folios(struct inod if (IS_ERR(folios[numfolios])) { ret = PTR_ERR(folios[numfolios]); mlog_errno(ret); + folios[numfolios] = NULL; goto out; } _ Patches currently in -mm which might be from mark.tinguely(a)oracle.com are

4 months, 1 week

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[merged mm-hotfixes-stable] mm-huge_memory-fix-dereferencing-invalid-pmd-migration-entry.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/huge_memory: fix dereferencing invalid pmd migration entry has been removed from the -mm tree. Its filename was mm-huge_memory-fix-dereferencing-invalid-pmd-migration-entry.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: Gavin Guo <gavinguo(a)igalia.com> Subject: mm/huge_memory: fix dereferencing invalid pmd migration entry Date: Mon, 21 Apr 2025 19:35:36 +0800 When migrating a THP, concurrent access to the PMD migration entry during a deferred split scan can lead to an invalid address access, as illustrated below. To prevent this invalid access, it is necessary to check the PMD migration entry and return early. In this context, there is no need to use pmd_to_swp_entry and pfn_swap_entry_to_page to verify the equality of the target folio. Since the PMD migration entry is locked, it cannot be served as the target. Mailing list discussion and explanation from Hugh Dickins: "An anon_vma lookup points to a location which may contain the folio of interest, but might instead contain another folio: and weeding out those other folios is precisely what the "folio != pmd_folio((*pmd)" check (and the "risk of replacing the wrong folio" comment a few lines above it) is for." BUG: unable to handle page fault for address: ffffea60001db008 CPU: 0 UID: 0 PID: 2199114 Comm: tee Not tainted 6.14.0+ #4 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:split_huge_pmd_locked+0x3b5/0x2b60 Call Trace: <TASK> try_to_migrate_one+0x28c/0x3730 rmap_walk_anon+0x4f6/0x770 unmap_folio+0x196/0x1f0 split_huge_page_to_list_to_order+0x9f6/0x1560 deferred_split_scan+0xac5/0x12a0 shrinker_debugfs_scan_write+0x376/0x470 full_proxy_write+0x15c/0x220 vfs_write+0x2fc/0xcb0 ksys_write+0x146/0x250 do_syscall_64+0x6a/0x120 entry_SYSCALL_64_after_hwframe+0x76/0x7e The bug is found by syzkaller on an internal kernel, then confirmed on upstream. Link: https://lkml.kernel.org/r/20250421113536.3682201-1-gavinguo@igalia.com Link: https://lore.kernel.org/all/20250414072737.1698513-1-gavinguo@igalia.com/ Link: https://lore.kernel.org/all/20250418085802.2973519-1-gavinguo@igalia.com/ Fixes: 84c3fc4e9c56 ("mm: thp: check pmd migration entry in common path") Signed-off-by: Gavin Guo <gavinguo(a)igalia.com> Acked-by: David Hildenbrand <david(a)redhat.com> Acked-by: Hugh Dickins <hughd(a)google.com> Acked-by: Zi Yan <ziy(a)nvidia.com> Reviewed-by: Gavin Shan <gshan(a)redhat.com> Cc: Florent Revest <revest(a)google.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Miaohe Lin <linmiaohe(a)huawei.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/huge_memory.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-fix-dereferencing-invalid-pmd-migration-entry +++ a/mm/huge_memory.c @@ -3075,6 +3075,8 @@ static void __split_huge_pmd_locked(stru void split_huge_pmd_locked(struct vm_area_struct *vma, unsigned long address, pmd_t *pmd, bool freeze, struct folio *folio) { + bool pmd_migration = is_pmd_migration_entry(*pmd); + VM_WARN_ON_ONCE(folio && !folio_test_pmd_mappable(folio)); VM_WARN_ON_ONCE(!IS_ALIGNED(address, HPAGE_PMD_SIZE)); VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); @@ -3085,9 +3087,12 @@ void split_huge_pmd_locked(struct vm_are * require a folio to check the PMD against. Otherwise, there * is a risk of replacing the wrong folio. */ - if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || - is_pmd_migration_entry(*pmd)) { - if (folio && folio != pmd_folio(*pmd)) + if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || pmd_migration) { + /* + * Do not apply pmd_folio() to a migration entry; and folio lock + * guarantees that it must be of the wrong folio anyway. + */ + if (folio && (pmd_migration || folio != pmd_folio(*pmd))) return; __split_huge_pmd_locked(vma, pmd, address, freeze); } _ Patches currently in -mm which might be from gavinguo(a)igalia.com are mm-huge_memory-adjust-try_to_migrate_one-and-split_huge_pmd_locked.patch mm-huge_memory-remove-useless-folio-pointers-passing.patch

4 months, 1 week

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[merged mm-hotfixes-stable] ocfs2-fix-the-issue-with-discontiguous-allocation-in-the-global_bitmap.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: ocfs2: fix the issue with discontiguous allocation in the global_bitmap has been removed from the -mm tree. Its filename was ocfs2-fix-the-issue-with-discontiguous-allocation-in-the-global_bitmap.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: Heming Zhao <heming.zhao(a)suse.com> Subject: ocfs2: fix the issue with discontiguous allocation in the global_bitmap Date: Mon, 14 Apr 2025 14:01:23 +0800 commit 4eb7b93e0310 ("ocfs2: improve write IO performance when fragmentation is high") introduced another regression. The following ocfs2-test case can trigger this issue: > discontig_runner.sh => activate_discontig_bg.sh => resv_unwritten: > ${RESV_UNWRITTEN_BIN} -f ${WORK_PLACE}/large_testfile -s 0 -l \ > $((${FILE_MAJOR_SIZE_M}*1024*1024)) In my env, test disk size (by "fdisk -l <dev>"): > 53687091200 bytes, 104857600 sectors. Above command is: > /usr/local/ocfs2-test/bin/resv_unwritten -f \ > /mnt/ocfs2/ocfs2-activate-discontig-bg-dir/large_testfile -s 0 -l \ > 53187969024 Error log: > [*] Reserve 50724M space for a LARGE file, reserve 200M space for future test. > ioctl error 28: "No space left on device" > resv allocation failed Unknown error -1 > reserve unwritten region from 0 to 53187969024. Call flow: __ocfs2_change_file_space //by ioctl OCFS2_IOC_RESVSP64 ocfs2_allocate_unwritten_extents //start:0 len:53187969024 while() + ocfs2_get_clusters //cpos:0, alloc_size:1623168 (cluster number) + ocfs2_extend_allocation + ocfs2_lock_allocators | + choose OCFS2_AC_USE_MAIN & ocfs2_cluster_group_search | + ocfs2_add_inode_data ocfs2_add_clusters_in_btree __ocfs2_claim_clusters ocfs2_claim_suballoc_bits + During the allocation of the final part of the large file (after ~47GB), no chain had the required contiguous bits_wanted. Consequently, the allocation failed. How to fix: When OCFS2 is encountering fragmented allocation, the file system should stop attempting bits_wanted contiguous allocation and instead provide the largest available contiguous free bits from the cluster groups. Link: https://lkml.kernel.org/r/20250414060125.19938-2-heming.zhao@suse.com Fixes: 4eb7b93e0310 ("ocfs2: improve write IO performance when fragmentation is high") Signed-off-by: Heming Zhao <heming.zhao(a)suse.com> Reported-by: Gautham Ananthakrishna <gautham.ananthakrishna(a)oracle.com> Reviewed-by: Joseph Qi <joseph.qi(a)linux.alibaba.com> Cc: Mark Fasheh <mark(a)fasheh.com> Cc: Joel Becker <jlbec(a)evilplan.org> Cc: Junxiao Bi <junxiao.bi(a)oracle.com> Cc: Changwei Ge <gechangwei(a)live.cn> Cc: Jun Piao <piaojun(a)huawei.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/ocfs2/suballoc.c | 38 ++++++++++++++++++++++++++++++++------ fs/ocfs2/suballoc.h | 1 + 2 files changed, 33 insertions(+), 6 deletions(-) --- a/fs/ocfs2/suballoc.c~ocfs2-fix-the-issue-with-discontiguous-allocation-in-the-global_bitmap +++ a/fs/ocfs2/suballoc.c @@ -698,10 +698,12 @@ static int ocfs2_block_group_alloc(struc bg_bh = ocfs2_block_group_alloc_contig(osb, handle, alloc_inode, ac, cl); - if (PTR_ERR(bg_bh) == -ENOSPC) + if (PTR_ERR(bg_bh) == -ENOSPC) { + ac->ac_which = OCFS2_AC_USE_MAIN_DISCONTIG; bg_bh = ocfs2_block_group_alloc_discontig(handle, alloc_inode, ac, cl); + } if (IS_ERR(bg_bh)) { status = PTR_ERR(bg_bh); bg_bh = NULL; @@ -1794,6 +1796,7 @@ static int ocfs2_search_chain(struct ocf { int status; u16 chain; + u32 contig_bits; u64 next_group; struct inode *alloc_inode = ac->ac_inode; struct buffer_head *group_bh = NULL; @@ -1819,10 +1822,21 @@ static int ocfs2_search_chain(struct ocf status = -ENOSPC; /* for now, the chain search is a bit simplistic. We just use * the 1st group with any empty bits. */ - while ((status = ac->ac_group_search(alloc_inode, group_bh, - bits_wanted, min_bits, - ac->ac_max_block, - res)) == -ENOSPC) { + while (1) { + if (ac->ac_which == OCFS2_AC_USE_MAIN_DISCONTIG) { + contig_bits = le16_to_cpu(bg->bg_contig_free_bits); + if (!contig_bits) + contig_bits = ocfs2_find_max_contig_free_bits(bg->bg_bitmap, + le16_to_cpu(bg->bg_bits), 0); + if (bits_wanted > contig_bits && contig_bits >= min_bits) + bits_wanted = contig_bits; + } + + status = ac->ac_group_search(alloc_inode, group_bh, + bits_wanted, min_bits, + ac->ac_max_block, res); + if (status != -ENOSPC) + break; if (!bg->bg_next_group) break; @@ -1982,6 +1996,7 @@ static int ocfs2_claim_suballoc_bits(str victim = ocfs2_find_victim_chain(cl); ac->ac_chain = victim; +search: status = ocfs2_search_chain(ac, handle, bits_wanted, min_bits, res, &bits_left); if (!status) { @@ -2022,6 +2037,16 @@ static int ocfs2_claim_suballoc_bits(str } } + /* Chains can't supply the bits_wanted contiguous space. + * We should switch to using every single bit when allocating + * from the global bitmap. */ + if (i == le16_to_cpu(cl->cl_next_free_rec) && + status == -ENOSPC && ac->ac_which == OCFS2_AC_USE_MAIN) { + ac->ac_which = OCFS2_AC_USE_MAIN_DISCONTIG; + ac->ac_chain = victim; + goto search; + } + set_hint: if (status != -ENOSPC) { /* If the next search of this group is not likely to @@ -2365,7 +2390,8 @@ int __ocfs2_claim_clusters(handle_t *han BUG_ON(ac->ac_bits_given >= ac->ac_bits_wanted); BUG_ON(ac->ac_which != OCFS2_AC_USE_LOCAL - && ac->ac_which != OCFS2_AC_USE_MAIN); + && ac->ac_which != OCFS2_AC_USE_MAIN + && ac->ac_which != OCFS2_AC_USE_MAIN_DISCONTIG); if (ac->ac_which == OCFS2_AC_USE_LOCAL) { WARN_ON(min_clusters > 1); --- a/fs/ocfs2/suballoc.h~ocfs2-fix-the-issue-with-discontiguous-allocation-in-the-global_bitmap +++ a/fs/ocfs2/suballoc.h @@ -29,6 +29,7 @@ struct ocfs2_alloc_context { #define OCFS2_AC_USE_MAIN 2 #define OCFS2_AC_USE_INODE 3 #define OCFS2_AC_USE_META 4 +#define OCFS2_AC_USE_MAIN_DISCONTIG 5 u32 ac_which; /* these are used by the chain search */ _ Patches currently in -mm which might be from heming.zhao(a)suse.com are

4 months, 1 week

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+ x86-kexec-fix-potential-cmem-ranges-out-of-bounds.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: x86/kexec: fix potential cmem->ranges out of bounds has been added to the -mm mm-hotfixes-unstable branch. Its filename is x86-kexec-fix-potential-cmem-ranges-out-of-bounds.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: fuqiang wang <fuqiang.wang(a)easystack.cn> Subject: x86/kexec: fix potential cmem->ranges out of bounds Date: Mon, 8 Jan 2024 21:06:47 +0800 In memmap_exclude_ranges(), elfheader will be excluded from crashk_res. In the current x86 architecture code, the elfheader is always allocated at crashk_res.start. It seems that there won't be a new split range. But it depends on the allocation position of elfheader in crashk_res. To avoid potential out of bounds in future, add a extra slot. The similar issue also exists in fill_up_crash_elf_data(). The range to be excluded is [0, 1M], start (0) is special and will not appear in the middle of existing cmem->ranges[]. But in cast the low 1M could be changed in the future, add a extra slot too. Without this patch, kdump kernel will fail to be loaded by kexec_file_load, [ 139.736948] UBSAN: array-index-out-of-bounds in arch/x86/kernel/crash.c:350:25 [ 139.742360] index 0 is out of range for type 'range [*]' [ 139.745695] CPU: 0 UID: 0 PID: 5778 Comm: kexec Not tainted 6.15.0-0.rc3.20250425git02ddfb981de8.32.fc43.x86_64 #1 PREEMPT(lazy) [ 139.745698] Hardware name: Amazon EC2 c5.large/, BIOS 1.0 10/16/2017 [ 139.745699] Call Trace: [ 139.745700] <TASK> [ 139.745701] dump_stack_lvl+0x5d/0x80 [ 139.745706] ubsan_epilogue+0x5/0x2b [ 139.745709] __ubsan_handle_out_of_bounds.cold+0x54/0x59 [ 139.745711] crash_setup_memmap_entries+0x2d9/0x330 [ 139.745716] setup_boot_parameters+0xf8/0x6a0 [ 139.745720] bzImage64_load+0x41b/0x4e0 [ 139.745722] ? find_next_iomem_res+0x109/0x140 [ 139.745727] ? locate_mem_hole_callback+0x109/0x170 [ 139.745737] kimage_file_alloc_init+0x1ef/0x3e0 [ 139.745740] __do_sys_kexec_file_load+0x180/0x2f0 [ 139.745742] do_syscall_64+0x7b/0x160 [ 139.745745] ? do_user_addr_fault+0x21a/0x690 [ 139.745747] ? exc_page_fault+0x7e/0x1a0 [ 139.745749] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 139.745751] RIP: 0033:0x7f7712c84e4d Previously discussed link: [1] https://lore.kernel.org/kexec/ZXk2oBf%2FT1Ul6o0c@MiWiFi-R3L-srv/ [2] https://lore.kernel.org/kexec/273284e8-7680-4f5f-8065-c5d780987e59@easystac… [3] https://lore.kernel.org/kexec/ZYQ6O%2F57sHAPxTHm@MiWiFi-R3L-srv/ Link: https://lkml.kernel.org/r/20240108130720.228478-1-fuqiang.wang@easystack.cn Signed-off-by: fuqiang wang <fuqiang.wang(a)easystack.cn> Acked-by: Baoquan He <bhe(a)redhat.com> Reported-by: Coiby Xu <coxu(a)redhat.com> Closes: https://lkml.kernel.org/r/4de3c2onosr7negqnfhekm4cpbklzmsimgdfv33c52dktqpza… Cc: Vivek Goyal <vgoyal(a)redhat.com> Cc: Dave Young <dyoung(a)redhat.com> Cc: <x86(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- arch/x86/kernel/crash.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/crash.c~x86-kexec-fix-potential-cmem-ranges-out-of-bounds +++ a/arch/x86/kernel/crash.c @@ -165,8 +165,18 @@ static struct crash_mem *fill_up_crash_e /* * Exclusion of crash region and/or crashk_low_res may cause * another range split. So add extra two slots here. + * + * Exclusion of low 1M may not cause another range split, because the + * range of exclude is [0, 1M] and the condition for splitting a new + * region is that the start, end parameters are both in a certain + * existing region in cmem and cannot be equal to existing region's + * start or end. Obviously, the start of [0, 1M] cannot meet this + * condition. + * + * But in order to lest the low 1M could be changed in the future, + * (e.g. [stare, 1M]), add a extra slot. */ - nr_ranges += 2; + nr_ranges += 3; cmem = vzalloc(struct_size(cmem, ranges, nr_ranges)); if (!cmem) return NULL; @@ -298,9 +308,16 @@ int crash_setup_memmap_entries(struct ki struct crash_memmap_data cmd; struct crash_mem *cmem; - cmem = vzalloc(struct_size(cmem, ranges, 1)); + /* + * In the current x86 architecture code, the elfheader is always + * allocated at crashk_res.start. But it depends on the allocation + * position of elfheader in crashk_res. To avoid potential out of + * bounds in future, add a extra slot. + */ + cmem = vzalloc(struct_size(cmem, ranges, 2)); if (!cmem) return -ENOMEM; + cmem->max_nr_ranges = 2; memset(&cmd, 0, sizeof(struct crash_memmap_data)); cmd.params = params; _ Patches currently in -mm which might be from fuqiang.wang(a)easystack.cn are x86-kexec-fix-potential-cmem-ranges-out-of-bounds.patch

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