# git rev-parse -q --verify a3ac7917b73070010c05b4485b8582a6c9cd69b6^{commit}
a3ac7917b73070010c05b4485b8582a6c9cd69b6
already have revision, skipping fetch
# git checkout -q -f -B kisskb a3ac7917b73070010c05b4485b8582a6c9cd69b6
# git clean -qxdf
# < git log -1
# commit a3ac7917b73070010c05b4485b8582a6c9cd69b6
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Mon Mar 25 14:49:00 2019 -0700
# 
#     Revert "parport: daisy: use new parport device model"
#     
#     This reverts commit 1aec4211204d9463d1fd209eb50453de16254599.
#     
#     Steven Rostedt reports that it causes a hang at bootup and bisected it
#     to this commit.
#     
#     The troigger is apparently a module alias for "parport_lowlevel" that
#     points to "parport_pc", which causes a hang with
#     
#         modprobe -q -- parport_lowlevel
#     
#     blocking forever with a backtrace like this:
#     
#         wait_for_completion_killable+0x1c/0x28
#         call_usermodehelper_exec+0xa7/0x108
#         __request_module+0x351/0x3d8
#         get_lowlevel_driver+0x28/0x41 [parport]
#         __parport_register_driver+0x39/0x1f4 [parport]
#         daisy_drv_init+0x31/0x4f [parport]
#         parport_bus_init+0x5d/0x7b [parport]
#         parport_default_proc_register+0x26/0x1000 [parport]
#         do_one_initcall+0xc2/0x1e0
#         do_init_module+0x50/0x1d4
#         load_module+0x1c2e/0x21b3
#         sys_init_module+0xef/0x117
#     
#     Supid says:
#      "Due to the new device model daisy driver will now try to find the
#       parallel ports while trying to register its driver so that it can bind
#       with them. Now, since daisy driver is loaded while parport bus is
#       initialising the list of parport is still empty and it tries to load
#       the lowlevel driver, which has an alias set to parport_pc, now causes
#       a deadlock"
#     
#     But I don't think the daisy driver should be loaded by the parport
#     initialization in the first place, so let's revert the whole change.
#     
#     If the daisy driver can just initialize separately on its own (like a
#     driver should), instead of hooking into the parport init sequence
#     directly, this issue probably would go away.
#     
#     Reported-and-bisected-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
#     Reported-by: Michal Kubecek <mkubecek@suse.cz>
#     Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
#     Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/s390x-linux/bin/s390x-linux-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/s390x-linux/bin/s390x-linux-ld --version
# < git log --format=%s --max-count=1 a3ac7917b73070010c05b4485b8582a6c9cd69b6
# < make -s -j 8 ARCH=s390 O=/kisskb/build/linus_s390-allnoconfig_s390x CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/s390x-linux/bin/s390x-linux-  allnoconfig
# make -s -j 8 ARCH=s390 O=/kisskb/build/linus_s390-allnoconfig_s390x CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/s390x-linux/bin/s390x-linux-  
<stdin>:1478:2: warning: #warning syscall pidfd_send_signal not implemented [-Wcpp]
<stdin>:1481:2: warning: #warning syscall io_uring_setup not implemented [-Wcpp]
<stdin>:1484:2: warning: #warning syscall io_uring_enter not implemented [-Wcpp]
<stdin>:1487:2: warning: #warning syscall io_uring_register not implemented [-Wcpp]
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:187:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/arch/s390/mm/pgtable.c:413:15: warning: 'pmd_alloc_map' defined but not used [-Wunused-function]
/kisskb/src/arch/s390/kernel/machine_kexec.c:145:22: warning: 'do_start_kdump' defined but not used [-Wunused-function]
Completed OK
# rm -rf /kisskb/build/linus_s390-allnoconfig_s390x
# Build took: 0:00:20.712584