From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
"Ilya Lipnitskiy" <ilya.lipnitskiy@gmail.com>,
"Hugh Dickins" <hughd@google.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"周琰杰 " <zhouyanjie@wanyeetech.com>,
"Linus Torvalds" <torvalds@linux-foundation.org>
Subject: [PATCH 4.19 35/56] mm: fix race by making init_zero_pfn() early_initcall
Date: Mon, 5 Apr 2021 10:54:06 +0200 [thread overview]
Message-ID: <20210405085023.658580585@linuxfoundation.org> (raw)
In-Reply-To: <20210405085022.562176619@linuxfoundation.org>
From: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
commit e720e7d0e983bf05de80b231bccc39f1487f0f16 upstream.
There are code paths that rely on zero_pfn to be fully initialized
before core_initcall. For example, wq_sysfs_init() is a core_initcall
function that eventually results in a call to kernel_execve, which
causes a page fault with a subsequent mmput. If zero_pfn is not
initialized by then it may not get cleaned up properly and result in an
error:
BUG: Bad rss-counter state mm:(ptrval) type:MM_ANONPAGES val:1
Here is an analysis of the race as seen on a MIPS device. On this
particular MT7621 device (Ubiquiti ER-X), zero_pfn is PFN 0 until
initialized, at which point it becomes PFN 5120:
1. wq_sysfs_init calls into kobject_uevent_env at core_initcall:
kobject_uevent_env+0x7e4/0x7ec
kset_register+0x68/0x88
bus_register+0xdc/0x34c
subsys_virtual_register+0x34/0x78
wq_sysfs_init+0x1c/0x4c
do_one_initcall+0x50/0x1a8
kernel_init_freeable+0x230/0x2c8
kernel_init+0x10/0x100
ret_from_kernel_thread+0x14/0x1c
2. kobject_uevent_env() calls call_usermodehelper_exec() which executes
kernel_execve asynchronously.
3. Memory allocations in kernel_execve cause a page fault, bumping the
MM reference counter:
add_mm_counter_fast+0xb4/0xc0
handle_mm_fault+0x6e4/0xea0
__get_user_pages.part.78+0x190/0x37c
__get_user_pages_remote+0x128/0x360
get_arg_page+0x34/0xa0
copy_string_kernel+0x194/0x2a4
kernel_execve+0x11c/0x298
call_usermodehelper_exec_async+0x114/0x194
4. In case zero_pfn has not been initialized yet, zap_pte_range does
not decrement the MM_ANONPAGES RSS counter and the BUG message is
triggered shortly afterwards when __mmdrop checks the ref counters:
__mmdrop+0x98/0x1d0
free_bprm+0x44/0x118
kernel_execve+0x160/0x1d8
call_usermodehelper_exec_async+0x114/0x194
ret_from_kernel_thread+0x14/0x1c
To avoid races such as described above, initialize init_zero_pfn at
early_initcall level. Depending on the architecture, ZERO_PAGE is
either constant or gets initialized even earlier, at paging_init, so
there is no issue with initializing zero_pfn earlier.
Link: https://lkml.kernel.org/r/CALCv0x2YqOXEAy2Q=hafjhHCtTHVodChv1qpM=niAXOpqEbt7w@mail.gmail.com
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: stable@vger.kernel.org
Tested-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
mm/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -148,7 +148,7 @@ static int __init init_zero_pfn(void)
zero_pfn = page_to_pfn(ZERO_PAGE(0));
return 0;
}
-core_initcall(init_zero_pfn);
+early_initcall(init_zero_pfn);
#if defined(SPLIT_RSS_COUNTING)
next prev parent reply other threads:[~2021-04-05 9:02 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-05 8:53 [PATCH 4.19 00/56] 4.19.185-rc1 review Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 01/56] selinux: vsock: Set SID for socket returned by accept() Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 02/56] tcp: relookup sock for RST+ACK packets handled by obsolete req sock Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 03/56] ipv6: weaken the v4mapped source check Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 04/56] ext4: fix bh ref count on error paths Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 05/56] rpc: fix NULL dereference on kmalloc failure Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 06/56] ASoC: rt5640: Fix dac- and adc- vol-tlv values being off by a factor of 10 Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 07/56] ASoC: rt5651: " Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 08/56] ASoC: sgtl5000: set DAP_AVC_CTRL register to correct default value on probe Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 09/56] ASoC: es8316: Simplify adc_pga_gain_tlv table Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 10/56] ASoC: cs42l42: Fix Bitclock polarity inversion Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 11/56] ASoC: cs42l42: Fix channel width support Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 12/56] ASoC: cs42l42: Fix mixer volume control Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 13/56] ASoC: cs42l42: Always wait at least 3ms after reset Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 14/56] vhost: Fix vhost_vq_reset() Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 15/56] scsi: st: Fix a use after free in st_open() Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 16/56] scsi: qla2xxx: Fix broken #endif placement Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 17/56] staging: comedi: cb_pcidas: fix request_irq() warn Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 18/56] staging: comedi: cb_pcidas64: " Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 19/56] ASoC: rt5659: Update MCLK rate in set_sysclk() Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 20/56] thermal/core: Add NULL pointer check before using cooling device stats Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 21/56] locking/ww_mutex: Simplify use_ww_ctx & ww_ctx handling Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 22/56] ext4: do not iput inode under running transaction in ext4_rename() Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 23/56] brcmfmac: clear EAP/association status bits on linkdown events Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 24/56] ath10k: hold RCU lock when calling ieee80211_find_sta_by_ifaddr() Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 25/56] net: ethernet: aquantia: Handle error cleanup of start on open Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 26/56] appletalk: Fix skb allocation size in loopback case Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 27/56] net: wan/lmc: unregister device when no matching device is found Greg Kroah-Hartman
2021-04-05 8:53 ` [PATCH 4.19 28/56] bpf: Remove MTU check in __bpf_skb_max_len Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 29/56] ALSA: usb-audio: Apply sample rate quirk to Logitech Connect Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 30/56] ALSA: hda/realtek: fix a determine_headset_type issue for a Dell AIO Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 31/56] ALSA: hda/realtek: call alc_update_headset_mode() in hp_automute_hook Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 32/56] PM: runtime: Fix race getting/putting suppliers at probe Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 33/56] PM: runtime: Fix ordering in pm_runtime_get_suppliers() Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 34/56] tracing: Fix stack trace event size Greg Kroah-Hartman
2021-04-05 8:54 ` Greg Kroah-Hartman [this message]
2021-04-05 8:54 ` [PATCH 4.19 36/56] drm/amdgpu: fix offset calculation in amdgpu_vm_bo_clear_mappings() Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 37/56] drm/amdgpu: check alignment on CPU page for bo map Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 38/56] reiserfs: update reiserfs_xattrs_initialized() condition Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 39/56] pinctrl: rockchip: fix restore error in resume Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 40/56] extcon: Add stubs for extcon_register_notifier_all() functions Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 41/56] extcon: Fix error handling in extcon_dev_register Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 42/56] firewire: nosy: Fix a use-after-free bug in nosy_ioctl() Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 43/56] usbip: vhci_hcd fix shift out-of-bounds in vhci_hub_control() Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 44/56] USB: quirks: ignore remote wake-up on Fibocom L850-GL LTE modem Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 45/56] usb: musb: Fix suspend with devices connected for a64 Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 46/56] usb: xhci-mtk: fix broken streams issue on 0.96 xHCI Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 47/56] cdc-acm: fix BREAK rx code path adding necessary calls Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 48/56] USB: cdc-acm: untangle a circular dependency between callback and softint Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 49/56] USB: cdc-acm: downgrade message to debug Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 50/56] USB: cdc-acm: fix double free on probe failure Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 51/56] USB: cdc-acm: fix use-after-free after " Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 52/56] usb: gadget: udc: amd5536udc_pci fix null-ptr-dereference Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 53/56] usb: dwc2: Fix HPRT0.PrtSusp bit setting for HiKey 960 board Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 54/56] staging: rtl8192e: Fix incorrect source in memcpy() Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 55/56] staging: rtl8192e: Change state information from u16 to u8 Greg Kroah-Hartman
2021-04-05 8:54 ` [PATCH 4.19 56/56] drivers: video: fbcon: fix NULL dereference in fbcon_cursor() Greg Kroah-Hartman
2021-04-05 17:57 ` [PATCH 4.19 00/56] 4.19.185-rc1 review Guenter Roeck
2021-04-06 0:28 ` Shuah Khan
2021-04-06 4:02 ` Naresh Kamboju
2021-04-07 2:05 ` Samuel Zou
2021-04-07 8:23 ` Pavel Machek
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