Re: kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call without frame pointer save/setup
On Tue, Aug 27, 2019 at 10:43:27AM +0800, He Zhe wrote:
>
>
> On 8/26/19 11:18 PM, Josh Poimboeuf wrote:
> > On Mon, Aug 26, 2019 at 10:42:53PM +0800, He Zhe wrote:
> >> Hi All,
> >>
> >> Since 3193c0836f20 ("bpf: Disable GCC -fgcse optimization for
> >> ___bpf_prog_run()"),
> >> We have got the following warning,
> >> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call
> >> without frame pointer save/setup
> >>
> >> If reverting the above commit, we will get the following warning,
> >> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x8b9: sibling call
> >> from callable instruction with modified stack frame
> >> if CONFIG_RETPOLINE=n, and no warning if CONFIG_RETPOLINE=y
> > Can you please share the following:
> >
> > - core.o file
>
> Attached.
>
> >
> > The following would also be helpful for me to try to recreate it:
> >
> > - config file
> > - compiler version
> > - kernel version
>
> I pasted them in the other reply.
Thanks. I was able to recreate. I reduced it to:
void a(b);
__attribute__((optimize(""))) c(void) { a(); }
Apparently '__attribute__((optimize()))' is overwriting GCC cmdline
flags, including -fno-omit-frame-pointer. I had assumed it would append
instead of replace.
I'm guessing this is a GCC "feature" instead of a bug. I'll need to
follow up.
--
Josh
Re: kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call without frame pointer save/setup
On 8/26/19 11:11 PM, Greg KH wrote:
> On Mon, Aug 26, 2019 at 10:42:53PM +0800, He Zhe wrote:
>> Hi All,
>>
>> Since 3193c0836f20 ("bpf: Disable GCC -fgcse optimization for
>> ___bpf_prog_run()"),
>> We have got the following warning,
>> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call
>> without frame pointer save/setup
>>
>> If reverting the above commit, we will get the following warning,
>> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x8b9: sibling call
>> from callable instruction with modified stack frame
>> if CONFIG_RETPOLINE=n, and no warning if CONFIG_RETPOLINE=y
> Do you see this same problem on 5.3-rc6?
>
> And what version of gcc are you using?
Sorry for missing such information.
Here is the .config along with kernel and GCC version.
#
# Automatically generated file; DO NOT EDIT.
# Linux/x86 5.3.0-rc6 Kernel Configuration
#
#
# Compiler: x86_64-wrs-linux-gcc (GCC) 9.1.0
#
CONFIG_CC_IS_GCC=y
CONFIG_GCC_VERSION=90100
CONFIG_CLANG_VERSION=0
CONFIG_CC_HAS_ASM_GOTO=y
CONFIG_CC_HAS_WARN_MAYBE_UNINITIALIZED=y
CONFIG_IRQ_WORK=y
CONFIG_BUILDTIME_EXTABLE_SORT=y
CONFIG_THREAD_INFO_IN_TASK=y
#
# General setup
#
CONFIG_INIT_ENV_ARG_LIMIT=32
# CONFIG_COMPILE_TEST is not set
# CONFIG_HEADER_TEST is not set
CONFIG_LOCALVERSION="dev"
# CONFIG_LOCALVERSION_AUTO is not set
CONFIG_BUILD_SALT=""
CONFIG_HAVE_KERNEL_GZIP=y
CONFIG_HAVE_KERNEL_BZIP2=y
CONFIG_HAVE_KERNEL_LZMA=y
CONFIG_HAVE_KERNEL_XZ=y
CONFIG_HAVE_KERNEL_LZO=y
CONFIG_HAVE_KERNEL_LZ4=y
CONFIG_KERNEL_GZIP=y
# CONFIG_KERNEL_BZIP2 is not set
# CONFIG_KERNEL_LZMA is not set
# CONFIG_KERNEL_XZ is not set
# CONFIG_KERNEL_LZO is not set
# CONFIG_KERNEL_LZ4 is not set
CONFIG_DEFAULT_HOSTNAME="(none)"
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
CONFIG_SYSVIPC_SYSCTL=y
CONFIG_POSIX_MQUEUE=y
CONFIG_POSIX_MQUEUE_SYSCTL=y
CONFIG_CROSS_MEMORY_ATTACH=y
CONFIG_USELIB=y
CONFIG_AUDIT=y
CONFIG_HAVE_ARCH_AUDITSYSCALL=y
CONFIG_AUDITSYSCALL=y
#
# IRQ subsystem
#
CONFIG_GENERIC_IRQ_PROBE=y
CONFIG_GENERIC_IRQ_SHOW=y
CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK=y
CONFIG_GENERIC_PENDING_IRQ=y
CONFIG_GENERIC_IRQ_MIGRATION=y
CONFIG_IRQ_DOMAIN=y
CONFIG_IRQ_DOMAIN_HIERARCHY=y
CONFIG_GENERIC_MSI_IRQ=y
CONFIG_GENERIC_MSI_IRQ_DOMAIN=y
CONFIG_GENERIC_IRQ_MATRIX_ALLOCATOR=y
CONFIG_GENERIC_IRQ_RESERVATION_MODE=y
CONFIG_IRQ_FORCED_THREADING=y
CONFIG_SPARSE_IRQ=y
# CONFIG_GENERIC_IRQ_DEBUGFS is not set
# end of IRQ subsystem
CONFIG_CLOCKSOURCE_WATCHDOG=y
CONFIG_ARCH_CLOCKSOURCE_DATA=y
CONFIG_ARCH_CLOCKSOURCE_INIT=y
CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE=y
CONFIG_GENERIC_TIME_VSYSCALL=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y
CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST=y
CONFIG_GENERIC_CMOS_UPDATE=y
#
# Timers subsystem
#
CONFIG_TICK_ONESHOT=y
CONFIG_NO_HZ_COMMON=y
# CONFIG_HZ_PERIODIC is not set
# CONFIG_NO_HZ_IDLE is not set
CONFIG_NO_HZ_FULL=y
CONFIG_CONTEXT_TRACKING=y
# CONFIG_CONTEXT_TRACKING_FORCE is not set
CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y
# end of Timers subsystem
CONFIG_PREEMPT_NONE=y
# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT is not set
#
# CPU/Task time and stats accounting
#
CONFIG_VIRT_CPU_ACCOUNTING=y
CONFIG_VIRT_CPU_ACCOUNTING_GEN=y
# CONFIG_IRQ_TIME_ACCOUNTING is not set
CONFIG_BSD_PROCESS_ACCT=y
CONFIG_BSD_PROCESS_ACCT_V3=y
CONFIG_TASKSTATS=y
CONFIG_TASK_DELAY_ACCT=y
CONFIG_TASK_XACCT=y
CONFIG_TASK_IO_ACCOUNTING=y
# CONFIG_PSI is not set
# end of CPU/Task time and stats accounting
CONFIG_CPU_ISOLATION=y
#
# RCU Subsystem
#
CONFIG_TREE_RCU=y
# CONFIG_RCU_EXPERT is not set
CONFIG_SRCU=y
CONFIG_TREE_SRCU=y
CONFIG_RCU_STALL_COMMON=y
CONFIG_RCU_NEED_SEGCBLIST=y
CONFIG_RCU_NOCB_CPU=y
# end of RCU Subsystem
CONFIG_IKCONFIG=y
CONFIG_IKCONFIG_PROC=y
# CONFIG_IKHEADERS is not set
CONFIG_LOG_BUF_SHIFT=17
CONFIG_LOG_CPU_MAX_BUF_SHIFT=12
CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT=13
CONFIG_HAVE_UNSTABLE_SCHED_CLOCK=y
#
# Scheduler features
#
# end of Scheduler features
CONFIG_ARCH_SUPPORTS_NUMA_BALANCING=y
CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH=y
CONFIG_ARCH_SUPPORTS_INT128=y
CONFIG_NUMA_BALANCING=y
CONFIG_NUMA_BALANCING_DEFAULT_ENABLED=y
CONFIG_CGROUPS=y
CONFIG_PAGE_COUNTER=y
CONFIG_MEMCG=y
CONFIG_MEMCG_SWAP=y
CONFIG_MEMCG_SWAP_ENABLED=y
CONFIG_MEMCG_KMEM=y
CONFIG_BLK_CGROUP=y
CONFIG_CGROUP_WRITEBACK=y
CONFIG_CGROUP_SCHED=y
CONFIG_FAIR_GROUP_SCHED=y
CONFIG_CFS_BANDWIDTH=y
CONFIG_RT_GROUP_SCHED=y
CONFIG_CGROUP_PIDS=y
# CONFIG_CGROUP_RDMA is not set
CONFIG_CGROUP_FREEZER=y
# CONFIG_CGROUP_HUGETLB is not set
CONFIG_CPUSETS=y
CONFIG_PROC_PID_CPUSET=y
CONFIG_CGROUP_DEVICE=y
CONFIG_CGROUP_CPUACCT=y
CONFIG_CGROUP_PERF=y
CONFIG_CGROUP_BPF=y
CONFIG_CGROUP_DEBUG=y
CONFIG_SOCK_CGROUP_DATA=y
CONFIG_NAMESPACES=y
CONFIG_UTS_NS=y
CONFIG_IPC_NS=y
CONFIG_USER_NS=y
CONFIG_PID_NS=y
CONFIG_NET_NS=y
CONFIG_CHECKPOINT_RESTORE=y
# CONFIG_SCHED_AUTOGROUP is not set
# CONFIG_SYSFS_DEPRECATED is not set
CONFIG_RELAY=y
CONFIG_
Re: kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call without frame pointer save/setup
On Mon, Aug 26, 2019 at 10:42:53PM +0800, He Zhe wrote:
> Hi All,
>
> Since 3193c0836f20 ("bpf: Disable GCC -fgcse optimization for
> ___bpf_prog_run()"),
> We have got the following warning,
> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call without
> frame pointer save/setup
>
> If reverting the above commit, we will get the following warning,
> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x8b9: sibling call
> from callable instruction with modified stack frame
> if CONFIG_RETPOLINE=n, and no warning if CONFIG_RETPOLINE=y
Can you please share the following:
- core.o file
The following would also be helpful for me to try to recreate it:
- config file
- compiler version
- kernel version
--
Josh
Re: kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call without frame pointer save/setup
On Mon, Aug 26, 2019 at 10:42:53PM +0800, He Zhe wrote:
> Hi All,
>
> Since 3193c0836f20 ("bpf: Disable GCC -fgcse optimization for
> ___bpf_prog_run()"),
> We have got the following warning,
> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call without
> frame pointer save/setup
>
> If reverting the above commit, we will get the following warning,
> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x8b9: sibling call
> from callable instruction with modified stack frame
> if CONFIG_RETPOLINE=n, and no warning if CONFIG_RETPOLINE=y
Do you see this same problem on 5.3-rc6?
And what version of gcc are you using?
thanks,
greg k-h
kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call without frame pointer save/setup
Hi All,
Since 3193c0836f20 ("bpf: Disable GCC -fgcse optimization for
___bpf_prog_run()"),
We have got the following warning,
kernel/bpf/core.o: warning: objtool: ___bpf_prog_run.cold()+0x7: call without
frame pointer save/setup
If reverting the above commit, we will get the following warning,
kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x8b9: sibling call from
callable instruction with modified stack frame
if CONFIG_RETPOLINE=n, and no warning if CONFIG_RETPOLINE=y
Zhe
