# git rev-parse -q --verify ed20662c89f2490da494826fe6c0f58f46524385^{commit} ed20662c89f2490da494826fe6c0f58f46524385 already have revision, skipping fetch # git checkout -q -f -B kisskb ed20662c89f2490da494826fe6c0f58f46524385 # git clean -qxdf # < git log -1 # commit ed20662c89f2490da494826fe6c0f58f46524385 # Author: Michael Ellerman # Date: Thu Feb 14 15:00:36 2019 +1100 # # powerpc/64s: Fix possible corruption on big endian due to pgd/pud_present() # # In v4.20 we changed our pgd/pud_present() to check for _PAGE_PRESENT # rather than just checking that the value is non-zero, e.g.: # # static inline int pgd_present(pgd_t pgd) # { # - return !pgd_none(pgd); # + return (pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT)); # } # # Unfortunately this is broken on big endian, as the result of the # bitwise && is truncated to int, which is always zero because # _PAGE_PRESENT is 0x8000000000000000ul. This means pgd_present() and # pud_present() are always false at compile time, and the compiler # elides the subsequent code. # # Remarkably with that bug present we are still able to boot and run # with few noticeable effects. However under some work loads we are able # to trigger a warning in the ext4 code: # # WARNING: CPU: 11 PID: 29593 at fs/ext4/inode.c:3927 .ext4_set_page_dirty+0x70/0xb0 # CPU: 11 PID: 29593 Comm: debugedit Not tainted 4.20.0-rc1 #1 # ... # NIP .ext4_set_page_dirty+0x70/0xb0 # LR .set_page_dirty+0xa0/0x150 # Call Trace: # .set_page_dirty+0xa0/0x150 # .unmap_page_range+0xbf0/0xe10 # .unmap_vmas+0x84/0x130 # .unmap_region+0xe8/0x190 # .__do_munmap+0x2f0/0x510 # .__vm_munmap+0x80/0x110 # .__se_sys_munmap+0x14/0x30 # system_call+0x5c/0x70 # # The fix is simple, we need to convert the result of the bitwise && to # an int before returning it. # # Thanks to Erhard, Jan Kara and Aneesh for help with debugging. # # Fixes: da7ad366b497 ("powerpc/mm/book3s: Update pmd_present to look at _PAGE_PRESENT bit") # Cc: stable@vger.kernel.org # v4.20+ # Reported-by: Erhard F. # Reviewed-by: Aneesh Kumar K.V # Signed-off-by: Michael Ellerman # < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version # < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-ld --version # < git log --format=%s --max-count=1 ed20662c89f2490da494826fe6c0f58f46524385 # < make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_powerpc-randconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- randconfig KCONFIG_SEED=0xCCEAC32C # Added to kconfig CONFIG_STANDALONE=y # Added to kconfig CONFIG_BUILD_DOCSRC=n # Added to kconfig CONFIG_MODULE_SIG=n # Added to kconfig CONFIG_CPU_BIG_ENDIAN=y # Added to kconfig CONFIG_PPC64=y # Added to kconfig CONFIG_PPC_DISABLE_WERROR=y # Added to kconfig CONFIG_SECTION_MISMATCH_WARN_ONLY=y # Added to kconfig CONFIG_PREVENT_FIRMWARE_BUILD=y # Added to kconfig CONFIG_CC_STACKPROTECTOR_STRONG=n # Added to kconfig CONFIG_GCC_PLUGINS=n # Added to kconfig CONFIG_LD_HEAD_STUB_CATCH=y # Added to kconfig # yes \n | make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_powerpc-randconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- oldconfig yes: standard output: Broken pipe # make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_powerpc-randconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- /kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl': /kisskb/src/kernel/printk/printk.c:186:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/kernel/printk/printk.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/ipc/shm.c: In function 'ksys_shmdt': /kisskb/src/ipc/shm.c:1686:59: warning: 'file' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/ipc/shm.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/fs/afs/dir.c: In function 'afs_dir_set_page_dirty': /kisskb/src/fs/afs/dir.c:52:1: warning: no return statement in function returning non-void [-Wreturn-type] /kisskb/src/drivers/char/tpm/tpm-sysfs.c: In function 'pubek_show': /kisskb/src/drivers/char/tpm/tpm-sysfs.c:56:5: warning: 'tpm_buf.data' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/char/tpm/tpm-sysfs.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/arch/powerpc/kernel/exceptions-64e.S: Assembler messages: /kisskb/src/arch/powerpc/kernel/exceptions-64e.S:587: Error: Unrecognized opcode: `mc_btb_flush' make[3]: *** [/kisskb/src/scripts/Makefile.build:367: arch/powerpc/kernel/exceptions-64e.o] Error 1 make[3]: *** Waiting for unfinished jobs.... /kisskb/src/fs/afs/dir.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] make[2]: *** [/kisskb/src/scripts/Makefile.build:492: arch/powerpc/kernel] Error 2 make[2]: *** Waiting for unfinished jobs.... /kisskb/src/fs/afs/dynroot.c: In function 'afs_lookup_atcell': /kisskb/src/fs/afs/dynroot.c:126:6: warning: 'len' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/afs/dynroot.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/drivers/hwspinlock/hwspinlock_core.c: In function 'of_hwspin_lock_get_id': /kisskb/src/drivers/hwspinlock/hwspinlock_core.c:328:6: warning: 'id' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/hwspinlock/hwspinlock_core.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/lib/mpi/mpicoder.c: In function 'mpi_read_raw_from_sgl': /kisskb/src/lib/mpi/mpicoder.c:352:8: warning: 'buff' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/lib/mpi/mpicoder.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] make[1]: *** [/kisskb/src/Makefile:1042: arch/powerpc] Error 2 make[1]: *** Waiting for unfinished jobs.... /kisskb/src/drivers/i2c/i2c-core-base.c: In function 'i2c_generic_scl_recovery': /kisskb/src/drivers/i2c/i2c-core-base.c:235:5: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/i2c/i2c-core-base.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/mm/ksm.c: In function 'stable_node_dup': /kisskb/src/mm/ksm.c:1393:15: warning: 'found_rmap_hlist_len' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/mm/ksm.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/fs/udf/unicode.c: In function 'udf_name_conv_char': /kisskb/src/fs/udf/unicode.c:132:8: warning: 'c' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/udf/unicode.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/lib/rhashtable.c: In function 'rhashtable_rehash_one': /kisskb/src/lib/rhashtable.c:264:2: warning: 'next' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/core/gen_stats.c: In function '__gnet_stats_copy_basic': /kisskb/src/net/core/gen_stats.c:161:19: warning: 'seq' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/core/gen_stats.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/lib/rhashtable.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/net/ipv6/ip6_output.c: In function '__ip6_append_data.isra.36': /kisskb/src/include/linux/skbuff.h:1338:6: warning: 'extra_uref' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/ipv6/ip6_output.c:1270:14: note: 'extra_uref' was declared here /kisskb/src/drivers/input/mouse/cyapa.c: In function 'cyapa_irq': /kisskb/src/drivers/input/mouse/cyapa.c:717:27: warning: 'error' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/input/mouse/cyapa.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/drivers/input/mouse/cyapa_gen3.c: In function 'cyapa_gen3_set_power_mode': /kisskb/src/drivers/input/mouse/cyapa_gen3.c:927:5: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/input/mouse/cyapa_gen3.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/net/ipv6/ip6_output.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/net/core/dev.c: In function 'validate_xmit_skb_list': /kisskb/src/net/core/dev.c:3405:15: warning: 'tail' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/video/backlight/adp8870_bl.c: In function 'adp8870_bl_ambient_light_zone_show': /kisskb/src/drivers/video/backlight/adp8870_bl.c:785:32: warning: 'reg_val' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/video/backlight/adp8870_bl.c: In function 'adp8870_show': /kisskb/src/drivers/video/backlight/adp8870_bl.c:564:16: warning: 'reg_val' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/video/backlight/adp8870_bl.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/net/ipv4/ip_output.c: In function '__ip_append_data.isra.42': /kisskb/src/include/linux/skbuff.h:1338:6: warning: 'extra_uref' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/ipv4/ip_output.c:885:14: note: 'extra_uref' was declared here /kisskb/src/net/ipv4/ip_output.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/net/core/dev.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/net/ncsi/ncsi-manage.c: In function 'set_one_vid': /kisskb/src/net/ncsi/ncsi-manage.c:676:19: warning: 'vid' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/ncsi/ncsi-manage.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/drivers/video/backlight/adp8860_bl.c: In function 'adp8860_bl_ambient_light_zone_show': /kisskb/src/drivers/video/backlight/adp8860_bl.c:601:32: warning: 'reg_val' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/video/backlight/adp8860_bl.c: In function 'adp8860_bl_ambient_light_level_show': /kisskb/src/drivers/video/backlight/adp8860_bl.c:579:10: warning: 'reg_val' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/video/backlight/adp8860_bl.c:579:10: warning: 'ret_val' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/video/backlight/adp8860_bl.c: In function 'adp8860_show': /kisskb/src/drivers/video/backlight/adp8860_bl.c:443:16: warning: 'reg_val' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/video/backlight/adp8860_bl.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/net/tipc/socket.c: In function 'tipc_recvmsg': /kisskb/src/net/tipc/socket.c:1734:27: warning: 'copy' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/tipc/socket.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/drivers/gpu/drm/drm_atomic.c: In function 'drm_atomic_connector_check': /kisskb/src/drivers/gpu/drm/drm_atomic.c:420:38: warning: 'crtc_state' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/gpu/drm/drm_atomic.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/net/sctp/output.c: In function 'sctp_packet_config': /kisskb/src/include/net/sock.h:1942:19: warning: 'sk' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/sctp/output.c:94:15: note: 'sk' was declared here /kisskb/src/net/sctp/output.c: At top level: cc1: warning: unrecognized command line option "-Wno-maybe-uninitialized" [enabled by default] /kisskb/src/lib/string.c: In function 'strnstr': /kisskb/src/lib/string.c:479:8: sorry, unimplemented: inlining failed in call to 'strlen': redefined extern inline functions are not considered for inlining /kisskb/src/lib/string.c:930:5: sorry, unimplemented: called from here make[2]: *** [/kisskb/src/scripts/Makefile.build:277: lib/string.o] Error 1 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [/kisskb/src/Makefile:1042: lib] Error 2 make: *** [Makefile:152: sub-make] Error 2 Command 'make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_powerpc-randconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- ' returned non-zero exit status 2 # rm -rf /kisskb/build/powerpc-fixes_powerpc-randconfig_powerpc-gcc4.6 # Build took: 0:00:59.357668