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Support CONFIG_MMU=n #87

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jimwang99 opened this issue Sep 27, 2017 · 3 comments
Open

Support CONFIG_MMU=n #87

jimwang99 opened this issue Sep 27, 2017 · 3 comments

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@jimwang99
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Hi,

If we don't support virtual memory in RISC-V, can we still use riscv-linux? Is there any switch while compiling Linux kernel to support non-virtual memory CPU?

Thank you.

Jim

@palmer-dabbelt
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We don't currently have a no-MMU Linux port for RISC-V. While it would be possible to build one, it's a big chunk of work and to the best of my knowledge nobody is working on it. If you're interested in working on the port then I can try to help out, but otherwise I don't see it happening any time soon.

@palmer-dabbelt palmer-dabbelt changed the title Port Linux to non-virtual memory CPU Support CONFIG_MMU=n Nov 16, 2017
palmer-dabbelt pushed a commit that referenced this issue Dec 27, 2017
…nk leaks

The early call to br_stp_change_bridge_id in bridge's newlink can cause
a memory leak if an error occurs during the newlink because the fdb
entries are not cleaned up if a different lladdr was specified, also
another minor issue is that it generates fdb notifications with
ifindex = 0. Another unrelated memory leak is the bridge sysfs entries
which get added on NETDEV_REGISTER event, but are not cleaned up in the
newlink error path. To remove this special case the call to
br_stp_change_bridge_id is done after netdev register and we cleanup the
bridge on changelink error via br_dev_delete to plug all leaks.

This patch makes netlink bridge destruction on newlink error the same as
dellink and ioctl del which is necessary since at that point we have a
fully initialized bridge device.

To reproduce the issue:
$ ip l add br0 address 00:11:22:33:44:55 type bridge group_fwd_mask 1
RTNETLINK answers: Invalid argument

$ rmmod bridge
[ 1822.142525] =============================================================================
[ 1822.143640] BUG bridge_fdb_cache (Tainted: G           O    ): Objects remaining in bridge_fdb_cache on __kmem_cache_shutdown()
[ 1822.144821] -----------------------------------------------------------------------------

[ 1822.145990] Disabling lock debugging due to kernel taint
[ 1822.146732] INFO: Slab 0x0000000092a844b2 objects=32 used=2 fp=0x00000000fef011b0 flags=0x1ffff8000000100
[ 1822.147700] CPU: 2 PID: 13584 Comm: rmmod Tainted: G    B      O     4.15.0-rc2+ #87
[ 1822.148578] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 1822.150008] Call Trace:
[ 1822.150510]  dump_stack+0x78/0xa9
[ 1822.151156]  slab_err+0xb1/0xd3
[ 1822.151834]  ? __kmalloc+0x1bb/0x1ce
[ 1822.152546]  __kmem_cache_shutdown+0x151/0x28b
[ 1822.153395]  shutdown_cache+0x13/0x144
[ 1822.154126]  kmem_cache_destroy+0x1c0/0x1fb
[ 1822.154669]  SyS_delete_module+0x194/0x244
[ 1822.155199]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[ 1822.155773]  entry_SYSCALL_64_fastpath+0x23/0x9a
[ 1822.156343] RIP: 0033:0x7f929bd38b17
[ 1822.156859] RSP: 002b:00007ffd160e9a98 EFLAGS: 00000202 ORIG_RAX: 00000000000000b0
[ 1822.157728] RAX: ffffffffffffffda RBX: 00005578316ba090 RCX: 00007f929bd38b17
[ 1822.158422] RDX: 00007f929bd9ec60 RSI: 0000000000000800 RDI: 00005578316ba0f0
[ 1822.159114] RBP: 0000000000000003 R08: 00007f929bff5f20 R09: 00007ffd160e8a11
[ 1822.159808] R10: 00007ffd160e9860 R11: 0000000000000202 R12: 00007ffd160e8a80
[ 1822.160513] R13: 0000000000000000 R14: 0000000000000000 R15: 00005578316ba090
[ 1822.161278] INFO: Object 0x000000007645de29 @offset=0
[ 1822.161666] INFO: Object 0x00000000d5df2ab5 @offset=128

Fixes: 30313a3 ("bridge: Handle IFLA_ADDRESS correctly when creating bridge device")
Fixes: 5b8d542 ("bridge: netlink: register netdevice before executing changelink")
Signed-off-by: Nikolay Aleksandrov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
palmer-dabbelt pushed a commit that referenced this issue Feb 26, 2018
There is no matching lock for this mutex. Git history suggests this is
just a missed remnant from an earlier version of the function before
this locking was moved into uverbs_free_xrcd.

Originally this lock was protecting the xrcd_table_delete()

=====================================
WARNING: bad unlock balance detected!
4.15.0+ #87 Not tainted
-------------------------------------
syzkaller223405/269 is trying to release lock (&uverbs_dev->xrcd_tree_mutex) at:
[<00000000b8703372>] ib_uverbs_close_xrcd+0x195/0x1f0
but there are no more locks to release!

other info that might help us debug this:
1 lock held by syzkaller223405/269:
 #0:  (&uverbs_dev->disassociate_srcu){....}, at: [<000000005af3b960>] ib_uverbs_write+0x265/0xef0

stack backtrace:
CPU: 0 PID: 269 Comm: syzkaller223405 Not tainted 4.15.0+ #87
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
Call Trace:
 dump_stack+0xde/0x164
 ? dma_virt_map_sg+0x22c/0x22c
 ? ib_uverbs_write+0x265/0xef0
 ? console_unlock+0x502/0xbd0
 ? ib_uverbs_close_xrcd+0x195/0x1f0
 print_unlock_imbalance_bug+0x131/0x160
 lock_release+0x59d/0x1100
 ? ib_uverbs_close_xrcd+0x195/0x1f0
 ? lock_acquire+0x440/0x440
 ? lock_acquire+0x440/0x440
 __mutex_unlock_slowpath+0x88/0x670
 ? wait_for_completion+0x4c0/0x4c0
 ? rdma_lookup_get_uobject+0x145/0x2f0
 ib_uverbs_close_xrcd+0x195/0x1f0
 ? ib_uverbs_open_xrcd+0xdd0/0xdd0
 ib_uverbs_write+0x7f9/0xef0
 ? cyc2ns_read_end+0x10/0x10
 ? ib_uverbs_open_xrcd+0xdd0/0xdd0
 ? uverbs_devnode+0x110/0x110
 ? cyc2ns_read_end+0x10/0x10
 ? cyc2ns_read_end+0x10/0x10
 ? sched_clock_cpu+0x18/0x200
 __vfs_write+0x10d/0x700
 ? uverbs_devnode+0x110/0x110
 ? kernel_read+0x170/0x170
 ? __fget+0x358/0x5d0
 ? security_file_permission+0x93/0x260
 vfs_write+0x1b0/0x550
 SyS_write+0xc7/0x1a0
 ? SyS_read+0x1a0/0x1a0
 ? trace_hardirqs_on_thunk+0x1a/0x1c
 entry_SYSCALL_64_fastpath+0x1e/0x8b
RIP: 0033:0x4335c9

Cc: syzkaller <[email protected]>
Cc: <[email protected]> # 4.11
Fixes: fd3c790 ("IB/core: Change idr objects to use the new schema")
Reported-by: Noa Osherovich <[email protected]>
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
palmer-dabbelt pushed a commit that referenced this issue Feb 26, 2018
Avoid circular locking dependency by calling
to uobj_alloc_commit() outside of xrcd_tree_mutex lock.

======================================================
WARNING: possible circular locking dependency detected
4.15.0+ #87 Not tainted
------------------------------------------------------
syzkaller401056/269 is trying to acquire lock:
 (&uverbs_dev->xrcd_tree_mutex){+.+.}, at: [<000000006c12d2cd>] uverbs_free_xrcd+0xd2/0x360

but task is already holding lock:
 (&ucontext->uobjects_lock){+.+.}, at: [<00000000da010f09>] uverbs_cleanup_ucontext+0x168/0x730

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&ucontext->uobjects_lock){+.+.}:
       __mutex_lock+0x111/0x1720
       rdma_alloc_commit_uobject+0x22c/0x600
       ib_uverbs_open_xrcd+0x61a/0xdd0
       ib_uverbs_write+0x7f9/0xef0
       __vfs_write+0x10d/0x700
       vfs_write+0x1b0/0x550
       SyS_write+0xc7/0x1a0
       entry_SYSCALL_64_fastpath+0x1e/0x8b

-> #0 (&uverbs_dev->xrcd_tree_mutex){+.+.}:
       lock_acquire+0x19d/0x440
       __mutex_lock+0x111/0x1720
       uverbs_free_xrcd+0xd2/0x360
       remove_commit_idr_uobject+0x6d/0x110
       uverbs_cleanup_ucontext+0x2f0/0x730
       ib_uverbs_cleanup_ucontext.constprop.3+0x52/0x120
       ib_uverbs_close+0xf2/0x570
       __fput+0x2cd/0x8d0
       task_work_run+0xec/0x1d0
       do_exit+0x6a1/0x1520
       do_group_exit+0xe8/0x380
       SyS_exit_group+0x1e/0x20
       entry_SYSCALL_64_fastpath+0x1e/0x8b

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ucontext->uobjects_lock);
                               lock(&uverbs_dev->xrcd_tree_mutex);
                               lock(&ucontext->uobjects_lock);
  lock(&uverbs_dev->xrcd_tree_mutex);

 *** DEADLOCK ***

3 locks held by syzkaller401056/269:
 #0:  (&file->cleanup_mutex){+.+.}, at: [<00000000c9f0c252>] ib_uverbs_close+0xac/0x570
 #1:  (&ucontext->cleanup_rwsem){++++}, at: [<00000000b6994d49>] uverbs_cleanup_ucontext+0xf6/0x730
 #2:  (&ucontext->uobjects_lock){+.+.}, at: [<00000000da010f09>] uverbs_cleanup_ucontext+0x168/0x730

stack backtrace:
CPU: 0 PID: 269 Comm: syzkaller401056 Not tainted 4.15.0+ #87
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
Call Trace:
 dump_stack+0xde/0x164
 ? dma_virt_map_sg+0x22c/0x22c
 ? uverbs_cleanup_ucontext+0x168/0x730
 ? console_unlock+0x502/0xbd0
 print_circular_bug.isra.24+0x35e/0x396
 ? print_circular_bug_header+0x12e/0x12e
 ? find_usage_backwards+0x30/0x30
 ? entry_SYSCALL_64_fastpath+0x1e/0x8b
 validate_chain.isra.28+0x25d1/0x40c0
 ? check_usage+0xb70/0xb70
 ? graph_lock+0x160/0x160
 ? find_usage_backwards+0x30/0x30
 ? cyc2ns_read_end+0x10/0x10
 ? print_irqtrace_events+0x280/0x280
 ? __lock_acquire+0x93d/0x1630
 __lock_acquire+0x93d/0x1630
 lock_acquire+0x19d/0x440
 ? uverbs_free_xrcd+0xd2/0x360
 __mutex_lock+0x111/0x1720
 ? uverbs_free_xrcd+0xd2/0x360
 ? uverbs_free_xrcd+0xd2/0x360
 ? __mutex_lock+0x828/0x1720
 ? mutex_lock_io_nested+0x1550/0x1550
 ? uverbs_cleanup_ucontext+0x168/0x730
 ? __lock_acquire+0x9a9/0x1630
 ? mutex_lock_io_nested+0x1550/0x1550
 ? uverbs_cleanup_ucontext+0xf6/0x730
 ? lock_contended+0x11a0/0x11a0
 ? uverbs_free_xrcd+0xd2/0x360
 uverbs_free_xrcd+0xd2/0x360
 remove_commit_idr_uobject+0x6d/0x110
 uverbs_cleanup_ucontext+0x2f0/0x730
 ? sched_clock_cpu+0x18/0x200
 ? uverbs_close_fd+0x1c0/0x1c0
 ib_uverbs_cleanup_ucontext.constprop.3+0x52/0x120
 ib_uverbs_close+0xf2/0x570
 ? ib_uverbs_remove_one+0xb50/0xb50
 ? ib_uverbs_remove_one+0xb50/0xb50
 __fput+0x2cd/0x8d0
 task_work_run+0xec/0x1d0
 do_exit+0x6a1/0x1520
 ? fsnotify_first_mark+0x220/0x220
 ? exit_notify+0x9f0/0x9f0
 ? entry_SYSCALL_64_fastpath+0x5/0x8b
 ? entry_SYSCALL_64_fastpath+0x5/0x8b
 ? trace_hardirqs_on_thunk+0x1a/0x1c
 ? time_hardirqs_on+0x27/0x670
 ? time_hardirqs_off+0x27/0x490
 ? syscall_return_slowpath+0x6c/0x460
 ? entry_SYSCALL_64_fastpath+0x5/0x8b
 do_group_exit+0xe8/0x380
 SyS_exit_group+0x1e/0x20
 entry_SYSCALL_64_fastpath+0x1e/0x8b
RIP: 0033:0x431ce9

Cc: syzkaller <[email protected]>
Cc: <[email protected]> # 4.11
Fixes: fd3c790 ("IB/core: Change idr objects to use the new schema")
Reported-by: Noa Osherovich <[email protected]>
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
palmer-dabbelt pushed a commit that referenced this issue May 14, 2018
syzbot/KMSAN reported an uninit-value in ip6_multipath_l3_keys(),
root caused to a bad assumption of ICMP header being already
pulled in skb->head

ip_multipath_l3_keys() does the correct thing, so it is an IPv6 only bug.

BUG: KMSAN: uninit-value in ip6_multipath_l3_keys net/ipv6/route.c:1830 [inline]
BUG: KMSAN: uninit-value in rt6_multipath_hash+0x5c4/0x640 net/ipv6/route.c:1858
CPU: 0 PID: 4507 Comm: syz-executor661 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 ip6_multipath_l3_keys net/ipv6/route.c:1830 [inline]
 rt6_multipath_hash+0x5c4/0x640 net/ipv6/route.c:1858
 ip6_route_input+0x65a/0x920 net/ipv6/route.c:1884
 ip6_rcv_finish+0x413/0x6e0 net/ipv6/ip6_input.c:69
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ipv6_rcv+0x1e16/0x2340 net/ipv6/ip6_input.c:208
 __netif_receive_skb_core+0x47df/0x4a90 net/core/dev.c:4562
 __netif_receive_skb net/core/dev.c:4627 [inline]
 netif_receive_skb_internal+0x49d/0x630 net/core/dev.c:4701
 netif_receive_skb+0x230/0x240 net/core/dev.c:4725
 tun_rx_batched drivers/net/tun.c:1555 [inline]
 tun_get_user+0x740f/0x7c60 drivers/net/tun.c:1962
 tun_chr_write_iter+0x1d4/0x330 drivers/net/tun.c:1990
 call_write_iter include/linux/fs.h:1782 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x7fb/0x9f0 fs/read_write.c:482
 vfs_write+0x463/0x8d0 fs/read_write.c:544
 SYSC_write+0x172/0x360 fs/read_write.c:589
 SyS_write+0x55/0x80 fs/read_write.c:581
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Fixes: 23aebda ("ipv6: Compute multipath hash for ICMP errors from offending packet")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Cc: Jakub Sitnicki <[email protected]>
Acked-by: Jakub Sitnicki <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
palmer-dabbelt pushed a commit that referenced this issue May 14, 2018
syzbot/KMSAN reported an uninit-value in put_cmsg(), originating
from rds_cmsg_recv().

Simply clear the structure, since we have holes there, or since
rx_traces might be smaller than RDS_MSG_RX_DGRAM_TRACE_MAX.

BUG: KMSAN: uninit-value in copy_to_user include/linux/uaccess.h:184 [inline]
BUG: KMSAN: uninit-value in put_cmsg+0x600/0x870 net/core/scm.c:242
CPU: 0 PID: 4459 Comm: syz-executor582 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 kmsan_internal_check_memory+0x135/0x1e0 mm/kmsan/kmsan.c:1157
 kmsan_copy_to_user+0x69/0x160 mm/kmsan/kmsan.c:1199
 copy_to_user include/linux/uaccess.h:184 [inline]
 put_cmsg+0x600/0x870 net/core/scm.c:242
 rds_cmsg_recv net/rds/recv.c:570 [inline]
 rds_recvmsg+0x2db5/0x3170 net/rds/recv.c:657
 sock_recvmsg_nosec net/socket.c:803 [inline]
 sock_recvmsg+0x1d0/0x230 net/socket.c:810
 ___sys_recvmsg+0x3fb/0x810 net/socket.c:2205
 __sys_recvmsg net/socket.c:2250 [inline]
 SYSC_recvmsg+0x298/0x3c0 net/socket.c:2262
 SyS_recvmsg+0x54/0x80 net/socket.c:2257
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Fixes: 3289025 ("RDS: add receive message trace used by application")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Cc: Santosh Shilimkar <[email protected]>
Cc: linux-rdma <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
palmer-dabbelt pushed a commit that referenced this issue May 14, 2018
When we get link properties through netlink interface with
tipc_nl_node_get_link(), we don't validate TIPC_NLA_LINK_NAME
attribute at all, instead we directly use it. As a consequence,
KMSAN detected the TIPC_NLA_LINK_NAME attribute was an uninitialized
value, and then posted the following complaint:

==================================================================
BUG: KMSAN: uninit-value in strcmp+0xf7/0x160 lib/string.c:329
CPU: 1 PID: 4527 Comm: syz-executor655 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x185/0x1d0 lib/dump_stack.c:53
  kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
  __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
  strcmp+0xf7/0x160 lib/string.c:329
  tipc_nl_node_get_link+0x220/0x6f0 net/tipc/node.c:1881
  genl_family_rcv_msg net/netlink/genetlink.c:599 [inline]
  genl_rcv_msg+0x1686/0x1810 net/netlink/genetlink.c:624
  netlink_rcv_skb+0x378/0x600 net/netlink/af_netlink.c:2447
  genl_rcv+0x63/0x80 net/netlink/genetlink.c:635
  netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
  netlink_unicast+0x166b/0x1740 net/netlink/af_netlink.c:1337
  netlink_sendmsg+0x1048/0x1310 net/netlink/af_netlink.c:1900
  sock_sendmsg_nosec net/socket.c:630 [inline]
  sock_sendmsg net/socket.c:640 [inline]
  ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
  __sys_sendmsg net/socket.c:2080 [inline]
  SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
  SyS_sendmsg+0x54/0x80 net/socket.c:2087
  do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x445589
RSP: 002b:00007fb7ee66cdb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 0000000000445589
RDX: 0000000000000000 RSI: 0000000020023000 RDI: 0000000000000003
RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffa2bf3f3f R14: 00007fb7ee66d9c0 R15: 0000000000000001

Uninit was created at:
  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
  kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
  kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
  kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
  slab_post_alloc_hook mm/slab.h:445 [inline]
  slab_alloc_node mm/slub.c:2737 [inline]
  __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
  __kmalloc_reserve net/core/skbuff.c:138 [inline]
  __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
  alloc_skb include/linux/skbuff.h:984 [inline]
  netlink_alloc_large_skb net/netlink/af_netlink.c:1183 [inline]
  netlink_sendmsg+0x9a6/0x1310 net/netlink/af_netlink.c:1875
  sock_sendmsg_nosec net/socket.c:630 [inline]
  sock_sendmsg net/socket.c:640 [inline]
  ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
  __sys_sendmsg net/socket.c:2080 [inline]
  SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
  SyS_sendmsg+0x54/0x80 net/socket.c:2087
  do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
==================================================================

To quiet the complaint, TIPC_NLA_LINK_NAME attribute has been
validated in tipc_nl_node_get_link() before it's used.

Reported-by: [email protected]
Signed-off-by: Ying Xue <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
@haizzus
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haizzus commented Jun 1, 2018

@palmer-dabbelt I'm interested and considering spending a few hours a week on this. How do I contact you (email/slack ?) to discuss further?

@palmer-dabbelt
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Contributor

#riscv on freednode or [email protected] are the best bets -- Linux is open source and there's people who aren't just me working on it, so there you'll find everyone.

atishp04 pushed a commit to atishp04/riscv-linux that referenced this issue Aug 29, 2018
palmer-dabbelt pushed a commit that referenced this issue Sep 26, 2018
pppoe_rcv() needs to look back at the Ethernet header in order to
lookup the PPPoE session. Therefore we need to ensure that the mac
header is big enough to contain an Ethernet header. Otherwise
eth_hdr(skb)->h_source might access invalid data.

==================================================================
BUG: KMSAN: uninit-value in __get_item drivers/net/ppp/pppoe.c:172 [inline]
BUG: KMSAN: uninit-value in get_item drivers/net/ppp/pppoe.c:236 [inline]
BUG: KMSAN: uninit-value in pppoe_rcv+0xcef/0x10e0 drivers/net/ppp/pppoe.c:450
CPU: 0 PID: 4543 Comm: syz-executor355 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 __get_item drivers/net/ppp/pppoe.c:172 [inline]
 get_item drivers/net/ppp/pppoe.c:236 [inline]
 pppoe_rcv+0xcef/0x10e0 drivers/net/ppp/pppoe.c:450
 __netif_receive_skb_core+0x47df/0x4a90 net/core/dev.c:4562
 __netif_receive_skb net/core/dev.c:4627 [inline]
 netif_receive_skb_internal+0x49d/0x630 net/core/dev.c:4701
 netif_receive_skb+0x230/0x240 net/core/dev.c:4725
 tun_rx_batched drivers/net/tun.c:1555 [inline]
 tun_get_user+0x740f/0x7c60 drivers/net/tun.c:1962
 tun_chr_write_iter+0x1d4/0x330 drivers/net/tun.c:1990
 call_write_iter include/linux/fs.h:1782 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x7fb/0x9f0 fs/read_write.c:482
 vfs_write+0x463/0x8d0 fs/read_write.c:544
 SYSC_write+0x172/0x360 fs/read_write.c:589
 SyS_write+0x55/0x80 fs/read_write.c:581
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x4447c9
RSP: 002b:00007fff64c8fc28 EFLAGS: 00000297 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004447c9
RDX: 000000000000fd87 RSI: 0000000020000600 RDI: 0000000000000004
RBP: 00000000006cf018 R08: 00007fff64c8fda8 R09: 00007fff00006bda
R10: 0000000000005fe7 R11: 0000000000000297 R12: 00000000004020d0
R13: 0000000000402160 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
 slab_post_alloc_hook mm/slab.h:445 [inline]
 slab_alloc_node mm/slub.c:2737 [inline]
 __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:984 [inline]
 alloc_skb_with_frags+0x1d4/0xb20 net/core/skbuff.c:5234
 sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2085
 tun_alloc_skb drivers/net/tun.c:1532 [inline]
 tun_get_user+0x2242/0x7c60 drivers/net/tun.c:1829
 tun_chr_write_iter+0x1d4/0x330 drivers/net/tun.c:1990
 call_write_iter include/linux/fs.h:1782 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x7fb/0x9f0 fs/read_write.c:482
 vfs_write+0x463/0x8d0 fs/read_write.c:544
 SYSC_write+0x172/0x360 fs/read_write.c:589
 SyS_write+0x55/0x80 fs/read_write.c:581
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
==================================================================

Fixes: 224cf5a ("ppp: Move the PPP drivers")
Reported-by: [email protected]
Signed-off-by: Guillaume Nault <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
palmer-dabbelt pushed a commit that referenced this issue Oct 2, 2018
the ip6 tunnel xmit ndo assumes that the processed skb always
contains an ip[v6] header, but syzbot has found a way to send
frames that fall short of this assumption, leading to the following splat:

BUG: KMSAN: uninit-value in ip6ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1307
[inline]
BUG: KMSAN: uninit-value in ip6_tnl_start_xmit+0x7d2/0x1ef0
net/ipv6/ip6_tunnel.c:1390
CPU: 0 PID: 4504 Comm: syz-executor558 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x185/0x1d0 lib/dump_stack.c:53
  kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
  __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
  ip6ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1307 [inline]
  ip6_tnl_start_xmit+0x7d2/0x1ef0 net/ipv6/ip6_tunnel.c:1390
  __netdev_start_xmit include/linux/netdevice.h:4066 [inline]
  netdev_start_xmit include/linux/netdevice.h:4075 [inline]
  xmit_one net/core/dev.c:3026 [inline]
  dev_hard_start_xmit+0x5f1/0xc70 net/core/dev.c:3042
  __dev_queue_xmit+0x27ee/0x3520 net/core/dev.c:3557
  dev_queue_xmit+0x4b/0x60 net/core/dev.c:3590
  packet_snd net/packet/af_packet.c:2944 [inline]
  packet_sendmsg+0x7c70/0x8a30 net/packet/af_packet.c:2969
  sock_sendmsg_nosec net/socket.c:630 [inline]
  sock_sendmsg net/socket.c:640 [inline]
  ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
  __sys_sendmmsg+0x42d/0x800 net/socket.c:2136
  SYSC_sendmmsg+0xc4/0x110 net/socket.c:2167
  SyS_sendmmsg+0x63/0x90 net/socket.c:2162
  do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x441819
RSP: 002b:00007ffe58ee8268 EFLAGS: 00000213 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441819
RDX: 0000000000000002 RSI: 0000000020000100 RDI: 0000000000000003
RBP: 00000000006cd018 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000402510
R13: 00000000004025a0 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
  kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
  kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
  kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
  slab_post_alloc_hook mm/slab.h:445 [inline]
  slab_alloc_node mm/slub.c:2737 [inline]
  __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
  __kmalloc_reserve net/core/skbuff.c:138 [inline]
  __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
  alloc_skb include/linux/skbuff.h:984 [inline]
  alloc_skb_with_frags+0x1d4/0xb20 net/core/skbuff.c:5234
  sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2085
  packet_alloc_skb net/packet/af_packet.c:2803 [inline]
  packet_snd net/packet/af_packet.c:2894 [inline]
  packet_sendmsg+0x6454/0x8a30 net/packet/af_packet.c:2969
  sock_sendmsg_nosec net/socket.c:630 [inline]
  sock_sendmsg net/socket.c:640 [inline]
  ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
  __sys_sendmmsg+0x42d/0x800 net/socket.c:2136
  SYSC_sendmmsg+0xc4/0x110 net/socket.c:2167
  SyS_sendmmsg+0x63/0x90 net/socket.c:2162
  do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x3d/0xa2

This change addresses the issue adding the needed check before
accessing the inner header.

The ipv4 side of the issue is apparently there since the ipv4 over ipv6
initial support, and the ipv6 side predates git history.

Fixes: c4d3efa ("[IPV6] IP6TUNNEL: Add support to IPv4 over IPv6 tunnel.")
Fixes: 1da177e ("Linux-2.6.12-rc2")
Reported-by: [email protected]
Tested-by: Alexander Potapenko <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
atishp04 pushed a commit to atishp04/riscv-linux that referenced this issue Feb 6, 2019
cpuinfo_cur_freq gets current CPU frequency as detected by hardware
while scaling_cur_freq last known CPU frequency. Some platforms may not
allow checking the CPU frequency of an offline CPU or the associated
resources may have been released via cpufreq_exit when the CPU gets
offlined, in which case the policy would have been invalidated already.
If we attempt to get current frequency from the hardware, it may result
in hang or crash.

For example on Juno, I see:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000188
[0000000000000188] pgd=0000000000000000
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 5 PID: 4202 Comm: cat Not tainted 4.20.0-08251-ga0f2c0318a15-dirty riscvarchive#87
Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform
pstate: 40000005 (nZcv daif -PAN -UAO)
pc : scmi_cpufreq_get_rate+0x34/0xb0
lr : scmi_cpufreq_get_rate+0x34/0xb0
Call trace:
 scmi_cpufreq_get_rate+0x34/0xb0
 __cpufreq_get+0x34/0xc0
 show_cpuinfo_cur_freq+0x24/0x78
 show+0x40/0x60
 sysfs_kf_seq_show+0xc0/0x148
 kernfs_seq_show+0x44/0x50
 seq_read+0xd4/0x480
 kernfs_fop_read+0x15c/0x208
 __vfs_read+0x60/0x188
 vfs_read+0x94/0x150
 ksys_read+0x6c/0xd8
 __arm64_sys_read+0x24/0x30
 el0_svc_common+0x78/0x100
 el0_svc_handler+0x38/0x78
 el0_svc+0x8/0xc
---[ end trace 3d1024e58f77f6b2 ]---

So fix the issue by checking if the policy is invalid early in
__cpufreq_get before attempting to get the current frequency.

Signed-off-by: Sudeep Holla <[email protected]>
Acked-by: Viresh Kumar <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
atishp04 pushed a commit to atishp04/riscv-linux that referenced this issue Feb 6, 2019
BUG: KMSAN: uninit-value in tipc_nl_compat_doit+0x404/0xa10 net/tipc/netlink_compat.c:335
CPU: 0 PID: 4514 Comm: syz-executor485 Not tainted 4.16.0+ riscvarchive#87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 tipc_nl_compat_doit+0x404/0xa10 net/tipc/netlink_compat.c:335
 tipc_nl_compat_recv+0x164b/0x2700 net/tipc/netlink_compat.c:1153
 genl_family_rcv_msg net/netlink/genetlink.c:599 [inline]
 genl_rcv_msg+0x1686/0x1810 net/netlink/genetlink.c:624
 netlink_rcv_skb+0x378/0x600 net/netlink/af_netlink.c:2447
 genl_rcv+0x63/0x80 net/netlink/genetlink.c:635
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x166b/0x1740 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0x1048/0x1310 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
 __sys_sendmsg net/socket.c:2080 [inline]
 SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
 SyS_sendmsg+0x54/0x80 net/socket.c:2087
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x43fda9
RSP: 002b:00007ffd0c184ba8 EFLAGS: 00000213 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fda9
RDX: 0000000000000000 RSI: 0000000020023000 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000213 R12: 00000000004016d0
R13: 0000000000401760 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
 slab_post_alloc_hook mm/slab.h:445 [inline]
 slab_alloc_node mm/slub.c:2737 [inline]
 __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:984 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1183 [inline]
 netlink_sendmsg+0x9a6/0x1310 net/netlink/af_netlink.c:1875
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
 __sys_sendmsg net/socket.c:2080 [inline]
 SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
 SyS_sendmsg+0x54/0x80 net/socket.c:2087
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

In tipc_nl_compat_recv(), when the len variable returned by
nlmsg_attrlen() is 0, the message is still treated as a valid one,
which is obviously unresonable. When len is zero, it means the
message not only doesn't contain any valid TLV payload, but also
TLV header is not included. Under this stituation, tlv_type field
in TLV header is still accessed in tipc_nl_compat_dumpit() or
tipc_nl_compat_doit(), but the field space is obviously illegal.
Of course, it is not initialized.

Reported-by: [email protected]
Reported-by: [email protected]
Signed-off-by: Ying Xue <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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