# git rev-parse -q --verify f8c29fc27feb230a3383204f22aa5474042f6ed8^{commit}
f8c29fc27feb230a3383204f22aa5474042f6ed8
already have revision, skipping fetch
# git checkout -q -f -B kisskb f8c29fc27feb230a3383204f22aa5474042f6ed8
# git clean -qxdf
# < git log -1
# commit f8c29fc27feb230a3383204f22aa5474042f6ed8
# Author: Michael Ellerman <mpe@ellerman.id.au>
# Date:   Mon Aug 19 22:24:01 2024 +1000
# 
#     powerpc/pseries: Fix dtl_access_lock to be a rw_semaphore
#     
#     The dtl_access_lock needs to be a rw_sempahore, a sleeping lock, because
#     the code calls kmalloc() while holding it, which can sleep:
#     
#       # echo 1 > /proc/powerpc/vcpudispatch_stats
#       BUG: sleeping function called from invalid context at include/linux/sched/mm.h:337
#       in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 199, name: sh
#       preempt_count: 1, expected: 0
#       3 locks held by sh/199:
#        #0: c00000000a0743f8 (sb_writers#3){.+.+}-{0:0}, at: vfs_write+0x324/0x438
#        #1: c0000000028c7058 (dtl_enable_mutex){+.+.}-{3:3}, at: vcpudispatch_stats_write+0xd4/0x5f4
#        #2: c0000000028c70b8 (dtl_access_lock){+.+.}-{2:2}, at: vcpudispatch_stats_write+0x220/0x5f4
#       CPU: 0 PID: 199 Comm: sh Not tainted 6.10.0-rc4 #152
#       Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries
#       Call Trace:
#         dump_stack_lvl+0x130/0x148 (unreliable)
#         __might_resched+0x174/0x410
#         kmem_cache_alloc_noprof+0x340/0x3d0
#         alloc_dtl_buffers+0x124/0x1ac
#         vcpudispatch_stats_write+0x2a8/0x5f4
#         proc_reg_write+0xf4/0x150
#         vfs_write+0xfc/0x438
#         ksys_write+0x88/0x148
#         system_call_exception+0x1c4/0x5a0
#         system_call_common+0xf4/0x258
#     
#     Fixes: 06220d78f24a ("powerpc/pseries: Introduce rwlock to gatekeep DTLB usage")
#     Tested-by: Kajol Jain <kjain@linux.ibm.com>
#     Reviewed-by: Nysal Jan K.A <nysal@linux.ibm.com>
#     Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://msgid.link/20240819122401.513203-1-mpe@ellerman.id.au
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 f8c29fc27feb230a3383204f22aa5474042f6ed8
# make -s -j 40 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64e_defconfig+KEXEC_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  ppc64e_defconfig
# Added to kconfig CONFIG_KEXEC=y
# < make -s -j 40 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64e_defconfig+KEXEC_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 40 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64e_defconfig+KEXEC_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
.config:3226:warning: override: reassigning to symbol KEXEC
# make -s -j 40 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64e_defconfig+KEXEC_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_ppc64e_defconfig+KEXEC_powerpc-gcc5
# Build took: 0:01:12.467597