linux.git/net/smc, branch v6.4

net/smc: Avoid to access invalid RMBs' MRs in SMCRv1 ADD LINK CONT

2023-06-03T19:51:04+00:00

SMCRv1 has a similar issue to SMCRv2 (see link below) that may access
invalid MRs of RMBs when construct LLC ADD LINK CONT messages.

 BUG: kernel NULL pointer dereference, address: 0000000000000014
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 5 PID: 48 Comm: kworker/5:0 Kdump: loaded Tainted: G W   E      6.4.0-rc3+ #49
 Workqueue: events smc_llc_add_link_work [smc]
 RIP: 0010:smc_llc_add_link_cont+0x160/0x270 [smc]
 RSP: 0018:ffffa737801d3d50 EFLAGS: 00010286
 RAX: ffff964f82144000 RBX: ffffa737801d3dd8 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff964f81370c30
 RBP: ffffa737801d3dd4 R08: ffff964f81370000 R09: ffffa737801d3db0
 R10: 0000000000000001 R11: 0000000000000060 R12: ffff964f82e70000
 R13: ffff964f81370c38 R14: ffffa737801d3dd3 R15: 0000000000000001
 FS:  0000000000000000(0000) GS:ffff9652bfd40000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000014 CR3: 000000008fa20004 CR4: 00000000003706e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  
  smc_llc_srv_rkey_exchange+0xa7/0x190 [smc]
  smc_llc_srv_add_link+0x3ae/0x5a0 [smc]
  smc_llc_add_link_work+0xb8/0x140 [smc]
  process_one_work+0x1e5/0x3f0
  worker_thread+0x4d/0x2f0
  ? __pfx_worker_thread+0x10/0x10
  kthread+0xe5/0x120
  ? __pfx_kthread+0x10/0x10
  ret_from_fork+0x2c/0x50
  

When an alernate RNIC is available in system, SMC will try to add a new
link based on the RNIC for resilience. All the RMBs in use will be mapped
to the new link. Then the RMBs' MRs corresponding to the new link will
be filled into LLC messages. For SMCRv1, they are ADD LINK CONT messages.

However smc_llc_add_link_cont() may mistakenly access to unused RMBs which
haven't been mapped to the new link and have no valid MRs, thus causing a
crash. So this patch fixes it.

Fixes: 87f88cda2128 ("net/smc: rkey processing for a new link as SMC client")
Link: https://lore.kernel.org/r/1685101741-74826-3-git-send-email-guwen@linux.alibaba.com
Signed-off-by: Wen Gu 
Reviewed-by: Wenjia Zhang 
Reviewed-by: Tony Lu 
Signed-off-by: David S. Miller

net/smc: Don't use RMBs not mapped to new link in SMCRv2 ADD LINK

2023-05-30T09:26:32+00:00

We encountered a crash when using SMCRv2. It is caused by a logical
error in smc_llc_fill_ext_v2().

 BUG: kernel NULL pointer dereference, address: 0000000000000014
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 7 PID: 453 Comm: kworker/7:4 Kdump: loaded Tainted: G        W   E      6.4.0-rc3+ #44
 Workqueue: events smc_llc_add_link_work [smc]
 RIP: 0010:smc_llc_fill_ext_v2+0x117/0x280 [smc]
 RSP: 0018:ffffacb5c064bd88 EFLAGS: 00010282
 RAX: ffff9a6bc1c3c02c RBX: ffff9a6be3558000 RCX: 0000000000000000
 RDX: 0000000000000002 RSI: 0000000000000002 RDI: 000000000000000a
 RBP: ffffacb5c064bdb8 R08: 0000000000000040 R09: 000000000000000c
 R10: ffff9a6bc0910300 R11: 0000000000000002 R12: 0000000000000000
 R13: 0000000000000002 R14: ffff9a6bc1c3c02c R15: ffff9a6be3558250
 FS:  0000000000000000(0000) GS:ffff9a6eefdc0000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000014 CR3: 000000010b078003 CR4: 00000000003706e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  
  smc_llc_send_add_link+0x1ae/0x2f0 [smc]
  smc_llc_srv_add_link+0x2c9/0x5a0 [smc]
  ? cc_mkenc+0x40/0x60
  smc_llc_add_link_work+0xb8/0x140 [smc]
  process_one_work+0x1e5/0x3f0
  worker_thread+0x4d/0x2f0
  ? __pfx_worker_thread+0x10/0x10
  kthread+0xe5/0x120
  ? __pfx_kthread+0x10/0x10
  ret_from_fork+0x2c/0x50
  

When an alernate RNIC is available in system, SMC will try to add a new
link based on the RNIC for resilience. All the RMBs in use will be mapped
to the new link. Then the RMBs' MRs corresponding to the new link will be
filled into SMCRv2 LLC ADD LINK messages.

However, smc_llc_fill_ext_v2() mistakenly accesses to unused RMBs which
haven't been mapped to the new link and have no valid MRs, thus causing
a crash. So this patch fixes the logic.

Fixes: b4ba4652b3f8 ("net/smc: extend LLC layer for SMC-Rv2")
Signed-off-by: Wen Gu 
Signed-off-by: Paolo Abeni

net/smc: Scan from current RMB list when no position specified

2023-05-30T09:26:32+00:00

When finding the first RMB of link group, it should start from the
current RMB list whose index is 0. So fix it.

Fixes: b4ba4652b3f8 ("net/smc: extend LLC layer for SMC-Rv2")
Signed-off-by: Wen Gu 
Signed-off-by: Paolo Abeni

net/smc: Reset connection when trying to use SMCRv2 fails.

2023-05-19T07:54:04+00:00

We found a crash when using SMCRv2 with 2 Mellanox ConnectX-4. It
can be reproduced by:

- smc_run nginx
- smc_run wrk -t 32 -c 500 -d 30 http://:

 BUG: kernel NULL pointer dereference, address: 0000000000000014
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 8000000108713067 P4D 8000000108713067 PUD 151127067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 4 PID: 2441 Comm: kworker/4:249 Kdump: loaded Tainted: G        W   E      6.4.0-rc1+ #42
 Workqueue: smc_hs_wq smc_listen_work [smc]
 RIP: 0010:smc_clc_send_confirm_accept+0x284/0x580 [smc]
 RSP: 0018:ffffb8294b2d7c78 EFLAGS: 00010a06
 RAX: ffff8f1873238880 RBX: ffffb8294b2d7dc8 RCX: 0000000000000000
 RDX: 00000000000000b4 RSI: 0000000000000001 RDI: 0000000000b40c00
 RBP: ffffb8294b2d7db8 R08: ffff8f1815c5860c R09: 0000000000000000
 R10: 0000000000000400 R11: 0000000000000000 R12: ffff8f1846f56180
 R13: ffff8f1815c5860c R14: 0000000000000001 R15: 0000000000000001
 FS:  0000000000000000(0000) GS:ffff8f1aefd00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000014 CR3: 00000001027a0001 CR4: 00000000003706e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  
  ? mlx5_ib_map_mr_sg+0xa1/0xd0 [mlx5_ib]
  ? smcr_buf_map_link+0x24b/0x290 [smc]
  ? __smc_buf_create+0x4ee/0x9b0 [smc]
  smc_clc_send_accept+0x4c/0xb0 [smc]
  smc_listen_work+0x346/0x650 [smc]
  ? __schedule+0x279/0x820
  process_one_work+0x1e5/0x3f0
  worker_thread+0x4d/0x2f0
  ? __pfx_worker_thread+0x10/0x10
  kthread+0xe5/0x120
  ? __pfx_kthread+0x10/0x10
  ret_from_fork+0x2c/0x50
  

During the CLC handshake, server sequentially tries available SMCRv2
and SMCRv1 devices in smc_listen_work().

If an SMCRv2 device is found. SMCv2 based link group and link will be
assigned to the connection. Then assumed that some buffer assignment
errors happen later in the CLC handshake, such as RMB registration
failure, server will give up SMCRv2 and try SMCRv1 device instead. But
the resources assigned to the connection won't be reset.

When server tries SMCRv1 device, the connection creation process will
be executed again. Since conn->lnk has been assigned when trying SMCRv2,
it will not be set to the correct SMCRv1 link in
smcr_lgr_conn_assign_link(). So in such situation, conn->lgr points to
correct SMCRv1 link group but conn->lnk points to the SMCRv2 link
mistakenly.

Then in smc_clc_send_confirm_accept(), conn->rmb_desc->mr[link->link_idx]
will be accessed. Since the link->link_idx is not correct, the related
MR may not have been initialized, so crash happens.

 | Try SMCRv2 device first
 |     |-> conn->lgr:	assign existed SMCRv2 link group;
 |     |-> conn->link:	assign existed SMCRv2 link (link_idx may be 1 in SMC_LGR_SYMMETRIC);
 |     |-> sndbuf & RMB creation fails, quit;
 |
 | Try SMCRv1 device then
 |     |-> conn->lgr:	create SMCRv1 link group and assign;
 |     |-> conn->link:	keep SMCRv2 link mistakenly;
 |     |-> sndbuf & RMB creation succeed, only RMB->mr[link_idx = 0]
 |         initialized.
 |
 | Then smc_clc_send_confirm_accept() accesses
 | conn->rmb_desc->mr[conn->link->link_idx, which is 1], then crash.
 v

This patch tries to fix this by cleaning conn->lnk before assigning
link. In addition, it is better to reset the connection and clean the
resources assigned if trying SMCRv2 failed in buffer creation or
registration.

Fixes: e49300a6bf62 ("net/smc: add listen processing for SMC-Rv2")
Link: https://lore.kernel.org/r/20220523055056.2078994-1-liuyacan@corp.netease.com/
Signed-off-by: Wen Gu 
Reviewed-by: Tony Lu 
Signed-off-by: David S. Miller

net: deal with most data-races in sk_wait_event()

2023-05-10T09:03:32+00:00

__condition is evaluated twice in sk_wait_event() macro.

First invocation is lockless, and reads can race with writes,
as spotted by syzbot.

BUG: KCSAN: data-race in sk_stream_wait_connect / tcp_disconnect

write to 0xffff88812d83d6a0 of 4 bytes by task 9065 on cpu 1:
tcp_disconnect+0x2cd/0xdb0
inet_shutdown+0x19e/0x1f0 net/ipv4/af_inet.c:911
__sys_shutdown_sock net/socket.c:2343 [inline]
__sys_shutdown net/socket.c:2355 [inline]
__do_sys_shutdown net/socket.c:2363 [inline]
__se_sys_shutdown+0xf8/0x140 net/socket.c:2361
__x64_sys_shutdown+0x31/0x40 net/socket.c:2361
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88812d83d6a0 of 4 bytes by task 9040 on cpu 0:
sk_stream_wait_connect+0x1de/0x3a0 net/core/stream.c:75
tcp_sendmsg_locked+0x2e4/0x2120 net/ipv4/tcp.c:1266
tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1484
inet6_sendmsg+0x63/0x80 net/ipv6/af_inet6.c:651
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
__sys_sendto+0x246/0x300 net/socket.c:2142
__do_sys_sendto net/socket.c:2154 [inline]
__se_sys_sendto net/socket.c:2150 [inline]
__x64_sys_sendto+0x78/0x90 net/socket.c:2150
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000 -> 0x00000068

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

Merge tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-04-28T02:42:02+00:00

Pull MM updates from Andrew Morton:

- Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
switching from a user process to a kernel thread.

- More folio conversions from Kefeng Wang, Zhang Peng and Pankaj
Raghav.

- zsmalloc performance improvements from Sergey Senozhatsky.

- Yue Zhao has found and fixed some data race issues around the
alteration of memcg userspace tunables.

- VFS rationalizations from Christoph Hellwig:
- removal of most of the callers of write_one_page()
- make __filemap_get_folio()'s return value more useful

- Luis Chamberlain has changed tmpfs so it no longer requires swap
backing. Use `mount -o noswap'.

- Qi Zheng has made the slab shrinkers operate locklessly, providing
some scalability benefits.

- Keith Busch has improved dmapool's performance, making part of its
operations O(1) rather than O(n).

- Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
permitting userspace to wr-protect anon memory unpopulated ptes.

- Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive
rather than exclusive, and has fixed a bunch of errors which were
caused by its unintuitive meaning.

- Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
which causes minor faults to install a write-protected pte.

- Vlastimil Babka has done some maintenance work on vma_merge():
cleanups to the kernel code and improvements to our userspace test
harness.

- Cleanups to do_fault_around() by Lorenzo Stoakes.

- Mike Rapoport has moved a lot of initialization code out of various
mm/ files and into mm/mm_init.c.

- Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
DRM, but DRM doesn't use it any more.

- Lorenzo has also coverted read_kcore() and vread() to use iterators
and has thereby removed the use of bounce buffers in some cases.

- Lorenzo has also contributed further cleanups of vma_merge().

- Chaitanya Prakash provides some fixes to the mmap selftesting code.

- Matthew Wilcox changes xfs and afs so they no longer take sleeping
locks in ->map_page(), a step towards RCUification of pagefaults.

- Suren Baghdasaryan has improved mmap_lock scalability by switching to
per-VMA locking.

- Frederic Weisbecker has reworked the percpu cache draining so that it
no longer causes latency glitches on cpu isolated workloads.

- Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
logic.

- Liu Shixin has changed zswap's initialization so we no longer waste a
chunk of memory if zswap is not being used.

- Yosry Ahmed has improved the performance of memcg statistics
flushing.

- David Stevens has fixed several issues involving khugepaged,
userfaultfd and shmem.

- Christoph Hellwig has provided some cleanup work to zram's IO-related
code paths.

- David Hildenbrand has fixed up some issues in the selftest code's
testing of our pte state changing.

- Pankaj Raghav has made page_endio() unneeded and has removed it.

- Peter Xu contributed some rationalizations of the userfaultfd
selftests.

- Yosry Ahmed has fixed an issue around memcg's page recalim
accounting.

- Chaitanya Prakash has fixed some arm-related issues in the
selftests/mm code.

- Longlong Xia has improved the way in which KSM handles hwpoisoned
pages.

- Peter Xu fixes a few issues with uffd-wp at fork() time.

- Stefan Roesch has changed KSM so that it may now be used on a
per-process and per-cgroup basis.

* tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
shmem: restrict noswap option to initial user namespace
mm/khugepaged: fix conflicting mods to collapse_file()
sparse: remove unnecessary 0 values from rc
mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
hugetlb: pte_alloc_huge() to replace huge pte_alloc_map()
maple_tree: fix allocation in mas_sparse_area()
mm: do not increment pgfault stats when page fault handler retries
zsmalloc: allow only one active pool compaction context
selftests/mm: add new selftests for KSM
mm: add new KSM process and sysfs knobs
mm: add new api to enable ksm per process
mm: shrinkers: fix debugfs file permissions
mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
migrate_pages_batch: fix statistics for longterm pin retry
userfaultfd: use helper function range_in_vma()
lib/show_mem.c: use for_each_populated_zone() simplify code
mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list()
fs/buffer: convert create_page_buffers to folio_create_buffers
fs/buffer: add folio_create_empty_buffers helper
...

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2023-04-13T23:04:28+00:00

Conflicts:

tools/testing/selftests/net/config
  62199e3f1658 ("selftests: net: Add VXLAN MDB test")
  3a0385be133e ("selftests: add the missing CONFIG_IP_SCTP in net config")

Signed-off-by: Jakub Kicinski

smc: Fix use-after-free in tcp_write_timer_handler().

2023-04-12T09:37:00+00:00

With Eric's ref tracker, syzbot finally found a repro for
use-after-free in tcp_write_timer_handler() by kernel TCP
sockets. [0]

If SMC creates a kernel socket in __smc_create(), the kernel
socket is supposed to be freed in smc_clcsock_release() by
calling sock_release() when we close() the parent SMC socket.

However, at the end of smc_clcsock_release(), the kernel
socket's sk_state might not be TCP_CLOSE.  This means that
we have not called inet_csk_destroy_sock() in __tcp_close()
and have not stopped the TCP timers.

The kernel socket's TCP timers can be fired later, so we
need to hold a refcnt for net as we do for MPTCP subflows
in mptcp_subflow_create_socket().

[0]:
leaked reference.
 sk_alloc (./include/net/net_namespace.h:335 net/core/sock.c:2108)
 inet_create (net/ipv4/af_inet.c:319 net/ipv4/af_inet.c:244)
 __sock_create (net/socket.c:1546)
 smc_create (net/smc/af_smc.c:3269 net/smc/af_smc.c:3284)
 __sock_create (net/socket.c:1546)
 __sys_socket (net/socket.c:1634 net/socket.c:1618 net/socket.c:1661)
 __x64_sys_socket (net/socket.c:1672)
 do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
==================================================================
BUG: KASAN: slab-use-after-free in tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594)
Read of size 1 at addr ffff888052b65e0d by task syzrepro/18091

CPU: 0 PID: 18091 Comm: syzrepro Tainted: G        W          6.3.0-rc4-01174-gb5d54eb5899a #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.amzn2022.0.1 04/01/2014
Call Trace:
 
 dump_stack_lvl (lib/dump_stack.c:107)
 print_report (mm/kasan/report.c:320 mm/kasan/report.c:430)
 kasan_report (mm/kasan/report.c:538)
 tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594)
 tcp_write_timer (./include/linux/spinlock.h:390 net/ipv4/tcp_timer.c:643)
 call_timer_fn (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/timer.h:127 kernel/time/timer.c:1701)
 __run_timers.part.0 (kernel/time/timer.c:1752 kernel/time/timer.c:2022)
 run_timer_softirq (kernel/time/timer.c:2037)
 __do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:572)
 __irq_exit_rcu (kernel/softirq.c:445 kernel/softirq.c:650)
 irq_exit_rcu (kernel/softirq.c:664)
 sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1107 (discriminator 14))
 

Fixes: ac7138746e14 ("smc: establish new socket family")
Reported-by: syzbot+7e1e1bdb852961150198@syzkaller.appspotmail.com
Link: https://lore.kernel.org/netdev/000000000000a3f51805f8bcc43a@google.com/
Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Tony Lu 
Signed-off-by: David S. Miller

mm, treewide: redefine MAX_ORDER sanely

2023-04-06T02:42:46+00:00

MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.

This definition is counter-intuitive and lead to number of bugs all over
the kernel.

Change the definition of MAX_ORDER to be inclusive: the range of orders
user can ask from buddy allocator is 0..MAX_ORDER now.

[kirill@shutemov.name: fix min() warning]
  Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box
[akpm@linux-foundation.org: fix another min_t warning]
[kirill@shutemov.name: fixups per Zi Yan]
  Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name
[akpm@linux-foundation.org: fix underlining in docs]
  Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/
Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov 
Reviewed-by: Michael Ellerman 	[powerpc]
Cc: "Kirill A. Shutemov" 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

smc: preserve const qualifier in smc_sk()

2023-03-18T12:23:33+00:00

We can change smc_sk() to propagate its argument const qualifier,
thanks to container_of_const().

Signed-off-by: Eric Dumazet 
Cc: Karsten Graul 
Cc: Wenjia Zhang 
Cc: Jan Karcher 
Reviewed-by: Simon Horman 
Reviewed-by: Wenjia Zhang 
Signed-off-by: David S. Miller