mm/memory-failure: fix deadlock when hugetlb_optimize_vmemmap is enabled
JIRA: https://issues.redhat.com/browse/RHEL-35090
JIRA: https://issues.redhat.com/browse/RHEL-35091
CVE: CVE-2024-26987
Tested: no reproducer, can't reproduce it myself
commit 1983184c22dd84a4d95a71e5c6775c2638557dc7
Author: Miaohe Lin linmiaohe@huawei.com
Date: Sun Apr 7 16:54:56 2024 +0800
mm/memory-failure: fix deadlock when hugetlb_optimize_vmemmap is enabled
When I did hard offline test with hugetlb pages, below deadlock occurs:
======================================================
WARNING: possible circular locking dependency detected
6.8.0-11409-gf6cef5f8c37f #1 Not tainted
------------------------------------------------------
bash/46904 is trying to acquire lock:
ffffffffabe68910 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_slow_dec+0x16/0x60
but task is already holding lock:
ffffffffabf92ea8 (pcp_batch_high_lock){+.+.}-{3:3}, at: zone_pcp_disable+0x16/0x40
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (pcp_batch_high_lock){+.+.}-{3:3}:
__mutex_lock+0x6c/0x770
page_alloc_cpu_online+0x3c/0x70
cpuhp_invoke_callback+0x397/0x5f0
__cpuhp_invoke_callback_range+0x71/0xe0
_cpu_up+0xeb/0x210
cpu_up+0x91/0xe0
cpuhp_bringup_mask+0x49/0xb0
bringup_nonboot_cpus+0xb7/0xe0
smp_init+0x25/0xa0
kernel_init_freeable+0x15f/0x3e0
kernel_init+0x15/0x1b0
ret_from_fork+0x2f/0x50
ret_from_fork_asm+0x1a/0x30
-> #0 (cpu_hotplug_lock){++++}-{0:0}:
__lock_acquire+0x1298/0x1cd0
lock_acquire+0xc0/0x2b0
cpus_read_lock+0x2a/0xc0
static_key_slow_dec+0x16/0x60
__hugetlb_vmemmap_restore_folio+0x1b9/0x200
dissolve_free_huge_page+0x211/0x260
__page_handle_poison+0x45/0xc0
memory_failure+0x65e/0xc70
hard_offline_page_store+0x55/0xa0
kernfs_fop_write_iter+0x12c/0x1d0
vfs_write+0x387/0x550
ksys_write+0x64/0xe0
do_syscall_64+0xca/0x1e0
entry_SYSCALL_64_after_hwframe+0x6d/0x75
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(pcp_batch_high_lock);
lock(cpu_hotplug_lock);
lock(pcp_batch_high_lock);
rlock(cpu_hotplug_lock);
*** DEADLOCK ***
5 locks held by bash/46904:
stack backtrace:
CPU: 10 PID: 46904 Comm: bash Kdump: loaded Not tainted 6.8.0-11409-gf6cef5f8c37f #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x68/0xa0
check_noncircular+0x129/0x140
__lock_acquire+0x1298/0x1cd0
lock_acquire+0xc0/0x2b0
cpus_read_lock+0x2a/0xc0
static_key_slow_dec+0x16/0x60
__hugetlb_vmemmap_restore_folio+0x1b9/0x200
dissolve_free_huge_page+0x211/0x260
__page_handle_poison+0x45/0xc0
memory_failure+0x65e/0xc70
hard_offline_page_store+0x55/0xa0
kernfs_fop_write_iter+0x12c/0x1d0
vfs_write+0x387/0x550
ksys_write+0x64/0xe0
do_syscall_64+0xca/0x1e0
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7fc862314887
Code: 10 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
RSP: 002b:00007fff19311268 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007fc862314887
RDX: 000000000000000c RSI: 000056405645fe10 RDI: 0000000000000001
RBP: 000056405645fe10 R08: 00007fc8623d1460 R09: 000000007fffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000c
R13: 00007fc86241b780 R14: 00007fc862417600 R15: 00007fc862416a00
In short, below scene breaks the lock dependency chain:
memory_failure
__page_handle_poison
zone_pcp_disable -- lock(pcp_batch_high_lock)
dissolve_free_huge_page
__hugetlb_vmemmap_restore_folio
static_key_slow_dec
cpus_read_lock -- rlock(cpu_hotplug_lock)
Fix this by calling drain_all_pages() instead.
This issue won't occur until commit a6b40850c442 ("mm: hugetlb: replace
hugetlb_free_vmemmap_enabled with a static_key"). As it introduced
rlock(cpu_hotplug_lock) in dissolve_free_huge_page() code path while
lock(pcp_batch_high_lock) is already in the __page_handle_poison().
[linmiaohe@huawei.com: extend comment per Oscar]
[akpm@linux-foundation.org: reflow block comment]
Link: https://lkml.kernel.org/r/20240407085456.2798193-1-linmiaohe@huawei.com
Fixes: a6b40850c442 ("mm: hugetlb: replace hugetlb_free_vmemmap_enabled with a static_key")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Aristeu Rozanski arozansk@redhat.com
Edited by Aristeu Rozanski