Commit breaks strace: ARM: entry: allow ARM-private syscalls to be restarted
Jason Gunthorpe
jgunthorpe at obsidianresearch.com
Tue Sep 17 17:57:49 EDT 2013
Hi Will,
I was just testing v3.12-rc1 (on kirkwood) and noticed that strace is
not working:
$ strace /bin/ls
mmap2(0xb6f79000, 9552, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6f79000
close(3) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb6fad000
set_tls(0xb6fad4c0, 0xb6fadb98, 0xb6fb1050, 0xb6fad4c0, 0xb6fb1050) = -1 ENOSYS (Function not implemented)
writev(2, [{"cannot set up thread-local stora"..., 36}, {"unknown error", 13}, {"\n", 1}], 3cannot set up thread-local storage: unknown error
) = 50
exit_group(127) = ?
+++ exited with 127 +++
I determined that reverting your commit below makes strace work again.
I've tested 3.10.12 and it is OK.
This happens with the latest git head for strace, as well as the 4.7
release.
Hopefully you can cook up a fix :)
Regards,
Jason
commit 377747c40657eb35ad98a56439606d96a928425a
Author: Will Deacon <will.deacon at arm.com>
Date: Mon May 13 19:16:34 2013 +0100
ARM: entry: allow ARM-private syscalls to be restarted
System calls will only be restarted after signal handling if they (a)
return an error code indicating that a restart is required and (b) have
`why' set to a non-zero value, to indicate that the signal interrupted
them.
This patch leaves `why' set to a non-zero value for ARM-private syscalls
, and only zeroes it for syscalls that are not implemented.
Signed-off-by: Will Deacon <will.deacon at arm.com>
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 94104bf..74ad15d1 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -442,10 +442,10 @@ local_restart:
ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
add r1, sp, #S_OFF
-2: mov why, #0 @ no longer a real syscall
cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
- bcs arm_syscall
+ bcs arm_syscall
+2: mov why, #0 @ no longer a real syscall
b sys_ni_syscall @ not private func
#if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
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