June 2024 - Linux-stable-mirror

[v2 PATCH] mm: gup: do not call try_grab_folio() in slow path

by Yang Shi

The try_grab_folio() is supposed to be used in fast path and it elevates folio refcount by using add ref unless zero. We are guaranteed to have at least one stable reference in slow path, so the simple atomic add could be used. The performance difference should be trivial, but the misuse may be confusing and misleading. In another thread [1] a kernel warning was reported when pinning folio in CMA memory when launching SEV virtual machine. The splat looks like: [ 464.325306] WARNING: CPU: 13 PID: 6734 at mm/gup.c:1313 __get_user_pages+0x423/0x520 [ 464.325464] CPU: 13 PID: 6734 Comm: qemu-kvm Kdump: loaded Not tainted 6.6.33+ #6 [ 464.325477] RIP: 0010:__get_user_pages+0x423/0x520 [ 464.325515] Call Trace: [ 464.325520] <TASK> [ 464.325523] ? __get_user_pages+0x423/0x520 [ 464.325528] ? __warn+0x81/0x130 [ 464.325536] ? __get_user_pages+0x423/0x520 [ 464.325541] ? report_bug+0x171/0x1a0 [ 464.325549] ? handle_bug+0x3c/0x70 [ 464.325554] ? exc_invalid_op+0x17/0x70 [ 464.325558] ? asm_exc_invalid_op+0x1a/0x20 [ 464.325567] ? __get_user_pages+0x423/0x520 [ 464.325575] __gup_longterm_locked+0x212/0x7a0 [ 464.325583] internal_get_user_pages_fast+0xfb/0x190 [ 464.325590] pin_user_pages_fast+0x47/0x60 [ 464.325598] sev_pin_memory+0xca/0x170 [kvm_amd] [ 464.325616] sev_mem_enc_register_region+0x81/0x130 [kvm_amd] Per the analysis done by yangge, when starting the SEV virtual machine, it will call pin_user_pages_fast(..., FOLL_LONGTERM, ...) to pin the memory. But the page is in CMA area, so fast GUP will fail then fallback to the slow path due to the longterm pinnalbe check in try_grab_folio(). The slow path will try to pin the pages then migrate them out of CMA area. But the slow path also uses try_grab_folio() to pin the page, it will also fail due to the same check then the above warning is triggered. [1] https://lore.kernel.org/linux-mm/1719478388-31917-1-git-send-email-yangge11… Fixes: 57edfcfd3419 ("mm/gup: accelerate thp gup even for "pages != NULL"") Cc: <stable(a)vger.kernel.org> [6.6+] Reported-by: yangge <yangge1116(a)126.com> Signed-off-by: Yang Shi <yang(a)os.amperecomputing.com> --- mm/gup.c | 285 +++++++++++++++++++++++++---------------------- mm/huge_memory.c | 2 +- mm/internal.h | 3 +- 3 files changed, 152 insertions(+), 138 deletions(-) v2: 1. Fixed the build warning 2. Reworked the commit log to include the bug report and analysis (reworded by me) from yangge 3. Rebased onto the latest mm-unstable diff --git a/mm/gup.c b/mm/gup.c index 8bea9ad80984..7439359d0b71 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -99,95 +99,6 @@ static inline struct folio *try_get_folio(struct page *page, int refs) return folio; } -/** - * try_grab_folio() - Attempt to get or pin a folio. - * @page: pointer to page to be grabbed - * @refs: the value to (effectively) add to the folio's refcount - * @flags: gup flags: these are the FOLL_* flag values. - * - * "grab" names in this file mean, "look at flags to decide whether to use - * FOLL_PIN or FOLL_GET behavior, when incrementing the folio's refcount. - * - * Either FOLL_PIN or FOLL_GET (or neither) must be set, but not both at the - * same time. (That's true throughout the get_user_pages*() and - * pin_user_pages*() APIs.) Cases: - * - * FOLL_GET: folio's refcount will be incremented by @refs. - * - * FOLL_PIN on large folios: folio's refcount will be incremented by - * @refs, and its pincount will be incremented by @refs. - * - * FOLL_PIN on single-page folios: folio's refcount will be incremented by - * @refs * GUP_PIN_COUNTING_BIAS. - * - * Return: The folio containing @page (with refcount appropriately - * incremented) for success, or NULL upon failure. If neither FOLL_GET - * nor FOLL_PIN was set, that's considered failure, and furthermore, - * a likely bug in the caller, so a warning is also emitted. - */ -struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags) -{ - struct folio *folio; - - if (WARN_ON_ONCE((flags & (FOLL_GET | FOLL_PIN)) == 0)) - return NULL; - - if (unlikely(!(flags & FOLL_PCI_P2PDMA) && is_pci_p2pdma_page(page))) - return NULL; - - if (flags & FOLL_GET) - return try_get_folio(page, refs); - - /* FOLL_PIN is set */ - - /* - * Don't take a pin on the zero page - it's not going anywhere - * and it is used in a *lot* of places. - */ - if (is_zero_page(page)) - return page_folio(page); - - folio = try_get_folio(page, refs); - if (!folio) - return NULL; - - /* - * Can't do FOLL_LONGTERM + FOLL_PIN gup fast path if not in a - * right zone, so fail and let the caller fall back to the slow - * path. - */ - if (unlikely((flags & FOLL_LONGTERM) && - !folio_is_longterm_pinnable(folio))) { - if (!put_devmap_managed_folio_refs(folio, refs)) - folio_put_refs(folio, refs); - return NULL; - } - - /* - * When pinning a large folio, use an exact count to track it. - * - * However, be sure to *also* increment the normal folio - * refcount field at least once, so that the folio really - * is pinned. That's why the refcount from the earlier - * try_get_folio() is left intact. - */ - if (folio_test_large(folio)) - atomic_add(refs, &folio->_pincount); - else - folio_ref_add(folio, - refs * (GUP_PIN_COUNTING_BIAS - 1)); - /* - * Adjust the pincount before re-checking the PTE for changes. - * This is essentially a smp_mb() and is paired with a memory - * barrier in folio_try_share_anon_rmap_*(). - */ - smp_mb__after_atomic(); - - node_stat_mod_folio(folio, NR_FOLL_PIN_ACQUIRED, refs); - - return folio; -} - static void gup_put_folio(struct folio *folio, int refs, unsigned int flags) { if (flags & FOLL_PIN) { @@ -205,28 +116,31 @@ static void gup_put_folio(struct folio *folio, int refs, unsigned int flags) } /** - * try_grab_page() - elevate a page's refcount by a flag-dependent amount - * @page: pointer to page to be grabbed - * @flags: gup flags: these are the FOLL_* flag values. + * try_grab_folio() - add a folio's refcount by a flag-dependent amount + * @folio: pointer to folio to be grabbed + * @refs: the value to (effectively) add to the folio's refcount + * @flags: gup flags: these are the FOLL_* flag values * * This might not do anything at all, depending on the flags argument. * * "grab" names in this file mean, "look at flags to decide whether to use - * FOLL_PIN or FOLL_GET behavior, when incrementing the page's refcount. + * FOLL_PIN or FOLL_GET behavior, when incrementing the folio's refcount. * * Either FOLL_PIN or FOLL_GET (or neither) may be set, but not both at the same - * time. Cases: please see the try_grab_folio() documentation, with - * "refs=1". + * time. * * Return: 0 for success, or if no action was required (if neither FOLL_PIN * nor FOLL_GET was set, nothing is done). A negative error code for failure: * - * -ENOMEM FOLL_GET or FOLL_PIN was set, but the page could not + * -ENOMEM FOLL_GET or FOLL_PIN was set, but the folio could not * be grabbed. + * + * It is called when we have a stable reference for the folio, typically in + * GUP slow path. */ -int __must_check try_grab_page(struct page *page, unsigned int flags) +int __must_check try_grab_folio(struct folio *folio, int refs, unsigned int flags) { - struct folio *folio = page_folio(page); + struct page *page = &folio->page; if (WARN_ON_ONCE(folio_ref_count(folio) <= 0)) return -ENOMEM; @@ -235,7 +149,7 @@ int __must_check try_grab_page(struct page *page, unsigned int flags) return -EREMOTEIO; if (flags & FOLL_GET) - folio_ref_inc(folio); + folio_ref_add(folio, refs); else if (flags & FOLL_PIN) { /* * Don't take a pin on the zero page - it's not going anywhere @@ -245,18 +159,18 @@ int __must_check try_grab_page(struct page *page, unsigned int flags) return 0; /* - * Similar to try_grab_folio(): be sure to *also* - * increment the normal page refcount field at least once, + * Increment the normal page refcount field at least once, * so that the page really is pinned. */ if (folio_test_large(folio)) { - folio_ref_add(folio, 1); - atomic_add(1, &folio->_pincount); + folio_ref_add(folio, refs); + atomic_add(refs, &folio->_pincount); } else { - folio_ref_add(folio, GUP_PIN_COUNTING_BIAS); + folio_ref_add(folio, + refs * GUP_PIN_COUNTING_BIAS); } - node_stat_mod_folio(folio, NR_FOLL_PIN_ACQUIRED, 1); + node_stat_mod_folio(folio, NR_FOLL_PIN_ACQUIRED, refs); } return 0; @@ -584,7 +498,7 @@ static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end, */ static int gup_hugepte(struct vm_area_struct *vma, pte_t *ptep, unsigned long sz, unsigned long addr, unsigned long end, unsigned int flags, - struct page **pages, int *nr) + struct page **pages, int *nr, bool fast) { unsigned long pte_end; struct page *page; @@ -607,9 +521,15 @@ static int gup_hugepte(struct vm_area_struct *vma, pte_t *ptep, unsigned long sz page = pte_page(pte); refs = record_subpages(page, sz, addr, end, pages + *nr); - folio = try_grab_folio(page, refs, flags); - if (!folio) - return 0; + if (fast) { + folio = try_grab_folio_fast(page, refs, flags); + if (!folio) + return 0; + } else { + folio = page_folio(page); + if (try_grab_folio(folio, refs, flags)) + return 0; + } if (unlikely(pte_val(pte) != pte_val(ptep_get(ptep)))) { gup_put_folio(folio, refs, flags); @@ -637,7 +557,7 @@ static int gup_hugepte(struct vm_area_struct *vma, pte_t *ptep, unsigned long sz static int gup_hugepd(struct vm_area_struct *vma, hugepd_t hugepd, unsigned long addr, unsigned int pdshift, unsigned long end, unsigned int flags, - struct page **pages, int *nr) + struct page **pages, int *nr, bool fast) { pte_t *ptep; unsigned long sz = 1UL << hugepd_shift(hugepd); @@ -647,7 +567,7 @@ static int gup_hugepd(struct vm_area_struct *vma, hugepd_t hugepd, ptep = hugepte_offset(hugepd, addr, pdshift); do { next = hugepte_addr_end(addr, end, sz); - ret = gup_hugepte(vma, ptep, sz, addr, end, flags, pages, nr); + ret = gup_hugepte(vma, ptep, sz, addr, end, flags, pages, nr, fast); if (ret != 1) return ret; } while (ptep++, addr = next, addr != end); @@ -674,7 +594,7 @@ static struct page *follow_hugepd(struct vm_area_struct *vma, hugepd_t hugepd, ptep = hugepte_offset(hugepd, addr, pdshift); ptl = huge_pte_lock(h, vma->vm_mm, ptep); ret = gup_hugepd(vma, hugepd, addr, pdshift, addr + PAGE_SIZE, - flags, &page, &nr); + flags, &page, &nr, false); spin_unlock(ptl); if (ret == 1) { @@ -691,7 +611,7 @@ static struct page *follow_hugepd(struct vm_area_struct *vma, hugepd_t hugepd, static inline int gup_hugepd(struct vm_area_struct *vma, hugepd_t hugepd, unsigned long addr, unsigned int pdshift, unsigned long end, unsigned int flags, - struct page **pages, int *nr) + struct page **pages, int *nr, bool fast) { return 0; } @@ -778,7 +698,7 @@ static struct page *follow_huge_pud(struct vm_area_struct *vma, gup_must_unshare(vma, flags, page)) return ERR_PTR(-EMLINK); - ret = try_grab_page(page, flags); + ret = try_grab_folio(page_folio(page), 1, flags); if (ret) page = ERR_PTR(ret); else @@ -855,7 +775,7 @@ static struct page *follow_huge_pmd(struct vm_area_struct *vma, VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && !PageAnonExclusive(page), page); - ret = try_grab_page(page, flags); + ret = try_grab_folio(page_folio(page), 1, flags); if (ret) return ERR_PTR(ret); @@ -1017,8 +937,8 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && !PageAnonExclusive(page), page); - /* try_grab_page() does nothing unless FOLL_GET or FOLL_PIN is set. */ - ret = try_grab_page(page, flags); + /* try_grab_folio() does nothing unless FOLL_GET or FOLL_PIN is set. */ + ret = try_grab_folio(page_folio(page), 1, flags); if (unlikely(ret)) { page = ERR_PTR(ret); goto out; @@ -1282,7 +1202,7 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, goto unmap; *page = pte_page(entry); } - ret = try_grab_page(*page, gup_flags); + ret = try_grab_folio(page_folio(*page), 1, gup_flags); if (unlikely(ret)) goto unmap; out: @@ -1685,20 +1605,19 @@ static long __get_user_pages(struct mm_struct *mm, * pages. */ if (page_increm > 1) { - struct folio *folio; + struct folio *folio = page_folio(page); /* * Since we already hold refcount on the * large folio, this should never fail. */ - folio = try_grab_folio(page, page_increm - 1, - foll_flags); - if (WARN_ON_ONCE(!folio)) { + if (try_grab_folio(folio, page_increm - 1, + foll_flags)) { /* * Release the 1st page ref if the * folio is problematic, fail hard. */ - gup_put_folio(page_folio(page), 1, + gup_put_folio(folio, 1, foll_flags); ret = -EFAULT; goto out; @@ -2876,6 +2795,101 @@ EXPORT_SYMBOL(get_user_pages_unlocked); * This code is based heavily on the PowerPC implementation by Nick Piggin. */ #ifdef CONFIG_HAVE_GUP_FAST +/** + * try_grab_folio_fast() - Attempt to get or pin a folio in fast path. + * @page: pointer to page to be grabbed + * @refs: the value to (effectively) add to the folio's refcount + * @flags: gup flags: these are the FOLL_* flag values. + * + * "grab" names in this file mean, "look at flags to decide whether to use + * FOLL_PIN or FOLL_GET behavior, when incrementing the folio's refcount. + * + * Either FOLL_PIN or FOLL_GET (or neither) must be set, but not both at the + * same time. (That's true throughout the get_user_pages*() and + * pin_user_pages*() APIs.) Cases: + * + * FOLL_GET: folio's refcount will be incremented by @refs. + * + * FOLL_PIN on large folios: folio's refcount will be incremented by + * @refs, and its pincount will be incremented by @refs. + * + * FOLL_PIN on single-page folios: folio's refcount will be incremented by + * @refs * GUP_PIN_COUNTING_BIAS. + * + * Return: The folio containing @page (with refcount appropriately + * incremented) for success, or NULL upon failure. If neither FOLL_GET + * nor FOLL_PIN was set, that's considered failure, and furthermore, + * a likely bug in the caller, so a warning is also emitted. + * + * It uses add ref unless zero to elevate the folio refcount and must be called + * in fast path only. + */ +static struct folio *try_grab_folio_fast(struct page *page, int refs, + unsigned int flags) +{ + struct folio *folio; + + /* Raise warn if it is not called in fast GUP */ + VM_WARN_ON_ONCE(!irqs_disabled()); + + if (WARN_ON_ONCE((flags & (FOLL_GET | FOLL_PIN)) == 0)) + return NULL; + + if (unlikely(!(flags & FOLL_PCI_P2PDMA) && is_pci_p2pdma_page(page))) + return NULL; + + if (flags & FOLL_GET) + return try_get_folio(page, refs); + + /* FOLL_PIN is set */ + + /* + * Don't take a pin on the zero page - it's not going anywhere + * and it is used in a *lot* of places. + */ + if (is_zero_page(page)) + return page_folio(page); + + folio = try_get_folio(page, refs); + if (!folio) + return NULL; + + /* + * Can't do FOLL_LONGTERM + FOLL_PIN gup fast path if not in a + * right zone, so fail and let the caller fall back to the slow + * path. + */ + if (unlikely((flags & FOLL_LONGTERM) && + !folio_is_longterm_pinnable(folio))) { + if (!put_devmap_managed_folio_refs(folio, refs)) + folio_put_refs(folio, refs); + return NULL; + } + + /* + * When pinning a large folio, use an exact count to track it. + * + * However, be sure to *also* increment the normal folio + * refcount field at least once, so that the folio really + * is pinned. That's why the refcount from the earlier + * try_get_folio() is left intact. + */ + if (folio_test_large(folio)) + atomic_add(refs, &folio->_pincount); + else + folio_ref_add(folio, + refs * (GUP_PIN_COUNTING_BIAS - 1)); + /* + * Adjust the pincount before re-checking the PTE for changes. + * This is essentially a smp_mb() and is paired with a memory + * barrier in folio_try_share_anon_rmap_*(). + */ + smp_mb__after_atomic(); + + node_stat_mod_folio(folio, NR_FOLL_PIN_ACQUIRED, refs); + + return folio; +} /* * Used in the GUP-fast path to determine whether GUP is permitted to work on @@ -3041,7 +3055,7 @@ static int gup_fast_pte_range(pmd_t pmd, pmd_t *pmdp, unsigned long addr, VM_BUG_ON(!pfn_valid(pte_pfn(pte))); page = pte_page(pte); - folio = try_grab_folio(page, 1, flags); + folio = try_grab_folio_fast(page, 1, flags); if (!folio) goto pte_unmap; @@ -3128,7 +3142,7 @@ static int gup_fast_devmap_leaf(unsigned long pfn, unsigned long addr, break; } - folio = try_grab_folio(page, 1, flags); + folio = try_grab_folio_fast(page, 1, flags); if (!folio) { gup_fast_undo_dev_pagemap(nr, nr_start, flags, pages); break; @@ -3217,7 +3231,7 @@ static int gup_fast_pmd_leaf(pmd_t orig, pmd_t *pmdp, unsigned long addr, page = pmd_page(orig); refs = record_subpages(page, PMD_SIZE, addr, end, pages + *nr); - folio = try_grab_folio(page, refs, flags); + folio = try_grab_folio_fast(page, refs, flags); if (!folio) return 0; @@ -3261,7 +3275,7 @@ static int gup_fast_pud_leaf(pud_t orig, pud_t *pudp, unsigned long addr, page = pud_page(orig); refs = record_subpages(page, PUD_SIZE, addr, end, pages + *nr); - folio = try_grab_folio(page, refs, flags); + folio = try_grab_folio_fast(page, refs, flags); if (!folio) return 0; @@ -3301,7 +3315,7 @@ static int gup_fast_pgd_leaf(pgd_t orig, pgd_t *pgdp, unsigned long addr, page = pgd_page(orig); refs = record_subpages(page, PGDIR_SIZE, addr, end, pages + *nr); - folio = try_grab_folio(page, refs, flags); + folio = try_grab_folio_fast(page, refs, flags); if (!folio) return 0; @@ -3355,7 +3369,7 @@ static int gup_fast_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr, * pmd format and THP pmd format */ if (gup_hugepd(NULL, __hugepd(pmd_val(pmd)), addr, - PMD_SHIFT, next, flags, pages, nr) != 1) + PMD_SHIFT, next, flags, pages, nr, true) != 1) return 0; } else if (!gup_fast_pte_range(pmd, pmdp, addr, next, flags, pages, nr)) @@ -3385,7 +3399,7 @@ static int gup_fast_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, return 0; } else if (unlikely(is_hugepd(__hugepd(pud_val(pud))))) { if (gup_hugepd(NULL, __hugepd(pud_val(pud)), addr, - PUD_SHIFT, next, flags, pages, nr) != 1) + PUD_SHIFT, next, flags, pages, nr, true) != 1) return 0; } else if (!gup_fast_pmd_range(pudp, pud, addr, next, flags, pages, nr)) @@ -3412,7 +3426,7 @@ static int gup_fast_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, BUILD_BUG_ON(p4d_leaf(p4d)); if (unlikely(is_hugepd(__hugepd(p4d_val(p4d))))) { if (gup_hugepd(NULL, __hugepd(p4d_val(p4d)), addr, - P4D_SHIFT, next, flags, pages, nr) != 1) + P4D_SHIFT, next, flags, pages, nr, true) != 1) return 0; } else if (!gup_fast_pud_range(p4dp, p4d, addr, next, flags, pages, nr)) @@ -3441,7 +3455,7 @@ static void gup_fast_pgd_range(unsigned long addr, unsigned long end, return; } else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) { if (gup_hugepd(NULL, __hugepd(pgd_val(pgd)), addr, - PGDIR_SHIFT, next, flags, pages, nr) != 1) + PGDIR_SHIFT, next, flags, pages, nr, true) != 1) return; } else if (!gup_fast_p4d_range(pgdp, pgd, addr, next, flags, pages, nr)) @@ -3842,14 +3856,15 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, next_idx != folio_index(fbatch.folios[i])) continue; - folio = try_grab_folio(&fbatch.folios[i]->page, - 1, FOLL_PIN); - if (!folio) { + if (try_grab_folio(fbatch.folios[i], + 1, FOLL_PIN)) { folio_batch_release(&fbatch); ret = -EINVAL; goto err; } + folio = fbatch.folios[i]; + if (nr_folios == 0) *offset = offset_in_folio(folio, start); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index c7ce28f6b7f3..954c63575917 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1333,7 +1333,7 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, if (!*pgmap) return ERR_PTR(-EFAULT); page = pfn_to_page(pfn); - ret = try_grab_page(page, flags); + ret = try_grab_folio(page_folio(page), 1, flags); if (ret) page = ERR_PTR(ret); diff --git a/mm/internal.h b/mm/internal.h index 2ea9a88dcb95..b264a7dabefe 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1226,8 +1226,7 @@ int migrate_device_coherent_page(struct page *page); /* * mm/gup.c */ -struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags); -int __must_check try_grab_page(struct page *page, unsigned int flags); +int __must_check try_grab_folio(struct folio *folio, int refs, unsigned int flags); /* * mm/huge_memory.c -- 2.41.0

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+ nilfs2-fix-kernel-bug-on-rename-operation-of-broken-directory.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: nilfs2: fix kernel bug on rename operation of broken directory has been added to the -mm mm-hotfixes-unstable branch. Its filename is nilfs2-fix-kernel-bug-on-rename-operation-of-broken-directory.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: Ryusuke Konishi <konishi.ryusuke(a)gmail.com> Subject: nilfs2: fix kernel bug on rename operation of broken directory Date: Sat, 29 Jun 2024 01:51:07 +0900 Syzbot reported that in rename directory operation on broken directory on nilfs2, __block_write_begin_int() called to prepare block write may fail BUG_ON check for access exceeding the folio/page size. This is because nilfs_dotdot(), which gets parent directory reference entry ("..") of the directory to be moved or renamed, does not check consistency enough, and may return location exceeding folio/page size for broken directories. Fix this issue by checking required directory entries ("." and "..") in the first chunk of the directory in nilfs_dotdot(). Link: https://lkml.kernel.org/r/20240628165107.9006-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi <konishi.ryusuke(a)gmail.com> Reported-by: syzbot+d3abed1ad3d367fa2627(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d3abed1ad3d367fa2627 Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations") Tested-by: Ryusuke Konishi <konishi.ryusuke(a)gmail.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/nilfs2/dir.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) --- a/fs/nilfs2/dir.c~nilfs2-fix-kernel-bug-on-rename-operation-of-broken-directory +++ a/fs/nilfs2/dir.c @@ -383,11 +383,39 @@ found: struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct folio **foliop) { - struct nilfs_dir_entry *de = nilfs_get_folio(dir, 0, foliop); + struct folio *folio; + struct nilfs_dir_entry *de, *next_de; + size_t limit; + char *msg; + de = nilfs_get_folio(dir, 0, &folio); if (IS_ERR(de)) return NULL; - return nilfs_next_entry(de); + + limit = nilfs_last_byte(dir, 0); /* is a multiple of chunk size */ + if (unlikely(!limit || le64_to_cpu(de->inode) != dir->i_ino || + !nilfs_match(1, ".", de))) { + msg = "missing '.'"; + goto fail; + } + + next_de = nilfs_next_entry(de); + /* + * If "next_de" has not reached the end of the chunk, there is + * at least one more record. Check whether it matches "..". + */ + if (unlikely((char *)next_de == (char *)de + nilfs_chunk_size(dir) || + !nilfs_match(2, "..", next_de))) { + msg = "missing '..'"; + goto fail; + } + *foliop = folio; + return next_de; + +fail: + nilfs_error(dir->i_sb, "directory #%lu %s", dir->i_ino, msg); + folio_release_kmap(folio, de); + return NULL; } ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr) _ Patches currently in -mm which might be from konishi.ryusuke(a)gmail.com are nilfs2-fix-kernel-bug-on-rename-operation-of-broken-directory.patch

6 months

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[PATCH 2/8] lpfc: Allow DEVICE_RECOVERY mode after RSCN receipt if in PRLI_ISSUE state

by Justin Tee

Certain vendor specific targets initially register with the fabric as an initiator function first and then re-register as a target function afterwards. The timing of the target function re-registration can cause a race condition such that the driver is stuck assuming the remote port as an initiator function and never discovers the target's hosted LUNs. Expand the nlp_state qualifier to also include NLP_STE_PRLI_ISSUE because the state means that PRLI was issued but we have not quite reached MAPPED_NODE state yet. If we received an RSCN in the PRLI_ISSUE state, then we should restart discovery again by going into DEVICE_RECOVERY. Fixes: dded1dc31aa4 ("scsi: lpfc: Modify when a node should be put in device recovery mode during RSCN") Cc: <stable(a)vger.kernel.org> # v6.6+ Signed-off-by: Justin Tee <justin.tee(a)broadcom.com> --- drivers/scsi/lpfc/lpfc_hbadisc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c index 153770bdc56a..13b08c85440f 100644 --- a/drivers/scsi/lpfc/lpfc_hbadisc.c +++ b/drivers/scsi/lpfc/lpfc_hbadisc.c @@ -5725,7 +5725,7 @@ lpfc_setup_disc_node(struct lpfc_vport *vport, uint32_t did) return ndlp; if (ndlp->nlp_state > NLP_STE_UNUSED_NODE && - ndlp->nlp_state < NLP_STE_PRLI_ISSUE) { + ndlp->nlp_state <= NLP_STE_PRLI_ISSUE) { lpfc_disc_state_machine(vport, ndlp, NULL, NLP_EVT_DEVICE_RECOVERY); } -- 2.38.0

6 months

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[STABLE] Please add two upstream patches into stable series

by Helge Deller

Hi Greg & Sasha, the following two upstream commits missed the "stable" tag, so could you please add them manually to stable series? a) commit 403f17a330732a666ae793f3b15bc75bb5540524 Author: Arnd Bergmann <arnd(a)arndb.de> Date: Fri Jun 7 13:40:45 2024 +0200 parisc: use generic sys_fanotify_mark implementation -> please include into kernel v5.11+ b) commit 20a50787349fadf66ac5c48f62e58d753878d2bb Author: Arnd Bergmann <arnd(a)arndb.de> Date: Wed Jun 19 14:27:55 2024 +0200 parisc: use correct compat recv/recvfrom syscalls -> please include into kernel v5.4+ Thanks! Helge

6 months

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[PATCH V2 1/1] block: check bio alignment in blk_mq_submit_bio

by Ming Lei

IO logical block size is one fundamental queue limit, and every IO has to be aligned with logical block size because our bio split can't deal with unaligned bio. The check has to be done with queue usage counter grabbed because device reconfiguration may change logical block size, and we can prevent the reconfiguration from happening by holding queue usage counter. logical_block_size stays in the 1st cache line of queue_limits, and this cache line is always fetched in fast path via bio_may_exceed_limits(), so IO perf won't be affected by this check. Cc: Yi Zhang <yi.zhang(a)redhat.com> Cc: Christoph Hellwig <hch(a)infradead.org> Cc: Ye Bin <yebin10(a)huawei.com> Cc: stable(a)vger.kernel.org Signed-off-by: Ming Lei <ming.lei(a)redhat.com> --- V2: - cover any zero sized bio which .bi_sector needs to be initialized too block/blk-mq.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index 3b4df8e5ac9e..d161682ecd20 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2914,6 +2914,17 @@ static void blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug, INIT_LIST_HEAD(&rq->queuelist); } +static bool bio_unaligned(const struct bio *bio, struct request_queue *q) +{ + unsigned int bs_mask = queue_logical_block_size(q) - 1; + + /* .bi_sector of any zero sized bio need to be initialized */ + if ((bio->bi_iter.bi_size & bs_mask) || + ((bio->bi_iter.bi_sector << SECTOR_SHIFT) & bs_mask)) + return true; + return false; +} + /** * blk_mq_submit_bio - Create and send a request to block device. * @bio: Bio pointer. @@ -2966,6 +2977,15 @@ void blk_mq_submit_bio(struct bio *bio) return; } + /* + * Device reconfiguration may change logical block size, so alignment + * check has to be done with queue usage counter held + */ + if (unlikely(bio_unaligned(bio, q))) { + bio_io_error(bio); + goto queue_exit; + } + if (unlikely(bio_may_exceed_limits(bio, &q->limits))) { bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); if (!bio) -- 2.44.0

6 months

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[PATCH] tty: mxser: Remove __counted_by from mxser_board.ports[]

by Nathan Chancellor

Work for __counted_by on generic pointers in structures (not just flexible array members) has started landing in Clang 19 (current tip of tree). During the development of this feature, a restriction was added to __counted_by to prevent the flexible array member's element type from including a flexible array member itself such as: struct foo { int count; char buf[]; }; struct bar { int count; struct foo data[] __counted_by(count); }; because the size of data cannot be calculated with the standard array size formula: sizeof(struct foo) * count This restriction was downgraded to a warning but due to CONFIG_WERROR, it can still break the build. The application of __counted_by on the ports member of 'struct mxser_board' triggers this restriction, resulting in: drivers/tty/mxser.c:291:2: error: 'counted_by' should not be applied to an array with element of unknown size because 'struct mxser_port' is a struct type with a flexible array member. This will be an error in a future compiler version [-Werror,-Wbounds-safety-counted-by-elt-type-unknown-size] 291 | struct mxser_port ports[] __counted_by(nports); | ^~~~~~~~~~~~~~~~~~~~~~~~~ 1 error generated. Remove this use of __counted_by to fix the warning/error. However, rather than remove it altogether, leave it commented, as it may be possible to support this in future compiler releases. Cc: stable(a)vger.kernel.org Closes: https://github.com/ClangBuiltLinux/linux/issues/2026 Fixes: f34907ecca71 ("mxser: Annotate struct mxser_board with __counted_by") Signed-off-by: Nathan Chancellor <nathan(a)kernel.org> --- drivers/tty/mxser.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c index 458bb1280ebf..5b97e420a95f 100644 --- a/drivers/tty/mxser.c +++ b/drivers/tty/mxser.c @@ -288,7 +288,7 @@ struct mxser_board { enum mxser_must_hwid must_hwid; speed_t max_baud; - struct mxser_port ports[] __counted_by(nports); + struct mxser_port ports[] /* __counted_by(nports) */; }; static DECLARE_BITMAP(mxser_boards, MXSER_BOARDS); --- base-commit: 1613e604df0cd359cf2a7fbd9be7a0bcfacfabd0 change-id: 20240529-drop-counted-by-ports-mxser-board-ed2a66f1a6e2 Best regards, -- Nathan Chancellor <nathan(a)kernel.org>

6 months

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[PATCH v2] ata: libata-core: Add ATA_HORKAGE_NOLPM for all Crucial BX SSD1 models

by Niklas Cassel

We got another report that CT1000BX500SSD1 does not work with LPM. If you look in libata-core.c, we have six different Crucial devices that are marked with ATA_HORKAGE_NOLPM. This model would have been the seventh. (This quirk is used on Crucial models starting with both CT* and Crucial_CT*) It is obvious that this vendor does not have a great history of supporting LPM properly, therefore, add the ATA_HORKAGE_NOLPM quirk for all Crucial BX SSD1 models. Fixes: 7627a0edef54 ("ata: ahci: Drop low power policy board type") Cc: stable(a)vger.kernel.org Reported-by: Alessandro Maggio <alex.tkd.alex(a)gmail.com> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218832 Reviewed-by: Damien Le Moal <dlemoal(a)kernel.org> Signed-off-by: Niklas Cassel <cassel(a)kernel.org> --- Changes since v1: -Picked up tags. -Use real name in Reported-by tag. drivers/ata/libata-core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index e1bf8a19b3c8..efb5195da60c 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -4137,8 +4137,7 @@ static const struct ata_blacklist_entry ata_device_blacklist [] = { { "PIONEER BD-RW BDR-205", NULL, ATA_HORKAGE_NOLPM }, /* Crucial devices with broken LPM support */ - { "CT500BX100SSD1", NULL, ATA_HORKAGE_NOLPM }, - { "CT240BX500SSD1", NULL, ATA_HORKAGE_NOLPM }, + { "CT*0BX*00SSD1", NULL, ATA_HORKAGE_NOLPM }, /* 512GB MX100 with MU01 firmware has both queued TRIM and LPM issues */ { "Crucial_CT512MX100*", "MU01", ATA_HORKAGE_NO_NCQ_TRIM | -- 2.45.2

6 months

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CONFIG_LEGACY_TIOCSTI support in stable branches

by Vitaly Chikunov

Sasha, Greg, Can you please backport CONFIG_LEGACY_TIOCSTI support into stable kernels? This, perhaps, would include there mainline commits: 83efeeeb3d04b22aaed1df99bc70a48fe9d22c4d tty: Allow TIOCSTI to be disabled 5c30f3e4a6e67c88c979ad30554bf4ef9b24fbd0 tty: Move TIOCSTI toggle variable before kerndoc b2ea273a477cd6e83daedbfa1981cd1a7468f73a tty: Fix typo in LEGACY_TIOCSTI Kconfig description 690c8b804ad2eafbd35da5d3c95ad325ca7d5061 TIOCSTI: always enable for CAP_SYS_ADMIN 3f29d9ee323ae5cda59d144d1f8b0b10ea065be0 TIOCSTI: Document CAP_SYS_ADMIN behaviour in Kconfig 8d1b43f6a6df7bcea20982ad376a000d90906b42 tty: Restrict access to TIOCLINUX' copy-and-paste subcommands Thanks,

6 months

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[PATCH v1] selftests/harness: Fix tests timeout and race condition

by Mickaël Salaün

We cannot use CLONE_VFORK because we also need to wait for the timeout signal. Restore tests timeout by using the original fork() call in __run_test() but also in __TEST_F_IMPL(). Also fix a race condition when waiting for the test child process. Because test metadata are shared between test processes, only the parent process must set the test PID (child). Otherwise, t->pid may be set to zero, leading to inconsistent error cases: # RUN layout1.rule_on_mountpoint ... # rule_on_mountpoint: Test ended in some other way [127] # OK layout1.rule_on_mountpoint ok 20 layout1.rule_on_mountpoint As safeguards, initialize the "status" variable with a valid exit code, and handle unknown test exits as errors. The use of fork() introduces a new race condition in landlock/fs_test.c which seems to be specific to hostfs bind mounts, but I haven't found the root cause and it's difficult to trigger. I'll try to fix it with another patch. Cc: Christian Brauner <brauner(a)kernel.org> Cc: Günther Noack <gnoack(a)google.com> Cc: Jakub Kicinski <kuba(a)kernel.org> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Brown <broonie(a)kernel.org> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Will Drewry <wad(a)chromium.org> Cc: stable(a)vger.kernel.org Closes: https://lore.kernel.org/r/9341d4db-5e21-418c-bf9e-9ae2da7877e1@sirena.org.uk Fixes: a86f18903db9 ("selftests/harness: Fix interleaved scheduling leading to race conditions") Fixes: 24cf65a62266 ("selftests/harness: Share _metadata between forked processes") Signed-off-by: Mickaël Salaün <mic(a)digikod.net> Link: https://lore.kernel.org/r/20240621180605.834676-1-mic@digikod.net --- tools/testing/selftests/kselftest_harness.h | 43 ++++++++++++--------- 1 file changed, 24 insertions(+), 19 deletions(-) diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h index b634969cbb6f..40723a6a083f 100644 --- a/tools/testing/selftests/kselftest_harness.h +++ b/tools/testing/selftests/kselftest_harness.h @@ -66,8 +66,6 @@ #include <sys/wait.h> #include <unistd.h> #include <setjmp.h> -#include <syscall.h> -#include <linux/sched.h> #include "kselftest.h" @@ -82,17 +80,6 @@ # define TH_LOG_ENABLED 1 #endif -/* Wait for the child process to end but without sharing memory mapping. */ -static inline pid_t clone3_vfork(void) -{ - struct clone_args args = { - .flags = CLONE_VFORK, - .exit_signal = SIGCHLD, - }; - - return syscall(__NR_clone3, &args, sizeof(args)); -} - /** * TH_LOG() * @@ -437,7 +424,7 @@ static inline pid_t clone3_vfork(void) } \ if (setjmp(_metadata->env) == 0) { \ /* _metadata and potentially self are shared with all forks. */ \ - child = clone3_vfork(); \ + child = fork(); \ if (child == 0) { \ fixture_name##_setup(_metadata, self, variant->data); \ /* Let setup failure terminate early. */ \ @@ -1016,7 +1003,14 @@ void __wait_for_test(struct __test_metadata *t) .sa_flags = SA_SIGINFO, }; struct sigaction saved_action; - int status; + /* + * Sets status so that WIFEXITED(status) returns true and + * WEXITSTATUS(status) returns KSFT_FAIL. This safe default value + * should never be evaluated because of the waitpid(2) check and + * SIGALRM handling. + */ + int status = KSFT_FAIL << 8; + int child; if (sigaction(SIGALRM, &action, &saved_action)) { t->exit_code = KSFT_FAIL; @@ -1028,7 +1022,15 @@ void __wait_for_test(struct __test_metadata *t) __active_test = t; t->timed_out = false; alarm(t->timeout); - waitpid(t->pid, &status, 0); + child = waitpid(t->pid, &status, 0); + if (child == -1 && errno != EINTR) { + t->exit_code = KSFT_FAIL; + fprintf(TH_LOG_STREAM, + "# %s: Failed to wait for PID %d (errno: %d)\n", + t->name, t->pid, errno); + return; + } + alarm(0); if (sigaction(SIGALRM, &saved_action, NULL)) { t->exit_code = KSFT_FAIL; @@ -1083,6 +1085,7 @@ void __wait_for_test(struct __test_metadata *t) WTERMSIG(status)); } } else { + t->exit_code = KSFT_FAIL; fprintf(TH_LOG_STREAM, "# %s: Test ended in some other way [%u]\n", t->name, @@ -1218,6 +1221,7 @@ void __run_test(struct __fixture_metadata *f, struct __test_xfail *xfail; char test_name[1024]; const char *diagnostic; + int child; /* reset test struct */ t->exit_code = KSFT_PASS; @@ -1236,15 +1240,16 @@ void __run_test(struct __fixture_metadata *f, fflush(stdout); fflush(stderr); - t->pid = clone3_vfork(); - if (t->pid < 0) { + child = fork(); + if (child < 0) { ksft_print_msg("ERROR SPAWNING TEST CHILD\n"); t->exit_code = KSFT_FAIL; - } else if (t->pid == 0) { + } else if (child == 0) { setpgrp(); t->fn(t, variant); _exit(t->exit_code); } else { + t->pid = child; __wait_for_test(t); } ksft_print_msg(" %4s %s\n", base-commit: 83a7eefedc9b56fe7bfeff13b6c7356688ffa670 -- 2.45.2

6 months

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[PATCH 4/4] nvmem: core: limit cell sysfs permissions to main attribute ones

by srinivas.kandagatla＠linaro.org

From: Thomas Weißschuh <linux(a)weissschuh.net> The cell sysfs attribute should not provide more access to the nvmem data than the main attribute itself. For example if nvme_config::root_only was set, the cell attribute would still provide read access to everybody. Mask out permissions not available on the main attribute. Fixes: 0331c611949f ("nvmem: core: Expose cells through sysfs") Cc: stable(a)vger.kernel.org Signed-off-by: Thomas Weißschuh <linux(a)weissschuh.net> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla(a)linaro.org> --- drivers/nvmem/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 1285300ed239..f8dd7eb40fbe 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -462,7 +462,7 @@ static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem) "%s@%x,%x", entry->name, entry->offset, entry->bit_offset); - attrs[i].attr.mode = 0444; + attrs[i].attr.mode = 0444 & nvmem_bin_attr_get_umode(nvmem); attrs[i].size = entry->bytes; attrs[i].read = &nvmem_cell_attr_read; attrs[i].private = entry; -- 2.25.1

6 months

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