lkml.org 
[lkml]   [2020]   [Mar]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH] scsi: libiscsi: we should take compound page into account also
Date

On Fri, Mar 27, 2020 at 9:36 AM <chenanqing@oppo.com> wrote:
>
> From: Chen Anqing <chenanqing@oppo.com>
> To: Ilya Dryomov <idryomov@gmail.com>
> Cc: Jeff Layton <jlayton@kernel.org>,
> Sage Weil <sage@redhat.com>,
> Jakub Kicinski <kuba@kernel.org>,
> ceph-devel@vger.kernel.org,
> netdev@vger.kernel.org,
> linux-kernel@vger.kernel.org,
> chenanqing@oppo.com
> Subject: [PATCH] libceph: we should take compound page into account
> also
> Date: Fri, 27 Mar 2020 04:36:30 -0400
> Message-Id: <20200327083630.36296-1-chenanqing@oppo.com>
> X-Mailer: git-send-email 2.18.2
>
> the patch is occur at a real crash,which slab is come from a compound
> page,so we need take the compound page into account also.
> fixed commit 7e241f647dc7 ("libceph: fall back to sendmsg for slab pages")'
>
> Signed-off-by: Chen Anqing <chenanqing@oppo.com>
> ---
> net/ceph/messenger.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index
> f8ca5edc5f2c..e08c1c334cd9 100644
> --- a/net/ceph/messenger.c
> +++ b/net/ceph/messenger.c
> @@ -582,7 +582,7 @@ static int ceph_tcp_sendpage(struct socket *sock, struct page *page,
> * coalescing neighboring slab objects into a single frag which
> * triggers one of hardened usercopy checks.
> */
> - if (page_count(page) >= 1 && !PageSlab(page))
> + if (page_count(page) >= 1 && !PageSlab(compound_head(page)))
> sendpage = sock->ops->sendpage;
> else
> sendpage = sock_no_sendpage;

>Hi Chen,

>AFAICT compound pages should already be taken into account, because PageSlab is defined as:
>
> __PAGEFLAG(Slab, slab, PF_NO_TAIL)
>
> #define __PAGEFLAG(uname, lname, policy) \
> TESTPAGEFLAG(uname, lname, policy) \
> __SETPAGEFLAG(uname, lname, policy) \
> __CLEARPAGEFLAG(uname, lname, policy)
>
> #define TESTPAGEFLAG(uname, lname, policy) \
> static __always_inline int Page##uname(struct page *page) \
> { return test_bit(PG_##lname, &policy(page, 0)->flags); }
>
> and PF_NO_TAIL policy is defined as:

> #define PF_NO_TAIL(page, enforce) ({ \
> VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
> PF_POISONED_CHECK(compound_head(page)); })

> So compound_head() is called behind the scenes.

>Could you please explain what crash did you observe in more detail?
>Perhaps you backported this patch to an older kernel?

>Thanks,

> Ilya
Hi llya,
thank you for you reply so quickly.
I have apply the patch in my server ,it's work fine ,so I thought it should be pushed to the community, but I Know nothing about the
PageSlab has been changed ,because I use the 3.10.0- all the time ,sorry for that. i also send patch to scsi group also.

my crash is writed below:

[85774.558604] usercopy: kernel memory exposure attempt detected from ffff9cba0bf75400 (kmalloc-512) (1024 bytes)
[85774.559261] ------------[ cut here ]------------
[85774.559839] kernel BUG at mm/usercopy.c:72!
[85774.560367] invalid opcode: 0000 [#1] SMP
[85774.560879] Modules linked in: cmac arc4 md4 nls_utf8 cifs ccm dns_resolver xfs iscsi_tcp libiscsi_tcp libiscsi iptable_raw iptable_mangle sch_sfq sch_htb scsi_transport_iscsi veth ipt_MASQUERADE nf_nat_masquerade_ipv4 xt_comment xt_mark iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 xt_addrtype iptable_filter xt_conntrack nf_nat nf_conntrack br_netfilter bridge stp llc dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio libcrc32c loop bonding fuse sunrpc dm_mirror dm_region_hash dm_log dm_mod dell_smbios dell_wmi_descriptor iTCO_wdt iTCO_vendor_support dcdbas skx_edac intel_powerclamp coretemp intel_rapl iosf_mbi kvm_intel kvm irqbypass crc32_pclmul ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd ipmi_ssif sg pcspkr mei_me lpc_ich i2c_i801 mei wmi ipmi_si
[85774.564343] ipmi_devintf ipmi_msghandler acpi_pad acpi_power_meter ip_tables ext4 mbcache jbd2 sd_mod crc_t10dif crct10dif_generic crct10dif_pclmul crct10dif_common crc32c_intel mgag200 drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm megaraid_sas drm ixgbe ahci igb drm_panel_orientation_quirks libahci mdio libata ptp pps_core dca i2c_algo_bit nfit libnvdimm
[85774.566809] CPU: 9 PID: 28054 Comm: tgtd Kdump: loaded Not tainted 3.10.0-957.27.2.el7.x86_64 #1
[85774.567446] Hardware name: Dell Inc. PowerEdge R740/0YNX56, BIOS 2.4.8 11/26/2019
[85774.568094] task: ffff9cb12e1e0000 ti: ffff9cb124224000 task.ti: ffff9cb124224000
[85774.568754] RIP: 0010:[<ffffffff9803f557>] [<ffffffff9803f557>] __check_object_size+0x87/0x250
[85774.569419] RSP: 0018:ffff9cb124227b98 EFLAGS: 00010246
[85774.570072] RAX: 0000000000000062 RBX: ffff9cba0bf75400 RCX: 0000000000000000
[85774.570723] RDX: 0000000000000000 RSI: ffff9cc13bf13898 RDI: ffff9cc13bf13898
[85774.571372] RBP: ffff9cb124227bb8 R08: 0000000000000000 R09: ffff9cb1313e6f00
[85774.572017] R10: 000000000003bc95 R11: 0000000000000001 R12: 0000000000000400
[85774.572669] R13: 0000000000000001 R14: ffff9cba0bf75800 R15: 0000000000000400
[85774.573325] FS: 00007f41a122a740(0000) GS:ffff9cc13bf00000(0000) knlGS:0000000000000000
[85774.573994] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[85774.574655] CR2: 0000000003236fe0 CR3: 0000001023138000 CR4: 00000000007607e0
[85774.575314] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[85774.575964] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[85774.576609] PKRU: 55555554
[85774.577242] Call Trace:
[85774.577880] [<ffffffff9818dd9d>] memcpy_toiovec+0x4d/0xb0
[85774.578531] [<ffffffff9842c858>] skb_copy_datagram_iovec+0x128/0x280
[85774.579190] [<ffffffff9849372a>] tcp_recvmsg+0x22a/0xb30
[85774.579838] [<ffffffff984c2340>] inet_recvmsg+0x80/0xb0
[85774.580474] [<ffffffff9841a6ec>] sock_aio_read.part.9+0x14c/0x170
[85774.581097] [<ffffffff9841a731>] sock_aio_read+0x21/0x30
[85774.581714] [<ffffffff98041b33>] do_sync_read+0x93/0xe0
[85774.582328] [<ffffffff98042615>] vfs_read+0x145/0x170
[85774.582934] [<ffffffff9804342f>] SyS_read+0x7f/0xf0
[85774.583543] [<ffffffff98576ddb>] system_call_fastpath+0x22/0x27
[85774.584158] Code: 45 d1 48 c7 c6 05 c3 87 98 48 c7 c1 f6 57 88 98 48 0f 45 f1 49 89 c0 4d 89 e1 48 89 d9 48 c7 c7 00 27 88 98 31 c0 e8 30 e4 51 00 <0f> 0b 0f 1f 80 00 00 00 00 48 c7 c0 00 00 e0 97 4c 39 f0 73 0d
[85774.585495] RIP [<ffffffff9803f557>] __check_object_size+0x87/0x250
[85774.586135] RSP <ffff9cb124227b98>

crash> dis -l skb_copy_datagram_iovec
/usr/src/debug/kernel-3.10.0-957.27.2.el7/linux-3.10.0-957.27.2.el7.x86_64/net/core/datagram.c: 395
0xffffffff9842c730 <skb_copy_datagram_iovec>: nopl 0x0(%rax,%rax,1) [FTRACE NOP]
0xffffffff9842c735 <skb_copy_datagram_iovec+5>: push %rbp
0xffffffff9842c736 <skb_copy_datagram_iovec+6>: mov %rsp,%rbp
0xffffffff9842c739 <skb_copy_datagram_iovec+9>: push %r15
0xffffffff9842c73b <skb_copy_datagram_iovec+11>: push %r14
0xffffffff9842c73d <skb_copy_datagram_iovec+13>: mov %rdi,%r14
0xffffffff9842c740 <skb_copy_datagram_iovec+16>: push %r13
0xffffffff9842c742 <skb_copy_datagram_iovec+18>: push %r12
0xffffffff9842c744 <skb_copy_datagram_iovec+20>: mov %esi,%r12d
0xffffffff9842c747 <skb_copy_datagram_iovec+23>: push %rbx----------------:skb is store in rbx and I get it from stack
0xffffffff9842c748 <skb_copy_datagram_iovec+24>: mov %ecx,%ebx
0xffffffff9842c74a <skb_copy_datagram_iovec+26>: sub $0x28,%rsp

crash> sk_buff.len ffff9cb0e3b388f8
len = 1024

crash> sk_buff.data_len ffff9cb0e3b388f8
data_len = 1024

crash> sk_buff.head ffff9cb0e3b388f8
head = 0xffff9cbf9c679400 ""

crash> sk_buff.end ffff9cb0e3b388f8 -x
end = 0x2c0
crash> px 0xffff9cbf9c679400 + 0x2c0
$5 = 0xffff9cbf9c6796c0

crash> skb_shared_info 0xffff9cbf9c6796c0
struct skb_shared_info {
nr_frags = 1 '\001',
tx_flags = 32 ' ',
gso_size = 0,
gso_segs = 1,
gso_type = 0,
frag_list = 0x0,
hwtstamps = {


crash> skb_shared_info.frags 0xffff9cbf9c6796c0
frags = {{
page = {
p = 0xfffff597a42fdd40-----it the page which store the data
},
page_offset = 1024,
size = 1024
}, {

crash> kmem ffff9cba0bf75400------------the address which is reported in the bugon line,
CACHE NAME OBJSIZE ALLOCATED TOTAL SLABS SSIZE
ffff9ca27fc07600 kmalloc-512 512 242454 464512 7258 32k
SLAB MEMORY NODE TOTAL ALLOCATED FREE
fffff597a42fdc00 ffff9cba0bf70000 1 64 59 5
FREE / [ALLOCATED]
[ffff9cba0bf75400]

PAGE PHYSICAL MAPPING INDEX CNT FLAGS
fffff597a42fdd40 190bf75000 0 0 0 6fffff00008000 tail

and I found the page is not the head page ,it is a tail page of compound page.

so I search the linux code ,I get the patch:
commit 7e241f647dc7 ("libceph: fall back to sendmsg for slab pages")'
commit 08b11eaccfcf ("scsi: libiscsi: fall back to sendmsg for slab pages").

sorry again for troubling you.
________________________________
OPPO

本电子邮件及其附件含有OPPO公司的保密信息,仅限于邮件指明的收件人使用(包含个人及群组)。禁止任何人在未经授权的情况下以任何形式使用。如果您错收了本邮件,请立即以电子邮件通知发件人并删除本邮件及其附件。

This e-mail and its attachments contain confidential information from OPPO, which is intended only for the person or entity whose address is listed above. Any use of the information contained herein in any way (including, but not limited to, total or partial disclosure, reproduction, or dissemination) by persons other than the intended recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender by phone or email immediately and delete it!
\
 
 \ /
  Last update: 2020-03-27 11:05    [W:0.474 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site