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stable-rc/queue/5.4 build: 9 builds: 0 failed, 9 passed, 3 warnings (v5.4.77-105-gc72d10024c02)

by kernelci.org bot

stable-rc/queue/5.4 build: 9 builds: 0 failed, 9 passed, 3 warnings (v5.4.77-105-gc72d10024c02) Full Build Summary: https://kernelci.org/build/stable-rc/branch/queue%2F5.4/kernel/v5.4.77-105-… Tree: stable-rc Branch: queue/5.4 Git Describe: v5.4.77-105-gc72d10024c02 Git Commit: c72d10024c02c6cf7bf5684ecc1d1ab2b3ef7908 Git URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git Built: 3 unique architectures Warnings Detected: arm: s5pv210_defconfig (gcc-8): 1 warning sama5_defconfig (gcc-8): 1 warning mips: x86_64: tinyconfig (gcc-8): 1 warning Warnings summary: 2 WARNING: "return_address" [vmlinux] is a static EXPORT_SYMBOL_GPL 1 .config:1156:warning: override: UNWINDER_GUESS changes choice state ================================================================================ Detailed per-defconfig build reports: -------------------------------------------------------------------------------- aspeed_g4_defconfig (arm, gcc-8) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- bmips_be_defconfig (mips, gcc-8) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- malta_defconfig (mips, gcc-8) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- mips_paravirt_defconfig (mips, gcc-8) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- pic32mzda_defconfig (mips, gcc-8) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- pistachio_defconfig (mips, gcc-8) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- s5pv210_defconfig (arm, gcc-8) — PASS, 0 errors, 1 warning, 0 section mismatches Warnings: WARNING: "return_address" [vmlinux] is a static EXPORT_SYMBOL_GPL -------------------------------------------------------------------------------- sama5_defconfig (arm, gcc-8) — PASS, 0 errors, 1 warning, 0 section mismatches Warnings: WARNING: "return_address" [vmlinux] is a static EXPORT_SYMBOL_GPL -------------------------------------------------------------------------------- tinyconfig (x86_64, gcc-8) — PASS, 0 errors, 1 warning, 0 section mismatches Warnings: .config:1156:warning: override: UNWINDER_GUESS changes choice state --- For more info write to <info(a)kernelci.org>

4 years, 11 months

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[PATCH] drm/i915: Handle max_bpc==16

by Ville Syrjala

From: Ville Syrjälä <ville.syrjala(a)linux.intel.com> EDID can declare the maximum supported bpc up to 16, and apparently there are displays that do so. Currently we assume 12 bpc is tha max. Fix the assumption and toss in a MISSING_CASE() for any other value we don't expect to see. This fixes modesets with a display with EDID max bpc > 12. Previously any modeset would just silently fail on platforms that didn't otherwise limit this via the max_bpc property. In particular we don't add the max_bpc property to HDMI ports on gmch platforms, and thus we would see the raw max_bpc coming from the EDID. I suppose we could already adjust this to also allow 16bpc, but seeing as no current platform supports that there is little point. Cc: stable(a)vger.kernel.org Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2632 Signed-off-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com> --- drivers/gpu/drm/i915/display/intel_display.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 2729c852c668..2a6eb1ca9c8e 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -13060,10 +13060,11 @@ compute_sink_pipe_bpp(const struct drm_connector_state *conn_state, case 10 ... 11: bpp = 10 * 3; break; - case 12: + case 12 ... 16: bpp = 12 * 3; break; default: + MISSING_CASE(conn_state->max_bpc); return -EINVAL; } -- 2.26.2

4 years, 11 months

2
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FAILED: patch "[PATCH] reboot: fix overflow parsing reboot cpu number" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From df5b0ab3e08a156701b537809914b339b0daa526 Mon Sep 17 00:00:00 2001 From: Matteo Croce <mcroce(a)microsoft.com> Date: Fri, 13 Nov 2020 22:52:07 -0800 Subject: [PATCH] reboot: fix overflow parsing reboot cpu number Limit the CPU number to num_possible_cpus(), because setting it to a value lower than INT_MAX but higher than NR_CPUS produces the following error on reboot and shutdown: BUG: unable to handle page fault for address: ffffffff90ab1bb0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1c09067 P4D 1c09067 PUD 1c0a063 PMD 0 Oops: 0000 [#1] SMP CPU: 1 PID: 1 Comm: systemd-shutdow Not tainted 5.9.0-rc8-kvm #110 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 RIP: 0010:migrate_to_reboot_cpu+0xe/0x60 Code: ea ea 00 48 89 fa 48 c7 c7 30 57 f1 81 e9 fa ef ff ff 66 2e 0f 1f 84 00 00 00 00 00 53 8b 1d d5 ea ea 00 e8 14 33 fe ff 89 da <48> 0f a3 15 ea fc bd 00 48 89 d0 73 29 89 c2 c1 e8 06 65 48 8b 3c RSP: 0018:ffffc90000013e08 EFLAGS: 00010246 RAX: ffff88801f0a0000 RBX: 0000000077359400 RCX: 0000000000000000 RDX: 0000000077359400 RSI: 0000000000000002 RDI: ffffffff81c199e0 RBP: ffffffff81c1e3c0 R08: ffff88801f41f000 R09: ffffffff81c1e348 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 00007f32bedf8830 R14: 00000000fee1dead R15: 0000000000000000 FS: 00007f32bedf8980(0000) GS:ffff88801f480000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffff90ab1bb0 CR3: 000000001d057000 CR4: 00000000000006a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __do_sys_reboot.cold+0x34/0x5b do_syscall_64+0x2d/0x40 Fixes: 1b3a5d02ee07 ("reboot: move arch/x86 reboot= handling to generic kernel") Signed-off-by: Matteo Croce <mcroce(a)microsoft.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Cc: Arnd Bergmann <arnd(a)arndb.de> Cc: Fabian Frederick <fabf(a)skynet.be> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Guenter Roeck <linux(a)roeck-us.net> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Pavel Tatashin <pasha.tatashin(a)soleen.com> Cc: Petr Mladek <pmladek(a)suse.com> Cc: Robin Holt <robinmholt(a)gmail.com> Cc: <stable(a)vger.kernel.org> Link: https://lkml.kernel.org/r/20201103214025.116799-3-mcroce@linux.microsoft.com Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> diff --git a/kernel/reboot.c b/kernel/reboot.c index 8fbba433725e..af6f23d8bea1 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -558,6 +558,13 @@ static int __init reboot_setup(char *str) reboot_cpu = simple_strtoul(str+3, NULL, 0); else *mode = REBOOT_SOFT; + if (reboot_cpu >= num_possible_cpus()) { + pr_err("Ignoring the CPU number in reboot= option. " + "CPU %d exceeds possible cpu number %d\n", + reboot_cpu, num_possible_cpus()); + reboot_cpu = 0; + break; + } break; case 'g':

4 years, 11 months

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[merged] ocfs2-initialize-ip_next_orphan.patch removed from -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: ocfs2: initialize ip_next_orphan has been removed from the -mm tree. Its filename was ocfs2-initialize-ip_next_orphan.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Wengang Wang <wen.gang.wang(a)oracle.com> Subject: ocfs2: initialize ip_next_orphan Though problem if found on a lower 4.1.12 kernel, I think upstream has same issue. In one node in the cluster, there is the following callback trace: # cat /proc/21473/stack [<ffffffffc09a2f06>] __ocfs2_cluster_lock.isra.36+0x336/0x9e0 [ocfs2] [<ffffffffc09a4481>] ocfs2_inode_lock_full_nested+0x121/0x520 [ocfs2] [<ffffffffc09b2ce2>] ocfs2_evict_inode+0x152/0x820 [ocfs2] [<ffffffff8122b36e>] evict+0xae/0x1a0 [<ffffffff8122bd26>] iput+0x1c6/0x230 [<ffffffffc09b60ed>] ocfs2_orphan_filldir+0x5d/0x100 [ocfs2] [<ffffffffc0992ae0>] ocfs2_dir_foreach_blk+0x490/0x4f0 [ocfs2] [<ffffffffc099a1e9>] ocfs2_dir_foreach+0x29/0x30 [ocfs2] [<ffffffffc09b7716>] ocfs2_recover_orphans+0x1b6/0x9a0 [ocfs2] [<ffffffffc09b9b4e>] ocfs2_complete_recovery+0x1de/0x5c0 [ocfs2] [<ffffffff810a1399>] process_one_work+0x169/0x4a0 [<ffffffff810a1bcb>] worker_thread+0x5b/0x560 [<ffffffff810a7a2b>] kthread+0xcb/0xf0 [<ffffffff816f5d21>] ret_from_fork+0x61/0x90 [<ffffffffffffffff>] 0xffffffffffffffff The above stack is not reasonable, the final iput shouldn't happen in ocfs2_orphan_filldir() function. Looking at the code, 2067 /* Skip inodes which are already added to recover list, since dio may 2068 * happen concurrently with unlink/rename */ 2069 if (OCFS2_I(iter)->ip_next_orphan) { 2070 iput(iter); 2071 return 0; 2072 } 2073 The logic thinks the inode is already in recover list on seeing ip_next_orphan is non-NULL, so it skip this inode after dropping a reference which incremented in ocfs2_iget(). While, if the inode is already in recover list, it should have another reference and the iput() at line 2070 should not be the final iput (dropping the last reference). So I don't think the inode is really in the recover list (no vmcore to confirm). Note that ocfs2_queue_orphans(), though not shown up in the call back trace, is holding cluster lock on the orphan directory when looking up for unlinked inodes. The on disk inode eviction could involve a lot of IOs which may need long time to finish. That means this node could hold the cluster lock for very long time, that can lead to the lock requests (from other nodes) to the orhpan directory hang for long time. Looking at more on ip_next_orphan, I found it's not initialized when allocating a new ocfs2_inode_info structure. This causes te reflink operations from some nodes hang for very long time waiting for the cluster lock on the orphan directory. Fix: initialize ip_next_orphan as NULL. Link: https://lkml.kernel.org/r/20201109171746.27884-1-wen.gang.wang@oracle.com Signed-off-by: Wengang Wang <wen.gang.wang(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: Gang He <ghe(a)suse.com> 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/super.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/ocfs2/super.c~ocfs2-initialize-ip_next_orphan +++ a/fs/ocfs2/super.c @@ -1713,6 +1713,7 @@ static void ocfs2_inode_init_once(void * oi->ip_blkno = 0ULL; oi->ip_clusters = 0; + oi->ip_next_orphan = NULL; ocfs2_resv_init_once(&oi->ip_la_data_resv); _ Patches currently in -mm which might be from wen.gang.wang(a)oracle.com are

4 years, 11 months

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[merged] hugetlbfs-fix-anon-huge-page-migration-race.patch removed from -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: hugetlbfs: fix anon huge page migration race has been removed from the -mm tree. Its filename was hugetlbfs-fix-anon-huge-page-migration-race.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Mike Kravetz <mike.kravetz(a)oracle.com> Subject: hugetlbfs: fix anon huge page migration race Qian Cai reported the following BUG in [1] [ 6147.019063][T45242] LTP: starting move_pages12 [ 6147.475680][T64921] BUG: unable to handle page fault for address: ffffffffffffffe0 ... [ 6147.525866][T64921] RIP: 0010:anon_vma_interval_tree_iter_first+0xa2/0x170 avc_start_pgoff at mm/interval_tree.c:63 [ 6147.620914][T64921] Call Trace: [ 6147.624078][T64921] rmap_walk_anon+0x141/0xa30 rmap_walk_anon at mm/rmap.c:1864 [ 6147.628639][T64921] try_to_unmap+0x209/0x2d0 try_to_unmap at mm/rmap.c:1763 [ 6147.633026][T64921] ? rmap_walk_locked+0x140/0x140 [ 6147.637936][T64921] ? page_remove_rmap+0x1190/0x1190 [ 6147.643020][T64921] ? page_not_mapped+0x10/0x10 [ 6147.647668][T64921] ? page_get_anon_vma+0x290/0x290 [ 6147.652664][T64921] ? page_mapcount_is_zero+0x10/0x10 [ 6147.657838][T64921] ? hugetlb_page_mapping_lock_write+0x97/0x180 [ 6147.663972][T64921] migrate_pages+0x1005/0x1fb0 [ 6147.668617][T64921] ? remove_migration_pte+0xac0/0xac0 [ 6147.673875][T64921] move_pages_and_store_status.isra.47+0xd7/0x1a0 [ 6147.680181][T64921] ? migrate_pages+0x1fb0/0x1fb0 [ 6147.685002][T64921] __x64_sys_move_pages+0xa5c/0x1100 [ 6147.690176][T64921] ? trace_hardirqs_on+0x20/0x1b5 [ 6147.695084][T64921] ? move_pages_and_store_status.isra.47+0x1a0/0x1a0 [ 6147.701653][T64921] ? rcu_read_lock_sched_held+0xaa/0xd0 [ 6147.707088][T64921] ? switch_fpu_return+0x196/0x400 [ 6147.712083][T64921] ? lockdep_hardirqs_on_prepare+0x38c/0x550 [ 6147.717954][T64921] ? do_syscall_64+0x24/0x310 [ 6147.722513][T64921] do_syscall_64+0x5f/0x310 [ 6147.726897][T64921] ? trace_hardirqs_off+0x12/0x1a0 [ 6147.731894][T64921] ? asm_exc_page_fault+0x8/0x30 [ 6147.736714][T64921] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Hugh Dickens diagnosed this as a migration bug caused by code introduced to use i_mmap_rwsem for pmd sharing synchronization. Specifically, the routine unmap_and_move_huge_page() is always passing the TTU_RMAP_LOCKED flag to try_to_unmap() while holding i_mmap_rwsem. This is wrong for anon pages as the anon_vma_lock should be held in this case. Further analysis suggested that i_mmap_rwsem was not required to he held at all when calling try_to_unmap for anon pages as an anon page could never be part of a shared pmd mapping. Discussion also revealed that the hack in hugetlb_page_mapping_lock_write to drop page lock and acquire i_mmap_rwsem is wrong. There is no way to keep mapping valid while dropping page lock. This patch does the following: - Do not take i_mmap_rwsem and set TTU_RMAP_LOCKED for anon pages when calling try_to_unmap. - Remove the hacky code in hugetlb_page_mapping_lock_write. The routine will now simply do a 'trylock' while still holding the page lock. If the trylock fails, it will return NULL. This could impact the callers: - migration calling code will receive -EAGAIN and retry up to the hard coded limit (10). - memory error code will treat the page as BUSY. This will force killing (SIGKILL) instead of SIGBUS any mapping tasks. Do note that this change in behavior only happens when there is a race. None of the standard kernel testing suites actually hit this race, but it is possible. [1] https://lore.kernel.org/lkml/20200708012044.GC992@lca.pw/ [2] https://lore.kernel.org/linux-mm/alpine.LSU.2.11.2010071833100.2214@eggly.a… Link: https://lkml.kernel.org/r/20201105195058.78401-1-mike.kravetz@oracle.com Fixes: c0d0381ade79 ("hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization") Signed-off-by: Mike Kravetz <mike.kravetz(a)oracle.com> Reported-by: Qian Cai <cai(a)lca.pw> Suggested-by: Hugh Dickins <hughd(a)google.com> Acked-by: Naoya Horiguchi <naoya.horiguchi(a)nec.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/hugetlb.c | 90 ++---------------------------------------- mm/memory-failure.c | 36 +++++++--------- mm/migrate.c | 46 +++++++++++---------- mm/rmap.c | 5 -- 4 files changed, 48 insertions(+), 129 deletions(-) --- a/mm/hugetlb.c~hugetlbfs-fix-anon-huge-page-migration-race +++ a/mm/hugetlb.c @@ -1568,103 +1568,23 @@ int PageHeadHuge(struct page *page_head) } /* - * Find address_space associated with hugetlbfs page. - * Upon entry page is locked and page 'was' mapped although mapped state - * could change. If necessary, use anon_vma to find vma and associated - * address space. The returned mapping may be stale, but it can not be - * invalid as page lock (which is held) is required to destroy mapping. - */ -static struct address_space *_get_hugetlb_page_mapping(struct page *hpage) -{ - struct anon_vma *anon_vma; - pgoff_t pgoff_start, pgoff_end; - struct anon_vma_chain *avc; - struct address_space *mapping = page_mapping(hpage); - - /* Simple file based mapping */ - if (mapping) - return mapping; - - /* - * Even anonymous hugetlbfs mappings are associated with an - * underlying hugetlbfs file (see hugetlb_file_setup in mmap - * code). Find a vma associated with the anonymous vma, and - * use the file pointer to get address_space. - */ - anon_vma = page_lock_anon_vma_read(hpage); - if (!anon_vma) - return mapping; /* NULL */ - - /* Use first found vma */ - pgoff_start = page_to_pgoff(hpage); - pgoff_end = pgoff_start + pages_per_huge_page(page_hstate(hpage)) - 1; - anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, - pgoff_start, pgoff_end) { - struct vm_area_struct *vma = avc->vma; - - mapping = vma->vm_file->f_mapping; - break; - } - - anon_vma_unlock_read(anon_vma); - return mapping; -} - -/* * Find and lock address space (mapping) in write mode. * - * Upon entry, the page is locked which allows us to find the mapping - * even in the case of an anon page. However, locking order dictates - * the i_mmap_rwsem be acquired BEFORE the page lock. This is hugetlbfs - * specific. So, we first try to lock the sema while still holding the - * page lock. If this works, great! If not, then we need to drop the - * page lock and then acquire i_mmap_rwsem and reacquire page lock. Of - * course, need to revalidate state along the way. + * Upon entry, the page is locked which means that page_mapping() is + * stable. Due to locking order, we can only trylock_write. If we can + * not get the lock, simply return NULL to caller. */ struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage) { - struct address_space *mapping, *mapping2; + struct address_space *mapping = page_mapping(hpage); - mapping = _get_hugetlb_page_mapping(hpage); -retry: if (!mapping) return mapping; - /* - * If no contention, take lock and return - */ if (i_mmap_trylock_write(mapping)) return mapping; - /* - * Must drop page lock and wait on mapping sema. - * Note: Once page lock is dropped, mapping could become invalid. - * As a hack, increase map count until we lock page again. - */ - atomic_inc(&hpage->_mapcount); - unlock_page(hpage); - i_mmap_lock_write(mapping); - lock_page(hpage); - atomic_add_negative(-1, &hpage->_mapcount); - - /* verify page is still mapped */ - if (!page_mapped(hpage)) { - i_mmap_unlock_write(mapping); - return NULL; - } - - /* - * Get address space again and verify it is the same one - * we locked. If not, drop lock and retry. - */ - mapping2 = _get_hugetlb_page_mapping(hpage); - if (mapping2 != mapping) { - i_mmap_unlock_write(mapping); - mapping = mapping2; - goto retry; - } - - return mapping; + return NULL; } pgoff_t __basepage_index(struct page *page) --- a/mm/memory-failure.c~hugetlbfs-fix-anon-huge-page-migration-race +++ a/mm/memory-failure.c @@ -1057,27 +1057,25 @@ static bool hwpoison_user_mappings(struc if (!PageHuge(hpage)) { unmap_success = try_to_unmap(hpage, ttu); } else { - /* - * For hugetlb pages, try_to_unmap could potentially call - * huge_pmd_unshare. Because of this, take semaphore in - * write mode here and set TTU_RMAP_LOCKED to indicate we - * have taken the lock at this higer level. - * - * Note that the call to hugetlb_page_mapping_lock_write - * is necessary even if mapping is already set. It handles - * ugliness of potentially having to drop page lock to obtain - * i_mmap_rwsem. - */ - mapping = hugetlb_page_mapping_lock_write(hpage); - - if (mapping) { - unmap_success = try_to_unmap(hpage, + if (!PageAnon(hpage)) { + /* + * For hugetlb pages in shared mappings, try_to_unmap + * could potentially call huge_pmd_unshare. Because of + * this, take semaphore in write mode here and set + * TTU_RMAP_LOCKED to indicate we have taken the lock + * at this higer level. + */ + mapping = hugetlb_page_mapping_lock_write(hpage); + if (mapping) { + unmap_success = try_to_unmap(hpage, ttu|TTU_RMAP_LOCKED); - i_mmap_unlock_write(mapping); + i_mmap_unlock_write(mapping); + } else { + pr_info("Memory failure: %#lx: could not lock mapping for mapped huge page\n", pfn); + unmap_success = false; + } } else { - pr_info("Memory failure: %#lx: could not find mapping for mapped huge page\n", - pfn); - unmap_success = false; + unmap_success = try_to_unmap(hpage, ttu); } } if (!unmap_success) --- a/mm/migrate.c~hugetlbfs-fix-anon-huge-page-migration-race +++ a/mm/migrate.c @@ -1328,34 +1328,38 @@ static int unmap_and_move_huge_page(new_ goto put_anon; if (page_mapped(hpage)) { - /* - * try_to_unmap could potentially call huge_pmd_unshare. - * Because of this, take semaphore in write mode here and - * set TTU_RMAP_LOCKED to let lower levels know we have - * taken the lock. - */ - mapping = hugetlb_page_mapping_lock_write(hpage); - if (unlikely(!mapping)) - goto unlock_put_anon; - - try_to_unmap(hpage, - TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS| - TTU_RMAP_LOCKED); + bool mapping_locked = false; + enum ttu_flags ttu = TTU_MIGRATION|TTU_IGNORE_MLOCK| + TTU_IGNORE_ACCESS; + + if (!PageAnon(hpage)) { + /* + * In shared mappings, try_to_unmap could potentially + * call huge_pmd_unshare. Because of this, take + * semaphore in write mode here and set TTU_RMAP_LOCKED + * to let lower levels know we have taken the lock. + */ + mapping = hugetlb_page_mapping_lock_write(hpage); + if (unlikely(!mapping)) + goto unlock_put_anon; + + mapping_locked = true; + ttu |= TTU_RMAP_LOCKED; + } + + try_to_unmap(hpage, ttu); page_was_mapped = 1; - /* - * Leave mapping locked until after subsequent call to - * remove_migration_ptes() - */ + + if (mapping_locked) + i_mmap_unlock_write(mapping); } if (!page_mapped(hpage)) rc = move_to_new_page(new_hpage, hpage, mode); - if (page_was_mapped) { + if (page_was_mapped) remove_migration_ptes(hpage, - rc == MIGRATEPAGE_SUCCESS ? new_hpage : hpage, true); - i_mmap_unlock_write(mapping); - } + rc == MIGRATEPAGE_SUCCESS ? new_hpage : hpage, false); unlock_put_anon: unlock_page(new_hpage); --- a/mm/rmap.c~hugetlbfs-fix-anon-huge-page-migration-race +++ a/mm/rmap.c @@ -1413,9 +1413,6 @@ static bool try_to_unmap_one(struct page /* * If sharing is possible, start and end will be adjusted * accordingly. - * - * If called for a huge page, caller must hold i_mmap_rwsem - * in write mode as it is possible to call huge_pmd_unshare. */ adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end); @@ -1462,7 +1459,7 @@ static bool try_to_unmap_one(struct page subpage = page - page_to_pfn(page) + pte_pfn(*pvmw.pte); address = pvmw.address; - if (PageHuge(page)) { + if (PageHuge(page) && !PageAnon(page)) { /* * To call huge_pmd_unshare, i_mmap_rwsem must be * held in write mode. Caller needs to explicitly _ Patches currently in -mm which might be from mike.kravetz(a)oracle.com are

4 years, 11 months

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[merged] reboot-fix-overflow-parsing-reboot-cpu-number.patch removed from -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: reboot: fix overflow parsing reboot cpu number has been removed from the -mm tree. Its filename was reboot-fix-overflow-parsing-reboot-cpu-number.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Matteo Croce <mcroce(a)microsoft.com> Subject: reboot: fix overflow parsing reboot cpu number Limit the CPU number to num_possible_cpus(), because setting it to a value lower than INT_MAX but higher than NR_CPUS produces the following error on reboot and shutdown: BUG: unable to handle page fault for address: ffffffff90ab1bb0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1c09067 P4D 1c09067 PUD 1c0a063 PMD 0 Oops: 0000 [#1] SMP CPU: 1 PID: 1 Comm: systemd-shutdow Not tainted 5.9.0-rc8-kvm #110 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 RIP: 0010:migrate_to_reboot_cpu+0xe/0x60 Code: ea ea 00 48 89 fa 48 c7 c7 30 57 f1 81 e9 fa ef ff ff 66 2e 0f 1f 84 00 00 00 00 00 53 8b 1d d5 ea ea 00 e8 14 33 fe ff 89 da <48> 0f a3 15 ea fc bd 00 48 89 d0 73 29 89 c2 c1 e8 06 65 48 8b 3c RSP: 0018:ffffc90000013e08 EFLAGS: 00010246 RAX: ffff88801f0a0000 RBX: 0000000077359400 RCX: 0000000000000000 RDX: 0000000077359400 RSI: 0000000000000002 RDI: ffffffff81c199e0 RBP: ffffffff81c1e3c0 R08: ffff88801f41f000 R09: ffffffff81c1e348 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 00007f32bedf8830 R14: 00000000fee1dead R15: 0000000000000000 FS: 00007f32bedf8980(0000) GS:ffff88801f480000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffff90ab1bb0 CR3: 000000001d057000 CR4: 00000000000006a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __do_sys_reboot.cold+0x34/0x5b ? vfs_writev+0x92/0xc0 ? do_writev+0x52/0xd0 do_syscall_64+0x2d/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f32bfaaecd3 Code: 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 89 fa be 69 19 12 28 bf ad de e1 fe b8 a9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 89 81 0c 00 f7 d8 RSP: 002b:00007fff6265fb58 EFLAGS: 00000202 ORIG_RAX: 00000000000000a9 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f32bfaaecd3 RDX: 0000000001234567 RSI: 0000000028121969 RDI: 00000000fee1dead RBP: 0000000000000000 R08: 0000000000008020 R09: 00007fff6265ef60 R10: 00007f32bedf8830 R11: 0000000000000202 R12: 0000000000000000 R13: 0000557bba2c51c0 R14: 0000000000000000 R15: 00007fff6265fbc8 CR2: ffffffff90ab1bb0 ---[ end trace b813e80157136563 ]--- RIP: 0010:migrate_to_reboot_cpu+0xe/0x60 Code: ea ea 00 48 89 fa 48 c7 c7 30 57 f1 81 e9 fa ef ff ff 66 2e 0f 1f 84 00 00 00 00 00 53 8b 1d d5 ea ea 00 e8 14 33 fe ff 89 da <48> 0f a3 15 ea fc bd 00 48 89 d0 73 29 89 c2 c1 e8 06 65 48 8b 3c RSP: 0018:ffffc90000013e08 EFLAGS: 00010246 RAX: ffff88801f0a0000 RBX: 0000000077359400 RCX: 0000000000000000 RDX: 0000000077359400 RSI: 0000000000000002 RDI: ffffffff81c199e0 RBP: ffffffff81c1e3c0 R08: ffff88801f41f000 R09: ffffffff81c1e348 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 00007f32bedf8830 R14: 00000000fee1dead R15: 0000000000000000 FS: 00007f32bedf8980(0000) GS:ffff88801f480000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffff90ab1bb0 CR3: 000000001d057000 CR4: 00000000000006a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 Kernel Offset: disabled ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 ]--- Link: https://lkml.kernel.org/r/20201103214025.116799-3-mcroce@linux.microsoft.com Fixes: 1b3a5d02ee07 ("reboot: move arch/x86 reboot= handling to generic kernel") Signed-off-by: Matteo Croce <mcroce(a)microsoft.com> Cc: Arnd Bergmann <arnd(a)arndb.de> Cc: Fabian Frederick <fabf(a)skynet.be> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Guenter Roeck <linux(a)roeck-us.net> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Pavel Tatashin <pasha.tatashin(a)soleen.com> Cc: Petr Mladek <pmladek(a)suse.com> Cc: Robin Holt <robinmholt(a)gmail.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- kernel/reboot.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/kernel/reboot.c~reboot-fix-overflow-parsing-reboot-cpu-number +++ a/kernel/reboot.c @@ -558,6 +558,13 @@ static int __init reboot_setup(char *str reboot_cpu = simple_strtoul(str+3, NULL, 0); else *mode = REBOOT_SOFT; + if (reboot_cpu >= num_possible_cpus()) { + pr_err("Ignoring the CPU number in reboot= option. " + "CPU %d exceeds possible cpu number %d\n", + reboot_cpu, num_possible_cpus()); + reboot_cpu = 0; + break; + } break; case 'g': _ Patches currently in -mm which might be from mcroce(a)microsoft.com are reboot-refactor-and-comment-the-cpu-selection-code.patch reboot-allow-to-specify-reboot-mode-via-sysfs.patch reboot-remove-cf9_safe-from-allowed-types-and-rename-cf9_force.patch

4 years, 11 months

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[merged] revert-kernel-rebootc-convert-simple_strtoul-to-kstrtoint.patch removed from -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: Revert "kernel/reboot.c: convert simple_strtoul to kstrtoint" has been removed from the -mm tree. Its filename was revert-kernel-rebootc-convert-simple_strtoul-to-kstrtoint.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Matteo Croce <mcroce(a)microsoft.com> Subject: Revert "kernel/reboot.c: convert simple_strtoul to kstrtoint" Patch series "fix parsing of reboot= cmdline", v3. The parsing of the reboot= cmdline has two major errors: - a missing bound check can crash the system on reboot - parsing of the cpu number only works if specified last Fix both. This patch (of 2): This reverts commit 616feab753972b97. kstrtoint() and simple_strtoul() have a subtle difference which makes them non interchangeable: if a non digit character is found amid the parsing, the former will return an error, while the latter will just stop parsing, e.g. simple_strtoul("123xyx") = 123. The kernel cmdline reboot= argument allows to specify the CPU used for rebooting, with the syntax `s####` among the other flags, e.g. "reboot=warm,s31,force", so if this flag is not the last given, it's silently ignored as well as the subsequent ones. Link: https://lkml.kernel.org/r/20201103214025.116799-2-mcroce@linux.microsoft.com Fixes: 616feab75397 ("kernel/reboot.c: convert simple_strtoul to kstrtoint") Signed-off-by: Matteo Croce <mcroce(a)microsoft.com> Cc: Guenter Roeck <linux(a)roeck-us.net> Cc: Petr Mladek <pmladek(a)suse.com> Cc: Arnd Bergmann <arnd(a)arndb.de> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Kees Cook <keescook(a)chromium.org> Cc: Pavel Tatashin <pasha.tatashin(a)soleen.com> Cc: Robin Holt <robinmholt(a)gmail.com> Cc: Fabian Frederick <fabf(a)skynet.be> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- kernel/reboot.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) --- a/kernel/reboot.c~revert-kernel-rebootc-convert-simple_strtoul-to-kstrtoint +++ a/kernel/reboot.c @@ -551,22 +551,15 @@ static int __init reboot_setup(char *str break; case 's': - { - int rc; - - if (isdigit(*(str+1))) { - rc = kstrtoint(str+1, 0, &reboot_cpu); - if (rc) - return rc; - } else if (str[1] == 'm' && str[2] == 'p' && - isdigit(*(str+3))) { - rc = kstrtoint(str+3, 0, &reboot_cpu); - if (rc) - return rc; - } else + if (isdigit(*(str+1))) + reboot_cpu = simple_strtoul(str+1, NULL, 0); + else if (str[1] == 'm' && str[2] == 'p' && + isdigit(*(str+3))) + reboot_cpu = simple_strtoul(str+3, NULL, 0); + else *mode = REBOOT_SOFT; break; - } + case 'g': *mode = REBOOT_GPIO; break; _ Patches currently in -mm which might be from mcroce(a)microsoft.com are reboot-refactor-and-comment-the-cpu-selection-code.patch reboot-allow-to-specify-reboot-mode-via-sysfs.patch reboot-remove-cf9_safe-from-allowed-types-and-rename-cf9_force.patch

4 years, 11 months

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[merged] compilerh-fix-barrier_data-on-clang.patch removed from -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: compiler.h: fix barrier_data() on clang has been removed from the -mm tree. Its filename was compilerh-fix-barrier_data-on-clang.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Arvind Sankar <nivedita(a)alum.mit.edu> Subject: compiler.h: fix barrier_data() on clang Commit 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive") neglected to copy barrier_data() from compiler-gcc.h into compiler-clang.h. The definition in compiler-gcc.h was really to work around clang's more aggressive optimization, so this broke barrier_data() on clang, and consequently memzero_explicit() as well. For example, this results in at least the memzero_explicit() call in lib/crypto/sha256.c:sha256_transform() being optimized away by clang. Fix this by moving the definition of barrier_data() into compiler.h. Also move the gcc/clang definition of barrier() into compiler.h, __memory_barrier() is icc-specific (and barrier() is already defined using it in compiler-intel.h) and doesn't belong in compiler.h. [rdunlap(a)infradead.org: fix ALPHA builds when SMP is not enabled] Link: https://lkml.kernel.org/r/20201101231835.4589-1-rdunlap@infradead.org Link: https://lkml.kernel.org/r/20201014212631.207844-1-nivedita@alum.mit.edu Fixes: 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive") Signed-off-by: Arvind Sankar <nivedita(a)alum.mit.edu> Signed-off-by: Randy Dunlap <rdunlap(a)infradead.org> Reviewed-by: Nick Desaulniers <ndesaulniers(a)google.com> Tested-by: Nick Desaulniers <ndesaulniers(a)google.com> Reviewed-by: Kees Cook <keescook(a)chromium.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/asm-generic/barrier.h | 1 + include/linux/compiler-clang.h | 6 ------ include/linux/compiler-gcc.h | 19 ------------------- include/linux/compiler.h | 18 ++++++++++++++++-- 4 files changed, 17 insertions(+), 27 deletions(-) --- a/include/asm-generic/barrier.h~compilerh-fix-barrier_data-on-clang +++ a/include/asm-generic/barrier.h @@ -13,6 +13,7 @@ #ifndef __ASSEMBLY__ +#include <linux/compiler.h> #include <asm/rwonce.h> #ifndef nop --- a/include/linux/compiler-clang.h~compilerh-fix-barrier_data-on-clang +++ a/include/linux/compiler-clang.h @@ -60,12 +60,6 @@ #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 #endif -/* The following are for compatibility with GCC, from compiler-gcc.h, - * and may be redefined here because they should not be shared with other - * compilers, like ICC. - */ -#define barrier() __asm__ __volatile__("" : : : "memory") - #if __has_feature(shadow_call_stack) # define __noscs __attribute__((__no_sanitize__("shadow-call-stack"))) #endif --- a/include/linux/compiler-gcc.h~compilerh-fix-barrier_data-on-clang +++ a/include/linux/compiler-gcc.h @@ -15,25 +15,6 @@ # error Sorry, your version of GCC is too old - please use 4.9 or newer. #endif -/* Optimization barrier */ - -/* The "volatile" is due to gcc bugs */ -#define barrier() __asm__ __volatile__("": : :"memory") -/* - * This version is i.e. to prevent dead stores elimination on @ptr - * where gcc and llvm may behave differently when otherwise using - * normal barrier(): while gcc behavior gets along with a normal - * barrier(), llvm needs an explicit input variable to be assumed - * clobbered. The issue is as follows: while the inline asm might - * access any memory it wants, the compiler could have fit all of - * @ptr into memory registers instead, and since @ptr never escaped - * from that, it proved that the inline asm wasn't touching any of - * it. This version works well with both compilers, i.e. we're telling - * the compiler that the inline asm absolutely may see the contents - * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495 - */ -#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory") - /* * This macro obfuscates arithmetic on a variable address so that gcc * shouldn't recognize the original var, and make assumptions about it. --- a/include/linux/compiler.h~compilerh-fix-barrier_data-on-clang +++ a/include/linux/compiler.h @@ -80,11 +80,25 @@ void ftrace_likely_update(struct ftrace_ /* Optimization barrier */ #ifndef barrier -# define barrier() __memory_barrier() +/* The "volatile" is due to gcc bugs */ +# define barrier() __asm__ __volatile__("": : :"memory") #endif #ifndef barrier_data -# define barrier_data(ptr) barrier() +/* + * This version is i.e. to prevent dead stores elimination on @ptr + * where gcc and llvm may behave differently when otherwise using + * normal barrier(): while gcc behavior gets along with a normal + * barrier(), llvm needs an explicit input variable to be assumed + * clobbered. The issue is as follows: while the inline asm might + * access any memory it wants, the compiler could have fit all of + * @ptr into memory registers instead, and since @ptr never escaped + * from that, it proved that the inline asm wasn't touching any of + * it. This version works well with both compilers, i.e. we're telling + * the compiler that the inline asm absolutely may see the contents + * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495 + */ +# define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory") #endif /* workaround for GCC PR82365 if needed */ _ Patches currently in -mm which might be from nivedita(a)alum.mit.edu are

4 years, 11 months

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[merged] mm-gup-use-unpin_user_pages-in-__gup_longterm_locked.patch removed from -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/gup: use unpin_user_pages() in __gup_longterm_locked() has been removed from the -mm tree. Its filename was mm-gup-use-unpin_user_pages-in-__gup_longterm_locked.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Jason Gunthorpe <jgg(a)nvidia.com> Subject: mm/gup: use unpin_user_pages() in __gup_longterm_locked() When FOLL_PIN is passed to __get_user_pages() the page list must be put back using unpin_user_pages() otherwise the page pin reference persists in a corrupted state. There are two places in the unwind of __gup_longterm_locked() that put the pages back without checking. Normally on error this function would return the partial page list making this the caller's responsibility, but in these two cases the caller is not allowed to see these pages at all. Link: https://lkml.kernel.org/r/0-v2-3ae7d9d162e2+2a7-gup_cma_fix_jgg@nvidia.com Fixes: 3faa52c03f44 ("mm/gup: track FOLL_PIN pages") Signed-off-by: Jason Gunthorpe <jgg(a)nvidia.com> Reported-by: Ira Weiny <ira.weiny(a)intel.com> Reviewed-by: Ira Weiny <ira.weiny(a)intel.com> Reviewed-by: John Hubbard <jhubbard(a)nvidia.com> Cc: Aneesh Kumar K.V <aneesh.kumar(a)linux.ibm.com> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/gup.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) --- a/mm/gup.c~mm-gup-use-unpin_user_pages-in-__gup_longterm_locked +++ a/mm/gup.c @@ -1647,8 +1647,11 @@ check_again: /* * drop the above get_user_pages reference. */ - for (i = 0; i < nr_pages; i++) - put_page(pages[i]); + if (gup_flags & FOLL_PIN) + unpin_user_pages(pages, nr_pages); + else + for (i = 0; i < nr_pages; i++) + put_page(pages[i]); if (migrate_pages(&cma_page_list, alloc_migration_target, NULL, (unsigned long)&mtc, MIGRATE_SYNC, MR_CONTIG_RANGE)) { @@ -1728,8 +1731,11 @@ static long __gup_longterm_locked(struct goto out; if (check_dax_vmas(vmas_tmp, rc)) { - for (i = 0; i < rc; i++) - put_page(pages[i]); + if (gup_flags & FOLL_PIN) + unpin_user_pages(pages, rc); + else + for (i = 0; i < rc; i++) + put_page(pages[i]); rc = -EOPNOTSUPP; goto out; } _ Patches currently in -mm which might be from jgg(a)nvidia.com are mm-reorganize-internal_get_user_pages_fast.patch mm-prevent-gup_fast-from-racing-with-cow-during-fork.patch

4 years, 11 months

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[merged] mm-slub-fix-panic-in-slab_alloc_node.patch removed from -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/slub: fix panic in slab_alloc_node() has been removed from the -mm tree. Its filename was mm-slub-fix-panic-in-slab_alloc_node.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Laurent Dufour <ldufour(a)linux.ibm.com> Subject: mm/slub: fix panic in slab_alloc_node() While doing memory hot-unplug operation on a PowerPC VM running 1024 CPUs with 11TB of ram, I hit the following panic: BUG: Kernel NULL pointer dereference on read at 0x00000007 Faulting instruction address: 0xc000000000456048 Oops: Kernel access of bad area, sig: 11 [#2] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS= 2048 NUMA pSeries Modules linked in: rpadlpar_io rpaphp CPU: 160 PID: 1 Comm: systemd Tainted: G D 5.9.0 #1 NIP: c000000000456048 LR: c000000000455fd4 CTR: c00000000047b350 REGS: c00006028d1b77a0 TRAP: 0300 Tainted: G D (5.9.0) MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 24004228 XER: 00000000 CFAR: c00000000000f1b0 DAR: 0000000000000007 DSISR: 40000000 IRQMASK: 0 GPR00: c000000000455fd4 c00006028d1b7a30 c000000001bec800 0000000000000000 GPR04: 0000000000000dc0 0000000000000000 00000000000374ef c00007c53df99320 GPR08: 000007c53c980000 0000000000000000 000007c53c980000 0000000000000000 GPR12: 0000000000004400 c00000001e8e4400 0000000000000000 0000000000000f6a GPR16: 0000000000000000 c000000001c25930 c000000001d62528 00000000000000c1 GPR20: c000000001d62538 c00006be469e9000 0000000fffffffe0 c0000000003c0ff8 GPR24: 0000000000000018 0000000000000000 0000000000000dc0 0000000000000000 GPR28: c00007c513755700 c000000001c236a4 c00007bc4001f800 0000000000000001 NIP [c000000000456048] __kmalloc_node+0x108/0x790 LR [c000000000455fd4] __kmalloc_node+0x94/0x790 Call Trace: [c00006028d1b7a30] [c00007c51af92000] 0xc00007c51af92000 (unreliable) [c00006028d1b7aa0] [c0000000003c0ff8] kvmalloc_node+0x58/0x110 [c00006028d1b7ae0] [c00000000047b45c] mem_cgroup_css_online+0x10c/0x270 [c00006028d1b7b30] [c000000000241fd8] online_css+0x48/0xd0 [c00006028d1b7b60] [c00000000024af14] cgroup_apply_control_enable+0x2c4/0x470 [c00006028d1b7c40] [c00000000024e838] cgroup_mkdir+0x408/0x5f0 [c00006028d1b7cb0] [c0000000005a4ef0] kernfs_iop_mkdir+0x90/0x100 [c00006028d1b7cf0] [c0000000004b8168] vfs_mkdir+0x138/0x250 [c00006028d1b7d40] [c0000000004baf04] do_mkdirat+0x154/0x1c0 [c00006028d1b7dc0] [c000000000032b38] system_call_exception+0xf8/0x200 [c00006028d1b7e20] [c00000000000c740] system_call_common+0xf0/0x27c Instruction dump: e93e0000 e90d0030 39290008 7cc9402a e94d0030 e93e0000 7ce95214 7f89502a 2fbc0000 419e0018 41920230 e9270010 <89290007> 7f994800 419e0220 7ee6bb78 This pointing to the following code: mm/slub.c:2851 if (unlikely(!object || !node_match(page, node))) { c000000000456038: 00 00 bc 2f cmpdi cr7,r28,0 c00000000045603c: 18 00 9e 41 beq cr7,c000000000456054 <__kmalloc_node+0x114> node_match(): mm/slub.c:2491 if (node != NUMA_NO_NODE && page_to_nid(page) != node) c000000000456040: 30 02 92 41 beq cr4,c000000000456270 <__kmalloc_node+0x330> page_to_nid(): include/linux/mm.h:1294 c000000000456044: 10 00 27 e9 ld r9,16(r7) c000000000456048: 07 00 29 89 lbz r9,7(r9) <<<< r9 = NULL node_match(): mm/slub.c:2491 c00000000045604c: 00 48 99 7f cmpw cr7,r25,r9 c000000000456050: 20 02 9e 41 beq cr7,c000000000456270 <__kmalloc_node+0x330> The panic occurred in slab_alloc_node() when checking for the page's node: object = c->freelist; page = c->page; if (unlikely(!object || !node_match(page, node))) { object = __slab_alloc(s, gfpflags, node, addr, c); stat(s, ALLOC_SLOWPATH); The issue is that object is not NULL while page is NULL which is odd but may happen if the cache flush happened after loading object but before loading page. Thus checking for the page pointer is required too. The cache flush is done through an inter processor interrupt when a piece of memory is off-lined. That interrupt is triggered when a memory hot-unplug operation is initiated and offline_pages() is calling the slub's MEM_GOING_OFFLINE callback slab_mem_going_offline_callback() which is calling flush_cpu_slab(). If that interrupt is caught between the reading of c->freelist and the reading of c->page, this could lead to such a situation. That situation is expected and the later call to this_cpu_cmpxchg_double() will detect the change to c->freelist and redo the whole operation. In commit 6159d0f5c03e ("mm/slub.c: page is always non-NULL in node_match()") check on the page pointer has been removed assuming that page is always valid when it is called. It happens that this is not true in that particular case, so check for page before calling node_match() here. Link: https://lkml.kernel.org/r/20201027190406.33283-1-ldufour@linux.ibm.com Fixes: 6159d0f5c03e ("mm/slub.c: page is always non-NULL in node_match()") Signed-off-by: Laurent Dufour <ldufour(a)linux.ibm.com> Acked-by: Vlastimil Babka <vbabka(a)suse.cz> Acked-by: Christoph Lameter <cl(a)linux.com> Cc: Wei Yang <richard.weiyang(a)gmail.com> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: David Rientjes <rientjes(a)google.com> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Nathan Lynch <nathanl(a)linux.ibm.com> Cc: Scott Cheloha <cheloha(a)linux.ibm.com> Cc: Michal Hocko <mhocko(a)suse.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/slub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/slub.c~mm-slub-fix-panic-in-slab_alloc_node +++ a/mm/slub.c @@ -2852,7 +2852,7 @@ redo: object = c->freelist; page = c->page; - if (unlikely(!object || !node_match(page, node))) { + if (unlikely(!object || !page || !node_match(page, node))) { object = __slab_alloc(s, gfpflags, node, addr, c); } else { void *next_object = get_freepointer_safe(s, object); _ Patches currently in -mm which might be from ldufour(a)linux.ibm.com are

4 years, 11 months

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