# git rev-parse -q --verify 1344a232016dbb0492be81f8517c4bf8fc1c6610^{commit} # git fetch -q -n -f git://gitlab.ozlabs.ibm.com/linuxppc/linux.git fixes-test warning: The last gc run reported the following. Please correct the root cause and remove .git/gc.log. Automatic cleanup will not be performed until the file is removed. warning: There are too many unreachable loose objects; run 'git prune' to remove them. # git rev-parse -q --verify 1344a232016dbb0492be81f8517c4bf8fc1c6610^{commit} 1344a232016dbb0492be81f8517c4bf8fc1c6610 # git checkout -q -f -B kisskb 1344a232016dbb0492be81f8517c4bf8fc1c6610 # git clean -qxdf # < git log -1 # commit 1344a232016dbb0492be81f8517c4bf8fc1c6610 # Author: Michael Ellerman # Date: Wed Nov 4 22:17:42 2020 +1100 # # powerpc: Use asm_goto_volatile for put_user() # # Andreas reported that commit ee0a49a6870e ("powerpc/uaccess: Switch # __put_user_size_allowed() to __put_user_asm_goto()") broke # CLONE_CHILD_SETTID. # # Further inspection showed that the put_user() in schedule_tail() was # missing entirely, the store not emitted by the compiler. # # <.schedule_tail>: # mflr r0 # std r0,16(r1) # stdu r1,-112(r1) # bl <.finish_task_switch> # ld r9,2496(r3) # cmpdi cr7,r9,0 # bne cr7,<.schedule_tail+0x60> # ld r3,392(r13) # ld r9,1392(r3) # cmpdi cr7,r9,0 # beq cr7,<.schedule_tail+0x3c> # li r4,0 # li r5,0 # bl <.__task_pid_nr_ns> # nop # bl <.calculate_sigpending> # nop # addi r1,r1,112 # ld r0,16(r1) # mtlr r0 # blr # nop # nop # nop # bl <.__balance_callback> # b <.schedule_tail+0x1c> # # Notice there are no stores other than to the stack. There should be a # stw in there for the store to current->set_child_tid. # # This is only seen with GCC 4.9 era compilers (tested with 4.9.3 and # 4.9.4), and only when CONFIG_PPC_KUAP is disabled. # # When CONFIG_PPC_KUAP=y, the inline asm that's part of the isync() # and mtspr() inlined via allow_user_access() seems to be enough to # avoid the bug. # # We already have a macro to work around this (or a similar bug), called # asm_volatile_goto which includes an empty asm block to tickle the # compiler into generating the right code. So use that. # # With this applied the code generation looks more like it will work: # # <.schedule_tail>: # mflr r0 # std r31,-8(r1) # std r0,16(r1) # stdu r1,-144(r1) # std r3,112(r1) # bl <._mcount> # nop # ld r3,112(r1) # bl <.finish_task_switch> # ld r9,2624(r3) # cmpdi cr7,r9,0 # bne cr7,<.schedule_tail+0xa0> # ld r3,2408(r13) # ld r31,1856(r3) # cmpdi cr7,r31,0 # beq cr7,<.schedule_tail+0x80> # li r4,0 # li r5,0 # bl <.__task_pid_nr_ns> # nop # li r9,-1 # clrldi r9,r9,12 # cmpld cr7,r31,r9 # bgt cr7,<.schedule_tail+0x80> # lis r9,16 # rldicr r9,r9,32,31 # subf r9,r31,r9 # cmpldi cr7,r9,3 # ble cr7,<.schedule_tail+0x80> # li r9,0 # stw r3,0(r31) <-- stw # nop # bl <.calculate_sigpending> # nop # addi r1,r1,144 # ld r0,16(r1) # ld r31,-8(r1) # mtlr r0 # blr # nop # bl <.__balance_callback> # b <.schedule_tail+0x30> # # Fixes: ee0a49a6870e ("powerpc/uaccess: Switch __put_user_size_allowed() to __put_user_asm_goto()") # Reported-by: Andreas Schwab # Tested-by: Andreas Schwab # Suggested-by: Christophe Leroy # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20201104111742.672142-1-mpe@ellerman.id.au # < /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 1344a232016dbb0492be81f8517c4bf8fc1c6610 # < make -s -j 8 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 8 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 8 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 8 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: 0:03:33.661212