# git rev-parse -q --verify 8d48562a2729742f767b0fdd994d6b2a56a49c63^{commit}
8d48562a2729742f767b0fdd994d6b2a56a49c63
already have revision, skipping fetch
# git checkout -q -f -B kisskb 8d48562a2729742f767b0fdd994d6b2a56a49c63
# git clean -qxdf
# < git log -1
# commit 8d48562a2729742f767b0fdd994d6b2a56a49c63
# Author: Michael Ellerman <mpe@ellerman.id.au>
# Date:   Mon Aug 15 16:55:23 2022 +1000
# 
#     powerpc/pci: Fix get_phb_number() locking
#     
#     The recent change to get_phb_number() causes a DEBUG_ATOMIC_SLEEP
#     warning on some systems:
#     
#       BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
#       in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper
#       preempt_count: 1, expected: 0
#       RCU nest depth: 0, expected: 0
#       1 lock held by swapper/1:
#        #0: c157efb0 (hose_spinlock){+.+.}-{2:2}, at: pcibios_alloc_controller+0x64/0x220
#       Preemption disabled at:
#       [<00000000>] 0x0
#       CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0-yocto-standard+ #1
#       Call Trace:
#       [d101dc90] [c073b264] dump_stack_lvl+0x50/0x8c (unreliable)
#       [d101dcb0] [c0093b70] __might_resched+0x258/0x2a8
#       [d101dcd0] [c0d3e634] __mutex_lock+0x6c/0x6ec
#       [d101dd50] [c0a84174] of_alias_get_id+0x50/0xf4
#       [d101dd80] [c002ec78] pcibios_alloc_controller+0x1b8/0x220
#       [d101ddd0] [c140c9dc] pmac_pci_init+0x198/0x784
#       [d101de50] [c140852c] discover_phbs+0x30/0x4c
#       [d101de60] [c0007fd4] do_one_initcall+0x94/0x344
#       [d101ded0] [c1403b40] kernel_init_freeable+0x1a8/0x22c
#       [d101df10] [c00086e0] kernel_init+0x34/0x160
#       [d101df30] [c001b334] ret_from_kernel_thread+0x5c/0x64
#     
#     This is because pcibios_alloc_controller() holds hose_spinlock but
#     of_alias_get_id() takes of_mutex which can sleep.
#     
#     The hose_spinlock protects the phb_bitmap, and also the hose_list, but
#     it doesn't need to be held while get_phb_number() calls the OF routines,
#     because those are only looking up information in the device tree.
#     
#     So fix it by having get_phb_number() take the hose_spinlock itself, only
#     where required, and then dropping the lock before returning.
#     pcibios_alloc_controller() then needs to take the lock again before the
#     list_add() but that's safe, the order of the list is not important.
#     
#     Fixes: 0fe1e96fef0a ("powerpc/pci: Prefer PCI domain assignment via DT 'linux,pci-domain' and alias")
#     Reported-by: Guenter Roeck <linux@roeck-us.net>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20220815065550.1303620-1-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 8d48562a2729742f767b0fdd994d6b2a56a49c63
# < make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mvme5100_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  mvme5100_defconfig
# < make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mvme5100_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mvme5100_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
# make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mvme5100_defconfig_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_mvme5100_defconfig_powerpc-gcc5
# Build took: 0:01:11.121819