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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, apopple@nvidia.com,
	bsingharora@gmail.com, dan.j.williams@intel.com,
	daniel.vetter@ffwll.ch, david@redhat.com,
	gregkh@linuxfoundation.org, jglisse@redhat.com,
	jhubbard@nvidia.com, linux-mm@kvack.org,
	mm-commits@vger.kernel.org, smuchun@gmail.com,
	torvalds@linux-foundation.org
Subject: [patch 66/91] kernel/resource: fix locking in request_free_mem_region
Date: Thu, 06 May 2021 18:05:30 -0700	[thread overview]
Message-ID: <20210507010530.uEl5utzt5%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210506180126.03e1baee7ca52bedb6cc6003@linux-foundation.org>

From: Alistair Popple <apopple@nvidia.com>
Subject: kernel/resource: fix locking in request_free_mem_region

request_free_mem_region() is used to find an empty range of physical
addresses for hotplugging ZONE_DEVICE memory.  It does this by iterating
over the range of possible addresses using region_intersects() to see if
the range is free before calling request_mem_region() to allocate the
region.

However the resource_lock is dropped between these two calls meaning by
the time request_mem_region() is called in request_free_mem_region()
another thread may have already reserved the requested region.  This
results in unexpected failures and a message in the kernel log from
hitting this condition:

        /*
         * mm/hmm.c reserves physical addresses which then
         * become unavailable to other users.  Conflicts are
         * not expected.  Warn to aid debugging if encountered.
         */
        if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
                pr_warn("Unaddressable device %s %pR conflicts with %pR",
                        conflict->name, conflict, res);

These unexpected failures can be corrected by holding resource_lock across
the two calls.  This also requires memory allocation to be performed prior
to taking the lock.

Link: https://lkml.kernel.org/r/20210419070109.4780-3-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Muchun Song <smuchun@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/resource.c |   45 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 38 insertions(+), 7 deletions(-)

--- a/kernel/resource.c~kernel-resource-fix-locking-in-request_free_mem_region
+++ a/kernel/resource.c
@@ -1780,25 +1780,56 @@ static struct resource *__request_free_m
 {
 	resource_size_t end, addr;
 	struct resource *res;
+	struct region_devres *dr = NULL;
 
 	size = ALIGN(size, 1UL << PA_SECTION_SHIFT);
 	end = min_t(unsigned long, base->end, (1UL << MAX_PHYSMEM_BITS) - 1);
 	addr = end - size + 1UL;
 
+	res = alloc_resource(GFP_KERNEL);
+	if (!res)
+		return ERR_PTR(-ENOMEM);
+
+	if (dev) {
+		dr = devres_alloc(devm_region_release,
+				sizeof(struct region_devres), GFP_KERNEL);
+		if (!dr) {
+			free_resource(res);
+			return ERR_PTR(-ENOMEM);
+		}
+	}
+
+	write_lock(&resource_lock);
 	for (; addr > size && addr >= base->start; addr -= size) {
-		if (region_intersects(addr, size, 0, IORES_DESC_NONE) !=
+		if (__region_intersects(addr, size, 0, IORES_DESC_NONE) !=
 				REGION_DISJOINT)
 			continue;
 
-		if (dev)
-			res = devm_request_mem_region(dev, addr, size, name);
-		else
-			res = request_mem_region(addr, size, name);
-		if (!res)
-			return ERR_PTR(-ENOMEM);
+		if (!__request_region_locked(res, &iomem_resource, addr, size,
+						name, 0))
+			break;
+
+		if (dev) {
+			dr->parent = &iomem_resource;
+			dr->start = addr;
+			dr->n = size;
+			devres_add(dev, dr);
+		}
+
 		res->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY;
+		write_unlock(&resource_lock);
+
+		/*
+		 * A driver is claiming this region so revoke any mappings.
+		 */
+		revoke_iomem(res);
 		return res;
 	}
+	write_unlock(&resource_lock);
+
+	free_resource(res);
+	if (dr)
+		devres_free(dr);
 
 	return ERR_PTR(-ERANGE);
 }
_

  parent reply	other threads:[~2021-05-07  1:05 UTC|newest]

Thread overview: 119+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-07  1:01 incoming Andrew Morton
2021-05-07  1:02 ` [patch 01/91] alpha: eliminate old-style function definitions Andrew Morton
2021-05-07  1:02 ` [patch 02/91] alpha: csum_partial_copy.c: add function prototypes from <net/checksum.h> Andrew Morton
2021-05-07  1:02 ` [patch 03/91] fs/proc/generic.c: fix incorrect pde_is_permanent check Andrew Morton
2021-05-07  1:02 ` [patch 04/91] proc: save LOC in __xlate_proc_name() Andrew Morton
2021-05-07  2:24   ` Linus Torvalds
2021-05-07  1:02 ` [patch 05/91] proc: mandate ->proc_lseek in "struct proc_ops" Andrew Morton
2021-05-07  1:02 ` [patch 06/91] proc: delete redundant subset=pid check Andrew Morton
2021-05-07  1:02 ` [patch 07/91] selftests: proc: test subset=pid Andrew Morton
2021-05-07  1:02 ` [patch 08/91] proc/sysctl: fix function name error in comments Andrew Morton
2021-05-07  1:02 ` [patch 09/91] include: remove pagemap.h from blkdev.h Andrew Morton
2021-05-07  1:02 ` [patch 10/91] kernel.h: drop inclusion in bitmap.h Andrew Morton
2021-05-07  1:02 ` [patch 11/91] linux/profile.h: remove unnecessary declaration Andrew Morton
2021-05-07  1:02 ` [patch 12/91] kernel/async.c: fix pr_debug statement Andrew Morton
2021-05-07  1:02 ` [patch 13/91] kernel/cred.c: make init_groups static Andrew Morton
2021-05-07  1:02 ` [patch 14/91] tools: disable -Wno-type-limits Andrew Morton
2021-05-07  1:02 ` [patch 15/91] tools: bitmap: sync function declarations with the kernel Andrew Morton
2021-05-07  1:02 ` [patch 16/91] tools: sync BITMAP_LAST_WORD_MASK() macro " Andrew Morton
2021-05-07  1:02 ` [patch 17/91] arch: rearrange headers inclusion order in asm/bitops for m68k, sh and h8300 Andrew Morton
2021-05-07  1:02 ` [patch 18/91] lib: extend the scope of small_const_nbits() macro Andrew Morton
2021-05-07  1:03 ` [patch 19/91] tools: sync small_const_nbits() macro with the kernel Andrew Morton
2021-05-07  1:03 ` [patch 20/91] lib: inline _find_next_bit() wrappers Andrew Morton
2021-05-07  1:03 ` [patch 21/91] tools: sync find_next_bit implementation Andrew Morton
2021-05-07  1:03 ` [patch 22/91] lib: add fast path for find_next_*_bit() Andrew Morton
2021-05-07  1:03 ` [patch 23/91] lib: add fast path for find_first_*_bit() and find_last_bit() Andrew Morton
2021-05-07  1:03 ` [patch 24/91] tools: sync lib/find_bit implementation Andrew Morton
2021-05-07  1:03 ` [patch 25/91] MAINTAINERS: add entry for the bitmap API Andrew Morton
2021-05-07  1:03 ` [patch 26/91] lib/bch.c: fix a typo in the file bch.c Andrew Morton
2021-05-07  1:03 ` [patch 27/91] lib: fix inconsistent indenting in process_bit1() Andrew Morton
2021-05-07  1:03 ` [patch 28/91] lib/list_sort.c: fix typo in function description Andrew Morton
2021-05-07  1:03 ` [patch 29/91] lib/genalloc.c: fix a typo Andrew Morton
2021-05-07  1:03 ` [patch 30/91] lib: crc8: pointer to data block should be const Andrew Morton
2021-05-07  1:03 ` [patch 31/91] lib: stackdepot: turn depot_lock spinlock to raw_spinlock Andrew Morton
2021-05-07  1:03 ` [patch 32/91] lib/percpu_counter: tame kernel-doc compile warning Andrew Morton
2021-05-07  1:03 ` [patch 33/91] lib/genalloc: add parameter description to fix doc " Andrew Morton
2021-05-07  1:03 ` [patch 34/91] lib: parser: clean up kernel-doc Andrew Morton
2021-05-07  1:03 ` [patch 35/91] include/linux/compat.h: remove unneeded declaration from COMPAT_SYSCALL_DEFINEx() Andrew Morton
2021-05-07  1:03 ` [patch 36/91] checkpatch: warn when missing newline in return sysfs_emit() formats Andrew Morton
2021-05-07  1:03 ` [patch 37/91] checkpatch: exclude four preprocessor sub-expressions from MACRO_ARG_REUSE Andrew Morton
2021-05-07  1:04 ` [patch 38/91] checkpatch: improve ALLOC_ARRAY_ARGS test Andrew Morton
2021-05-07  1:04 ` [patch 39/91] kselftest: introduce new epoll test case Andrew Morton
2021-05-07  1:04 ` [patch 40/91] fs/epoll: restore waking from ep_done_scan() Andrew Morton
2021-05-07  1:04 ` [patch 41/91] isofs: fix fall-through warnings for Clang Andrew Morton
2021-05-07  1:04 ` [patch 42/91] fs/nilfs2: fix misspellings using codespell tool Andrew Morton
2021-05-07  1:04 ` [patch 43/91] nilfs2: fix typos in comments Andrew Morton
2021-05-07  1:04 ` [patch 44/91] hpfs: replace one-element array with flexible-array member Andrew Morton
2021-05-07  1:04 ` [patch 45/91] do_wait: make PIDTYPE_PID case O(1) instead of O(n) Andrew Morton
2021-05-07  1:04 ` [patch 46/91] kernel/fork.c: simplify copy_mm() Andrew Morton
2021-05-07  1:04 ` [patch 47/91] kernel/fork.c: fix typos Andrew Morton
2021-05-07  1:04 ` [patch 48/91] kernel/crash_core: add crashkernel=auto for vmcore creation Andrew Morton
2021-05-07  7:25   ` Linus Torvalds
2021-05-08  3:13     ` Baoquan He
2021-05-08  3:29       ` Baoquan He
2021-05-07  8:16   ` David Hildenbrand
2021-05-08  8:51     ` Baoquan He
2021-05-08  9:22       ` David Hildenbrand
2021-05-10  4:53         ` Baoquan He
2021-05-10  8:32           ` David Hildenbrand
2021-05-10 10:43             ` Baoquan He
2021-05-10 11:01               ` David Hildenbrand
2021-05-10 11:44                 ` Dave Young
2021-05-10 11:56                   ` David Hildenbrand
2021-05-11 13:36                     ` Baoquan He
2021-05-11 16:31                       ` Mike Rapoport
2021-05-11 17:07                         ` David Hildenbrand
2021-05-12 14:51                           ` Baoquan He
2021-05-12 15:07                             ` David Hildenbrand
2021-05-13  5:04                               ` Baoquan He
2021-05-12 19:03                             ` Kairui Song
2021-05-17  8:22                             ` David Hildenbrand
2021-05-18  8:49                               ` Baoquan He
2021-05-18  8:51                                 ` David Hildenbrand
2021-05-18  9:24                                   ` Dave Young
2021-05-12 14:13                         ` Baoquan He
2021-05-12  7:42                     ` Dave Young
2021-05-07  1:04 ` [patch 49/91] kexec: add kexec reboot string Andrew Morton
2021-05-07  1:04 ` [patch 50/91] kernel: kexec_file: fix error return code of kexec_calculate_store_digests() Andrew Morton
2021-05-07  1:04 ` [patch 51/91] kexec: dump kmessage before machine_kexec Andrew Morton
2021-05-07  1:04 ` [patch 52/91] gcov: combine common code Andrew Morton
2021-05-07  1:04 ` [patch 53/91] gcov: simplify buffer allocation Andrew Morton
2021-05-07  1:04 ` [patch 54/91] gcov: use kvmalloc() Andrew Morton
2021-05-07  1:04 ` [patch 55/91] gcov: clang: drop support for clang-10 and older Andrew Morton
2021-05-07  1:04 ` [patch 56/91] smp: kernel/panic.c - silence warnings Andrew Morton
2021-05-07  1:05 ` [patch 57/91] delayacct: clear right task's flag after blkio completes Andrew Morton
2021-05-07  1:05 ` [patch 58/91] gdb: lx-symbols: store the abspath() Andrew Morton
2021-05-07  1:05 ` [patch 59/91] scripts/gdb: document lx_current is only supported by x86 Andrew Morton
2021-05-07  1:05 ` [patch 60/91] scripts/gdb: add lx_current support for arm64 Andrew Morton
2021-05-07  1:05 ` [patch 61/91] kernel/resource: make walk_system_ram_res() find all busy IORESOURCE_SYSTEM_RAM resources Andrew Morton
2021-05-07  1:05 ` [patch 62/91] kernel/resource: make walk_mem_res() find all busy IORESOURCE_MEM resources Andrew Morton
2021-05-07  1:05 ` [patch 63/91] kernel/resource: remove first_lvl / siblings_only logic Andrew Morton
2021-05-07  1:05 ` [patch 64/91] kernel/resource: allow region_intersects users to hold resource_lock Andrew Morton
2021-05-07  1:05 ` [patch 65/91] kernel/resource: refactor __request_region to allow external locking Andrew Morton
2021-05-07  1:05 ` Andrew Morton [this message]
2021-05-07  1:05 ` [patch 67/91] selftests: remove duplicate include Andrew Morton
2021-05-07  1:05 ` [patch 68/91] kernel/async.c: stop guarding pr_debug() statements Andrew Morton
2021-05-07  1:05 ` [patch 69/91] kernel/async.c: remove async_unregister_domain() Andrew Morton
2021-05-07  1:05 ` [patch 70/91] init/initramfs.c: do unpacking asynchronously Andrew Morton
2021-05-07  1:05 ` [patch 71/91] modules: add CONFIG_MODPROBE_PATH Andrew Morton
2021-05-07  1:05 ` [patch 72/91] ipc/sem.c: mundane typo fixes Andrew Morton
2021-05-07  1:05 ` [patch 73/91] mm: fix some typos and code style problems Andrew Morton
2021-05-07  1:05 ` [patch 74/91] drivers/char: remove /dev/kmem for good Andrew Morton
2021-05-07  1:06 ` [patch 75/91] mm: remove xlate_dev_kmem_ptr() Andrew Morton
2021-05-07  1:06 ` [patch 76/91] mm/vmalloc: remove vwrite() Andrew Morton
2021-05-07  1:06 ` [patch 77/91] arm: print alloc free paths for address in registers Andrew Morton
2021-05-07  1:06 ` [patch 78/91] scripts/spelling.txt: add "overlfow" Andrew Morton
2021-05-07  1:06 ` [patch 79/91] scripts/spelling.txt: add "diabled" typo Andrew Morton
2021-05-07  1:06 ` [patch 80/91] scripts/spelling.txt: add "overflw" Andrew Morton
2021-05-07  1:06 ` [patch 81/91] mm/slab.c: fix spelling mistake "disired" -> "desired" Andrew Morton
2021-05-07  1:06 ` [patch 82/91] include/linux/pgtable.h: few spelling fixes Andrew Morton
2021-05-07  1:06 ` [patch 83/91] kernel/umh.c: fix some spelling mistakes Andrew Morton
2021-05-07  1:06 ` [patch 84/91] kernel/user_namespace.c: fix typos Andrew Morton
2021-05-07  1:06 ` [patch 85/91] kernel/up.c: fix typo Andrew Morton
2021-05-07  1:06 ` [patch 86/91] kernel/sys.c: " Andrew Morton
2021-05-07  1:06 ` [patch 87/91] fs: fat: fix spelling typo of values Andrew Morton
2021-05-07  1:06 ` [patch 88/91] ipc/sem.c: spelling fix Andrew Morton
2021-05-07  1:06 ` [patch 89/91] treewide: remove editor modelines and cruft Andrew Morton
2021-05-07  1:06 ` [patch 90/91] mm: fix typos in comments Andrew Morton
2021-05-07  1:06 ` [patch 91/91] " Andrew Morton
2021-05-07  7:12 ` incoming Linus Torvalds

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