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llvm-objcopy doesn't support wildcards #616

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nickdesaulniers opened this issue Jul 21, 2019 · 7 comments
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llvm-objcopy doesn't support wildcards #616

nickdesaulniers opened this issue Jul 21, 2019 · 7 comments
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@nickdesaulniers
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based on ClangBuiltLinux/continuous-integration#183 (comment) @nathanchance mentioned that arm64 4.4 builds fail due to missing wildcard support. We should file a bug in upstream llvm's issue tracker if there's not one already, then see why this is 4.4 specific? Maybe there's a backport we can send to stable. cc @rupprecht
@nickdesaulniers nickdesaulniers added [BUG] llvm A bug that should be fixed in upstream LLVM [ARCH] arm64 This bug impacts ARCH=arm64 Needs Backport Should be backported to either linux-stable tree or latest llvm release branch. [TOOL] llvm-objcopy The issue is relevant to LLVM objcopy labels Jul 21, 2019
@nathanchance
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nathanchance commented Jul 21, 2019 •
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https://llvm.org/pr41268

#478 (comment)

@nickdesaulniers
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wouldn't the backports simply be:

  1. 696204f#diff-a293b6e43601de50c3660edbde6b4bde
  2. 02562d0#diff-a293b6e43601de50c3660edbde6b4bde

@nathanchance
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Pretty sure that I tried those and the conflicts were fairly invasive... Don't quite recall though. I'll try to revisit this in the next couple of days.

@tpimh
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tpimh commented Jul 21, 2019

Maybe we can check for objcopy support for regexes and if they are supported, use regexes instead of globs? Or maybe even take it one step further and write a function that converts globs to regexes.

@nathanchance
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I just revisited the backports now.

  1. 696204f depends on 81a0bc3 but that doesn't appear to matter for arm64.

  2. 02562d0 depends on f922c4a which in turn depends on at least f235541, e4aca45, and c1a95fd. I see what appear to be several follow up fixes so I think this is all too invasive for a stable backport.

@tpimh tpimh mentioned this issue Sep 4, 2019
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@nickdesaulniers
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nickdesaulniers commented Oct 17, 2019 •
edited by nathanchance
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Progress: https://llvm.org/pr41268

@nickdesaulniers
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dup #478

@nickdesaulniers nickdesaulniers added duplicate This issue or pull request already exists and removed Needs Backport Should be backported to either linux-stable tree or latest llvm release branch. [ARCH] arm64 This bug impacts ARCH=arm64 [BUG] llvm A bug that should be fixed in upstream LLVM [TOOL] llvm-objcopy The issue is relevant to LLVM objcopy labels Oct 17, 2019
nathanchance pushed a commit that referenced this issue Jun 26, 2020
@TaeheeYoo @davem330
ip_tunnel: fix use-after-free in ip_tunnel_lookup()
ba61539 
In the datapath, the ip_tunnel_lookup() is used and it internally uses
fallback tunnel device pointer, which is fb_tunnel_dev.
This pointer variable should be set to NULL when a fb interface is deleted.
But there is no routine to set fb_tunnel_dev pointer to NULL.
So, this pointer will be still used after interface is deleted and
it eventually results in the use-after-free problem.

Test commands:
    ip netns add A
    ip netns add B
    ip link add eth0 type veth peer name eth1
    ip link set eth0 netns A
    ip link set eth1 netns B

    ip netns exec A ip link set lo up
    ip netns exec A ip link set eth0 up
    ip netns exec A ip link add gre1 type gre local 10.0.0.1 \
	    remote 10.0.0.2
    ip netns exec A ip link set gre1 up
    ip netns exec A ip a a 10.0.100.1/24 dev gre1
    ip netns exec A ip a a 10.0.0.1/24 dev eth0

    ip netns exec B ip link set lo up
    ip netns exec B ip link set eth1 up
    ip netns exec B ip link add gre1 type gre local 10.0.0.2 \
	    remote 10.0.0.1
    ip netns exec B ip link set gre1 up
    ip netns exec B ip a a 10.0.100.2/24 dev gre1
    ip netns exec B ip a a 10.0.0.2/24 dev eth1
    ip netns exec A hping3 10.0.100.2 -2 --flood -d 60000 &
    ip netns del B

Splat looks like:
[   77.793450][    C3] ==================================================================
[   77.794702][    C3] BUG: KASAN: use-after-free in ip_tunnel_lookup+0xcc4/0xf30
[   77.795573][    C3] Read of size 4 at addr ffff888060bd9c84 by task hping3/2905
[   77.796398][    C3]
[   77.796664][    C3] CPU: 3 PID: 2905 Comm: hping3 Not tainted 5.8.0-rc1+ #616
[   77.797474][    C3] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[   77.798453][    C3] Call Trace:
[   77.798815][    C3]  <IRQ>
[   77.799142][    C3]  dump_stack+0x9d/0xdb
[   77.799605][    C3]  print_address_description.constprop.7+0x2cc/0x450
[   77.800365][    C3]  ? ip_tunnel_lookup+0xcc4/0xf30
[   77.800908][    C3]  ? ip_tunnel_lookup+0xcc4/0xf30
[   77.801517][    C3]  ? ip_tunnel_lookup+0xcc4/0xf30
[   77.802145][    C3]  kasan_report+0x154/0x190
[   77.802821][    C3]  ? ip_tunnel_lookup+0xcc4/0xf30
[   77.803503][    C3]  ip_tunnel_lookup+0xcc4/0xf30
[   77.804165][    C3]  __ipgre_rcv+0x1ab/0xaa0 [ip_gre]
[   77.804862][    C3]  ? rcu_read_lock_sched_held+0xc0/0xc0
[   77.805621][    C3]  gre_rcv+0x304/0x1910 [ip_gre]
[   77.806293][    C3]  ? lock_acquire+0x1a9/0x870
[   77.806925][    C3]  ? gre_rcv+0xfe/0x354 [gre]
[   77.807559][    C3]  ? erspan_xmit+0x2e60/0x2e60 [ip_gre]
[   77.808305][    C3]  ? rcu_read_lock_sched_held+0xc0/0xc0
[   77.809032][    C3]  ? rcu_read_lock_held+0x90/0xa0
[   77.809713][    C3]  gre_rcv+0x1b8/0x354 [gre]
[ ... ]

Suggested-by: Eric Dumazet <[email protected]>
Fixes: c544193 ("GRE: Refactor GRE tunneling code.")
Signed-off-by: Taehee Yoo <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
nathanchance pushed a commit that referenced this issue Jun 26, 2020
@TaeheeYoo @davem330
hsr: avoid to create proc file after unregister
de0083c 
When an interface is being deleted, "/proc/net/dev_snmp6/<interface name>"
is deleted.
The function for this is addrconf_ifdown() in the addrconf_notify() and
it is called by notification, which is NETDEV_UNREGISTER.
But, if NETDEV_CHANGEMTU is triggered after NETDEV_UNREGISTER,
this proc file will be created again.
This recreated proc file will be deleted by netdev_wati_allrefs().
Before netdev_wait_allrefs() is called, creating a new HSR interface
routine can be executed and It tries to create a proc file but it will
find an un-deleted proc file.
At this point, it warns about it.

To avoid this situation, it can use ->dellink() instead of
->ndo_uninit() to release resources because ->dellink() is called
before NETDEV_UNREGISTER.
So, a proc file will not be recreated.

Test commands
    ip link add dummy0 type dummy
    ip link add dummy1 type dummy
    ip link set dummy0 mtu 1300

    #SHELL1
    while :
    do
        ip link add hsr0 type hsr slave1 dummy0 slave2 dummy1
    done

    #SHELL2
    while :
    do
        ip link del hsr0
    done

Splat looks like:
[ 9888.980852][ T2752] proc_dir_entry 'dev_snmp6/hsr0' already registered
[ 9888.981797][    C2] WARNING: CPU: 2 PID: 2752 at fs/proc/generic.c:372 proc_register+0x2d5/0x430
[ 9888.981798][    C2] Modules linked in: hsr dummy veth openvswitch nsh nf_conncount nf_nat nf_conntrack nf_defrag_ipv6x
[ 9888.981814][    C2] CPU: 2 PID: 2752 Comm: ip Tainted: G        W         5.8.0-rc1+ #616
[ 9888.981815][    C2] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 9888.981816][    C2] RIP: 0010:proc_register+0x2d5/0x430
[ 9888.981818][    C2] Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 65 01 00 00 49 8b b5 e0 00 00 00 48 89 ea 40
[ 9888.981819][    C2] RSP: 0018:ffff8880628dedf0 EFLAGS: 00010286
[ 9888.981821][    C2] RAX: dffffc0000000008 RBX: ffff888028c69170 RCX: ffffffffaae09a62
[ 9888.981822][    C2] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88806c9f75ac
[ 9888.981823][    C2] RBP: ffff888028c693f4 R08: ffffed100d9401bd R09: ffffed100d9401bd
[ 9888.981824][    C2] R10: ffffffffaddf406f R11: 0000000000000001 R12: ffff888028c69308
[ 9888.981825][    C2] R13: ffff8880663584c8 R14: dffffc0000000000 R15: ffffed100518d27e
[ 9888.981827][    C2] FS:  00007f3876b3b0c0(0000) GS:ffff88806c800000(0000) knlGS:0000000000000000
[ 9888.981828][    C2] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9888.981829][    C2] CR2: 00007f387601a8c0 CR3: 000000004101a002 CR4: 00000000000606e0
[ 9888.981830][    C2] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 9888.981831][    C2] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 9888.981832][    C2] Call Trace:
[ 9888.981833][    C2]  ? snmp6_seq_show+0x180/0x180
[ 9888.981834][    C2]  proc_create_single_data+0x7c/0xa0
[ 9888.981835][    C2]  snmp6_register_dev+0xb0/0x130
[ 9888.981836][    C2]  ipv6_add_dev+0x4b7/0xf60
[ 9888.981837][    C2]  addrconf_notify+0x684/0x1ca0
[ 9888.981838][    C2]  ? __mutex_unlock_slowpath+0xd0/0x670
[ 9888.981839][    C2]  ? kasan_unpoison_shadow+0x30/0x40
[ 9888.981840][    C2]  ? wait_for_completion+0x250/0x250
[ 9888.981841][    C2]  ? inet6_ifinfo_notify+0x100/0x100
[ 9888.981842][    C2]  ? dropmon_net_event+0x227/0x410
[ 9888.981843][    C2]  ? notifier_call_chain+0x90/0x160
[ 9888.981844][    C2]  ? inet6_ifinfo_notify+0x100/0x100
[ 9888.981845][    C2]  notifier_call_chain+0x90/0x160
[ 9888.981846][    C2]  register_netdevice+0xbe5/0x1070
[ ... ]

Reported-by: [email protected]
Fixes: e0a4b99 ("hsr: use upper/lower device infrastructure")
Signed-off-by: Taehee Yoo <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@tpimh @nickdesaulniers @nathanchance