glibc 2.28-0ubuntu1 ADT test failure with linux 4.19.0-5.6

[Seth Forshee]

Testing failed on:
    amd64: https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-disco-canonical-kernel-team-bootstrap/disco/amd64/g/glibc/20181119_075302_9b2e2@/log.gz
    i386: https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-disco-canonical-kernel-team-bootstrap/disco/i386/g/glibc/20181119_064219_9b2e2@/log.gz

[H.J. (h.j.-redhat-bugs)]

Under 4.19.2-300 kernel, i686 glibc tests failed with:

FAIL: debug/tst-backtrace5
FAIL: debug/tst-backtrace6
FAIL: nptl/tst-cancel24
FAIL: nptl/tst-cancel24-static
FAIL: nptl/tst-cancelx16
FAIL: nptl/tst-cancelx18
FAIL: nptl/tst-cancelx20
FAIL: nptl/tst-cancelx21
FAIL: nptl/tst-cancelx4
FAIL: nptl/tst-cancelx5
FAIL: nptl/tst-cleanupx4
FAIL: nptl/tst-oncex3
FAIL: nptl/tst-oncex4

[hjl@gnu-skx-1 build-i686-linux]$ debug/tst-backtrace5 --direct
Obtained backtrace with 3 functions
Failure on line 53
[hjl@gnu-skx-1 build-i686-linux]$

Under 4.18.18-300 kernel, I got

Obtained backtrace with 7 functions
Function 0: debug/tst-backtrace5(handle_signal+0x1b) [0x804a42b]
Function 1: linux-gate.so.1(__kernel_sigreturn+0) [0xf7f7b0b0]
Function 2: linux-gate.so.1(__kernel_vsyscall+0x9) [0xf7f7b099]
Function 3: /export/build/gnu/tools-build/glibc-32bit/build-i686-linux/libc.so.6(__read+0x2d) [0xf7e99c8d]
Function 4: debug/tst-backtrace5(fn+0x105) [0x804a745]
Function 5: debug/tst-backtrace5(fn+0xd4) [0x804a714]
Function 6: debug/tst-backtrace5(fn+0xd4) [0x804a714]

[hjl.tools (hjl.tools-linux-kernel-bugs)]

Created attachment 279555
A testcase

commit 379d98ddf41344273d9718556f761420f4dc80b3
Author: Alistair Strachan <email address hidden>
Date: Fri Aug 3 10:39:31 2018 -0700

    x86: vdso: Use $LD instead of $CC to link

    The vdso{32,64}.so can fail to link with CC=clang when clang tries to find
    a suitable GCC toolchain to link these libraries with.

    /usr/bin/ld: arch/x86/entry/vdso/vclock_gettime.o:
      access beyond end of merged section (782)

breaks i386 vDSO with incorrect unwind info. The testcase here should
report:

[hjl@gnu-hsw-1 tmp]$ gcc -g -O2 -funwind-tables -m32 foo.c
[hjl@gnu-hsw-1 tmp]$ ./a.out
Obtained backtrace with 7 functions
Function 0: ./a.out() [0x8049272]
Function 1: linux-gate.so.1(__kernel_sigreturn+0) [0xf7f990b0]
Function 2: linux-gate.so.1(__kernel_vsyscall+0x9) [0xf7f99099]
Function 3: /lib/libc.so.6(__read+0x2b) [0xf7ea72ab]
Function 4: ./a.out() [0x80493a9]
Function 5: ./a.out() [0x80493f3]
Function 6: ./a.out() [0x80493f3]
[hjl@gnu-hsw-1 tmp]$

But kernel 4.19 got

[hjl@gnu-cfl-1 tmp]$ ./a.out
Obtained backtrace with 4 functions
Failure on line 67
[hjl@gnu-cfl-1 tmp]$

Revert the commit fixes i386 vDSO.

[H.J. (h.j.-redhat-bugs)]

This is caused by

commit 379d98ddf41344273d9718556f761420f4dc80b3
Author: Alistair Strachan <email address hidden>
Date: Fri Aug 3 10:39:31 2018 -0700

    x86: vdso: Use $LD instead of $CC to link

    The vdso{32,64}.so can fail to link with CC=clang when clang tries to find
    a suitable GCC toolchain to link these libraries with.

    /usr/bin/ld: arch/x86/entry/vdso/vclock_gettime.o:
      access beyond end of merged section (782)

[Seth Forshee (sforshee)]

Looks to be a regression in the vdso caused by 379d98ddf41344273d9718556f761420f4dc80b3 "x86: vdso: Use $LD instead of $CC to link" in Linux 4.19.

[Seth Forshee (sforshee)]

Applied a revert of 379d98ddf41344273d9718556f761420f4dc80b3 to fix this until a fix is available upstream.

[fweimer (fweimer-linux-kernel-bugs)]

The GNU_EH_FRAME segment is actually empty in our builds. This breaks unwinding across signal handlers on i386 because the libgcc unwinder does not recognize i386 __kernel_sigreturn as a signal handler frame anymore.

[hongjiu.lu (hongjiu.lu-redhat-bugs)]

*** This bug has been marked as a duplicate of bug 1659295 ***

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.19.0-12.13

---------------
linux (4.19.0-12.13) disco; urgency=medium

  * linux: 4.19.0-12.13 -proposed tracker (LP: #1813664)

  * kernel oops in bcache module (LP: #1793901)
    - SAUCE: bcache: never writeback a discard operation

  * Disco update: 4.19.18 upstream stable release (LP: #1813611)
    - ipv6: Consider sk_bound_dev_if when binding a socket to a v4 mapped address
    - mlxsw: spectrum: Disable lag port TX before removing it
    - mlxsw: spectrum_switchdev: Set PVID correctly during VLAN deletion
    - net: dsa: mv88x6xxx: mv88e6390 errata
    - net, skbuff: do not prefer skb allocation fails early
    - qmi_wwan: add MTU default to qmap network interface
    - ipv6: Take rcu_read_lock in __inet6_bind for mapped addresses
    - net: clear skb->tstamp in bridge forwarding path
    - netfilter: ipset: Allow matching on destination MAC address for mac and
      ipmac sets
    - gpio: pl061: Move irq_chip definition inside struct pl061
    - drm/amd/display: Guard against null stream_state in set_crc_source
    - drm/amdkfd: fix interrupt spin lock
    - ixgbe: allow IPsec Tx offload in VEPA mode
    - platform/x86: asus-wmi: Tell the EC the OS will handle the display off
      hotkey
    - e1000e: allow non-monotonic SYSTIM readings
    - usb: typec: tcpm: Do not disconnect link for self powered devices
    - selftests/bpf: enable (uncomment) all tests in test_libbpf.sh
    - of: overlay: add missing of_node_put() after add new node to changeset
    - writeback: don't decrement wb->refcnt if !wb->bdi
    - serial: set suppress_bind_attrs flag only if builtin
    - bpf: Allow narrow loads with offset > 0
    - ALSA: oxfw: add support for APOGEE duet FireWire
    - x86/mce: Fix -Wmissing-prototypes warnings
    - MIPS: SiByte: Enable swiotlb for SWARM, LittleSur and BigSur
    - crypto: ecc - regularize scalar for scalar multiplication
    - arm64: perf: set suppress_bind_attrs flag to true
    - drm/atomic-helper: Complete fake_commit->flip_done potentially earlier
    - clk: meson: meson8b: fix incorrect divider mapping in cpu_scale_table
    - samples: bpf: fix: error handling regarding kprobe_events
    - usb: gadget: udc: renesas_usb3: add a safety connection way for
      forced_b_device
    - fpga: altera-cvp: fix probing for multiple FPGAs on the bus
    - selinux: always allow mounting submounts
    - ASoC: pcm3168a: Don't disable pcm3168a when CONFIG_PM defined
    - scsi: qedi: Check for session online before getting iSCSI TLV data.
    - drm/amdgpu: Reorder uvd ring init before uvd resume
    - rxe: IB_WR_REG_MR does not capture MR's iova field
    - efi/libstub: Disable some warnings for x86{,_64}
    - jffs2: Fix use of uninitialized delayed_work, lockdep breakage
    - clk: imx: make mux parent strings const
    - pstore/ram: Do not treat empty buffers as valid
    - media: uvcvideo: Refactor teardown of uvc on USB disconnect
    - powerpc/xmon: Fix invocation inside lock region
    - powerpc/pseries/cpuidle: Fix preempt warning
    - media: firewire: Fix app_info parameter type in avc_ca{,_app}_info
    - ASoC: use dma_ops of parent device for acp_audio_dma
    - media: ve...