lwn.git/mm, branch v5.19-rc6

Merge tag 'mm-hotfixes-stable-2022-06-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-06-26T21:00:55+00:00

Pull hotfixes from Andrew Morton: "Minor things, mainly - mailmap updates, MAINTAINERS updates, etc. Fixes for this merge window: - fix for a damon boot hang, from SeongJae - fix for a kfence warning splat, from Jason Donenfeld - fix for zero-pfn pinning, from Alex Williamson - fix for fallocate hole punch clearing, from Mike Kravetz Fixes for previous releases: - fix for a performance regression, from Marcelo - fix for a hwpoisining BUG from zhenwei pi" * tag 'mm-hotfixes-stable-2022-06-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mailmap: add entry for Christian Marangi mm/memory-failure: disable unpoison once hw error happens hugetlbfs: zero partial pages during fallocate hole punch mm: memcontrol: reference to tools/cgroup/memcg_slabinfo.py mm: re-allow pinning of zero pfns mm/kfence: select random number before taking raw lock MAINTAINERS: add maillist information for LoongArch MAINTAINERS: update MM tree references MAINTAINERS: update Abel Vesa's email MAINTAINERS: add MEMORY HOT(UN)PLUG section and add David as reviewer MAINTAINERS: add Miaohe Lin as a memory-failure reviewer mailmap: add alias for jarkko@profian.com mm/damon/reclaim: schedule 'damon_reclaim_timer' only after 'system_wq' is initialized kthread: make it clear that kthread_create_on_node() might be terminated by any fatal signal mm: lru_cache_disable: use synchronize_rcu_expedited mm/page_isolation.c: fix one kernel-doc comment

filemap: Fix serialization adding transparent huge pages to page cache

2022-06-23T16:22:00+00:00

Commit 793917d997df ("mm/readahead: Add large folio readahead") introduced support for using large folios for filebacked pages if the filesystem supports it. page_cache_ra_order() was introduced to allocate and add these large folios to the page cache. However adding pages to the page cache should be serialized against truncation and hole punching by taking invalidate_lock. Not doing so can lead to data races resulting in stale data getting added to the page cache and marked up-to-date. See commit 730633f0b7f9 ("mm: Protect operations adding pages to page cache with invalidate_lock") for more details. This issue was found by inspection but a testcase revealed it was possible to observe in practice on XFS. Fix this by taking invalidate_lock in page_cache_ra_order(), to mirror what is done for the non-thp case in page_cache_ra_unbounded(). Signed-off-by: Alistair Popple Fixes: 793917d997df ("mm/readahead: Add large folio readahead") Reviewed-by: Jan Kara Signed-off-by: Matthew Wilcox (Oracle)

mm: Clear page->private when splitting or migrating a page

2022-06-23T16:21:44+00:00

In our efforts to remove uses of PG_private, we have found folios with the private flag clear and folio->private not-NULL. That is the root cause behind 642d51fb0775 ("ceph: check folio PG_private bit instead of folio->private"). It can also affect a few other filesystems that haven't yet reported a problem. compaction_alloc() can return a page with uninitialised page->private, and rather than checking all the callers of migrate_pages(), just zero page->private after calling get_new_page(). Similarly, the tail pages from split_huge_page() may also have an uninitialised page->private. Reported-by: Xiubo Li Tested-by: Xiubo Li Signed-off-by: Matthew Wilcox (Oracle)

filemap: Handle sibling entries in filemap_get_read_batch()

2022-06-20T20:37:45+00:00

If a read races with an invalidation followed by another read, it is possible for a folio to be replaced with a higher-order folio. If that happens, we'll see a sibling entry for the new folio in the next iteration of the loop. This manifests as a NULL pointer dereference while holding the RCU read lock. Handle this by simply returning. The next call will find the new folio and handle it correctly. The other ways of handling this rare race are more complex and it's just not worth it. Reported-by: Dave Chinner Reported-by: Brian Foster Debugged-by: Brian Foster Tested-by: Brian Foster Reviewed-by: Brian Foster Fixes: cbd59c48ae2b ("mm/filemap: use head pages in generic_file_buffered_read") Cc: stable@vger.kernel.org Signed-off-by: Matthew Wilcox (Oracle)

filemap: Correct the conditions for marking a folio as accessed

2022-06-20T20:37:45+00:00

We had an off-by-one error which meant that we never marked the first page in a read as accessed. This was visible as a slowdown when re-reading a file as pages were being evicted from cache too soon. In reviewing this code, we noticed a second bug where a multi-page folio would be marked as accessed multiple times when doing reads that were less than the size of the folio. Abstract the comparison of whether two file positions are in the same folio into a new function, fixing both of these bugs. Reported-by: Yu Kuai Reviewed-by: Kent Overstreet Signed-off-by: Matthew Wilcox (Oracle)

Merge tag 'slab-for-5.19-fixup' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

2022-06-20T14:28:51+00:00

Pull slab fixes from Vlastimil Babka: - A slub fix for PREEMPT_RT locking semantics from Sebastian. - A slub fix for state corruption due to a possible race scenario from Jann. * tag 'slab-for-5.19-fixup' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: mm/slub: add missing TID updates on slab deactivation mm/slub: Move the stackdepot related allocation out of IRQ-off section.

Merge tag 'fs_for_v5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

2022-06-17T17:09:24+00:00

Pull writeback and ext2 fixes from Jan Kara: "A fix for writeback bug which prevented machines with kdevtmpfs from booting and also one small ext2 bugfix in IO error handling" * tag 'fs_for_v5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: init: Initialize noop_backing_dev_info early ext2: fix fs corruption when trying to remove a non-empty directory with IO error

mm/memory-failure: disable unpoison once hw error happens

2022-06-17T02:11:32+00:00

Currently unpoison_memory(unsigned long pfn) is designed for soft poison(hwpoison-inject) only. Since 17fae1294ad9d, the KPTE gets cleared on a x86 platform once hardware memory corrupts. Unpoisoning a hardware corrupted page puts page back buddy only, the kernel has a chance to access the page with *NOT PRESENT* KPTE. This leads BUG during accessing on the corrupted KPTE. Suggested by David&Naoya, disable unpoison mechanism when a real HW error happens to avoid BUG like this: Unpoison: Software-unpoisoned page 0x61234 BUG: unable to handle page fault for address: ffff888061234000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 2c01067 P4D 2c01067 PUD 107267063 PMD 10382b063 PTE 800fffff9edcb062 Oops: 0002 [#1] PREEMPT SMP NOPTI CPU: 4 PID: 26551 Comm: stress Kdump: loaded Tainted: G M OE 5.18.0.bm.1-amd64 #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ... RIP: 0010:clear_page_erms+0x7/0x10 Code: ... RSP: 0000:ffffc90001107bc8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000901 RCX: 0000000000001000 RDX: ffffea0001848d00 RSI: ffffea0001848d40 RDI: ffff888061234000 RBP: ffffea0001848d00 R08: 0000000000000901 R09: 0000000000001276 R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000140dca R15: 0000000000000001 FS: 00007fd8b2333740(0000) GS:ffff88813fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888061234000 CR3: 00000001023d2005 CR4: 0000000000770ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: prep_new_page+0x151/0x170 get_page_from_freelist+0xca0/0xe20 ? sysvec_apic_timer_interrupt+0xab/0xc0 ? asm_sysvec_apic_timer_interrupt+0x1b/0x20 __alloc_pages+0x17e/0x340 __folio_alloc+0x17/0x40 vma_alloc_folio+0x84/0x280 __handle_mm_fault+0x8d4/0xeb0 handle_mm_fault+0xd5/0x2a0 do_user_addr_fault+0x1d0/0x680 ? kvm_read_and_reset_apf_flags+0x3b/0x50 exc_page_fault+0x78/0x170 asm_exc_page_fault+0x27/0x30 Link: https://lkml.kernel.org/r/20220615093209.259374-2-pizhenwei@bytedance.com Fixes: 847ce401df392 ("HWPOISON: Add unpoisoning support") Fixes: 17fae1294ad9d ("x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned") Signed-off-by: zhenwei pi Acked-by: David Hildenbrand Acked-by: Naoya Horiguchi Reviewed-by: Miaohe Lin Reviewed-by: Oscar Salvador Cc: Greg Kroah-Hartman Cc: [5.8+] Signed-off-by: Andrew Morton

mm: memcontrol: reference to tools/cgroup/memcg_slabinfo.py

2022-06-17T02:11:32+00:00

There is no slabinfo.py in tools/cgroup, but has memcg_slabinfo.py instead. Link: https://lkml.kernel.org/r/20220610024451.744135-1-yang.yang29@zte.com.cn Signed-off-by: Yang Yang Reviewed-by: Muchun Song Acked-by: Roman Gushchin Signed-off-by: Andrew Morton

mm/kfence: select random number before taking raw lock

2022-06-17T02:11:31+00:00

The RNG uses vanilla spinlocks, not raw spinlocks, so kfence should pick its random numbers before taking its raw spinlocks. This also has the nice effect of doing less work inside the lock. It should fix a splat that Geert saw with CONFIG_PROVE_RAW_LOCK_NESTING: dump_backtrace.part.0+0x98/0xc0 show_stack+0x14/0x28 dump_stack_lvl+0xac/0xec dump_stack+0x14/0x2c __lock_acquire+0x388/0x10a0 lock_acquire+0x190/0x2c0 _raw_spin_lock_irqsave+0x6c/0x94 crng_make_state+0x148/0x1e4 _get_random_bytes.part.0+0x4c/0xe8 get_random_u32+0x4c/0x140 __kfence_alloc+0x460/0x5c4 kmem_cache_alloc_trace+0x194/0x1dc __kthread_create_on_node+0x5c/0x1a8 kthread_create_on_node+0x58/0x7c printk_start_kthread.part.0+0x34/0xa8 printk_activate_kthreads+0x4c/0x54 do_one_initcall+0xec/0x278 kernel_init_freeable+0x11c/0x214 kernel_init+0x24/0x124 ret_from_fork+0x10/0x20 Link: https://lkml.kernel.org/r/20220609123319.17576-1-Jason@zx2c4.com Fixes: d4150779e60f ("random32: use real rng for non-deterministic randomness") Signed-off-by: Jason A. Donenfeld Reported-by: Geert Uytterhoeven Tested-by: Geert Uytterhoeven Reviewed-by: Marco Elver Reviewed-by: Petr Mladek Cc: John Ogness Cc: Alexander Potapenko Cc: Dmitry Vyukov Signed-off-by: Andrew Morton