# git rev-parse -q --verify 99f070b62322a4b8c1252952735806d09eb44b68^{commit} # git fetch -q -n -f git://gitlab.ozlabs.ibm.com/linuxppc/linux.git fixes-test # git rev-parse -q --verify 99f070b62322a4b8c1252952735806d09eb44b68^{commit} 99f070b62322a4b8c1252952735806d09eb44b68 # git checkout -q -f -B kisskb 99f070b62322a4b8c1252952735806d09eb44b68 # git clean -qxdf # < git log -1 # commit 99f070b62322a4b8c1252952735806d09eb44b68 # Author: Qian Cai # Date: Wed Oct 28 14:23:34 2020 -0400 # # powerpc/smp: Call rcu_cpu_starting() earlier # # The call to rcu_cpu_starting() in start_secondary() is not early # enough in the CPU-hotplug onlining process, which results in lockdep # splats as follows (with CONFIG_PROVE_RCU_LIST=y): # # WARNING: suspicious RCU usage # ----------------------------- # kernel/locking/lockdep.c:3497 RCU-list traversed in non-reader section!! # # other info that might help us debug this: # # RCU used illegally from offline CPU! # rcu_scheduler_active = 1, debug_locks = 1 # no locks held by swapper/1/0. # # Call Trace: # dump_stack+0xec/0x144 (unreliable) # lockdep_rcu_suspicious+0x128/0x14c # __lock_acquire+0x1060/0x1c60 # lock_acquire+0x140/0x5f0 # _raw_spin_lock_irqsave+0x64/0xb0 # clockevents_register_device+0x74/0x270 # register_decrementer_clockevent+0x94/0x110 # start_secondary+0x134/0x800 # start_secondary_prolog+0x10/0x14 # # This is avoided by adding a call to rcu_cpu_starting() near the # beginning of the start_secondary() function. Note that the # raw_smp_processor_id() is required in order to avoid calling into # lockdep before RCU has declared the CPU to be watched for readers. # # It's safe to call rcu_cpu_starting() in the arch code as well as later # in generic code, as explained by Paul: # # It uses a per-CPU variable so that RCU pays attention only to the # first call to rcu_cpu_starting() if there is more than one of them. # This is even intentional, due to there being a generic # arch-independent call to rcu_cpu_starting() in # notify_cpu_starting(). # # So multiple calls to rcu_cpu_starting() are fine by design. # # Fixes: 4d004099a668 ("lockdep: Fix lockdep recursion") # Signed-off-by: Qian Cai # Acked-by: Paul E. McKenney # [mpe: Add Fixes tag, reword slightly & expand change log] # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20201028182334.13466-1-cai@redhat.com # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux-ld --version # < git log --format=%s --max-count=1 99f070b62322a4b8c1252952735806d09eb44b68 # < make -s -j 24 ARCH=m68k O=/kisskb/build/powerpc-fixes_m68k-defconfig_m68k-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux- defconfig # < make -s -j 24 ARCH=m68k O=/kisskb/build/powerpc-fixes_m68k-defconfig_m68k-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux- help # make -s -j 24 ARCH=m68k O=/kisskb/build/powerpc-fixes_m68k-defconfig_m68k-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux- olddefconfig # make -s -j 24 ARCH=m68k O=/kisskb/build/powerpc-fixes_m68k-defconfig_m68k-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux- /kisskb/src/arch/m68k/mvme147/config.c: In function 'mvme147_hwclk': /kisskb/src/arch/m68k/mvme147/config.c:174:2: warning: #warning check me! [-Wcpp] #warning check me! ^~~~~~~ /kisskb/src/arch/m68k/mvme16x/config.c: In function 'mvme16x_hwclk': /kisskb/src/arch/m68k/mvme16x/config.c:439:2: warning: #warning check me! [-Wcpp] #warning check me! ^~~~~~~ In file included from /kisskb/src/kernel/rcu/update.c:578: /kisskb/src/kernel/rcu/tasks.h:710:13: warning: 'show_rcu_tasks_rude_gp_kthread' defined but not used [-Wunused-function] static void show_rcu_tasks_rude_gp_kthread(void) {} ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /kisskb/src/drivers/net/ethernet/8390/xsurf100.c:48: /kisskb/src/drivers/net/ethernet/8390/lib8390.c:995:27: warning: '____alloc_ei_netdev' defined but not used [-Wunused-function] static struct net_device *____alloc_ei_netdev(int size) ^~~~~~~~~~~~~~~~~~~ /kisskb/src/drivers/net/ethernet/8390/lib8390.c:957:13: warning: '__ei_set_multicast_list' defined but not used [-Wunused-function] static void __ei_set_multicast_list(struct net_device *dev) ^~~~~~~~~~~~~~~~~~~~~~~ /kisskb/src/drivers/net/ethernet/8390/lib8390.c:857:33: warning: '__ei_get_stats' defined but not used [-Wunused-function] static struct net_device_stats *__ei_get_stats(struct net_device *dev) ^~~~~~~~~~~~~~ /kisskb/src/drivers/net/ethernet/8390/lib8390.c:512:13: warning: '__ei_poll' defined but not used [-Wunused-function] static void __ei_poll(struct net_device *dev) ^~~~~~~~~ /kisskb/src/drivers/net/ethernet/8390/lib8390.c:303:20: warning: '__ei_start_xmit' defined but not used [-Wunused-function] static netdev_tx_t __ei_start_xmit(struct sk_buff *skb, ^~~~~~~~~~~~~~~ /kisskb/src/drivers/net/ethernet/8390/lib8390.c:257:13: warning: '__ei_tx_timeout' defined but not used [-Wunused-function] static void __ei_tx_timeout(struct net_device *dev, unsigned int txqueue) ^~~~~~~~~~~~~~~ /kisskb/src/drivers/net/ethernet/8390/lib8390.c:233:12: warning: '__ei_close' defined but not used [-Wunused-function] static int __ei_close(struct net_device *dev) ^~~~~~~~~~ /kisskb/src/drivers/net/ethernet/8390/lib8390.c:204:12: warning: '__ei_open' defined but not used [-Wunused-function] static int __ei_open(struct net_device *dev) ^~~~~~~~~ In file included from /kisskb/src/arch/m68k/include/asm/atomic.h:7, from /kisskb/src/include/linux/atomic.h:7, from /kisskb/src/include/linux/cpumask.h:13, from /kisskb/src/include/linux/smp.h:13, from /kisskb/src/include/linux/lockdep.h:14, from /kisskb/src/include/linux/spinlock.h:59, from /kisskb/src/include/linux/wait.h:9, from /kisskb/src/include/linux/wait_bit.h:8, from /kisskb/src/include/linux/fs.h:6, from /kisskb/src/fs/ocfs2/file.c:13: /kisskb/src/fs/ocfs2/file.c: In function 'ocfs2_file_write_iter': /kisskb/src/arch/m68k/include/asm/cmpxchg.h:79:22: warning: value computed is not used [-Wunused-value] #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)))) ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /kisskb/src/fs/ocfs2/file.c:2419:3: note: in expansion of macro 'xchg' xchg(&iocb->ki_complete, saved_ki_complete); ^~~~ Completed OK # rm -rf /kisskb/build/powerpc-fixes_m68k-defconfig_m68k-gcc8 # Build took: 0:02:41.086906