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Commit b934069c authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

[S390] add missing .set function for NT_S390_LAST_BREAK regset 



The last breaking event address is a read-only value, the regset misses the
.set function. If a PTRACE_SETREGSET is done for NT_S390_LAST_BREAK we
get an oops due to a branch to zero:

Kernel BUG at 0000000000000002 verbose debug info unavailable
illegal operation: 0001 #1 SMP
...
Call Trace:
(<0000000000158294> ptrace_regset+0x184/0x188)
 <00000000001595b6> ptrace_request+0x37a/0x4fc
 <0000000000109a78> arch_ptrace+0x108/0x1fc
 <00000000001590d6> SyS_ptrace+0xaa/0x12c
 <00000000005c7a42> sysc_noemu+0x16/0x1c
 <000003fffd5ec10c> 0x3fffd5ec10c
Last Breaking-Event-Address:
 <0000000000158242> ptrace_regset+0x132/0x188

Add a nop .set function to prevent the branch to zero.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Cc: stable@kernel.org
parent 7c81878b

arch/s390/kernel/ptrace.c

+18 −0
Original line number Diff line number Diff line
@@ -905,6 +905,14 @@ static int s390_last_break_get(struct task_struct *target, 
	return 0;

}



static int s390_last_break_set(struct task_struct *target,

			       const struct user_regset *regset,

			       unsigned int pos, unsigned int count,

			       const void *kbuf, const void __user *ubuf)

{

	return 0;

}



#endif



static int s390_system_call_get(struct task_struct *target,
@@ -951,6 +959,7 @@ static const struct user_regset s390_regsets[] = { 
		.size = sizeof(long),

		.align = sizeof(long),

		.get = s390_last_break_get,

		.set = s390_last_break_set,

	},

#endif

	[REGSET_SYSTEM_CALL] = {
@@ -1116,6 +1125,14 @@ static int s390_compat_last_break_get(struct task_struct *target, 
	return 0;

}



static int s390_compat_last_break_set(struct task_struct *target,

				      const struct user_regset *regset,

				      unsigned int pos, unsigned int count,

				      const void *kbuf, const void __user *ubuf)

{

	return 0;

}



static const struct user_regset s390_compat_regsets[] = {

	[REGSET_GENERAL] = {

		.core_note_type = NT_PRSTATUS,
@@ -1139,6 +1156,7 @@ static const struct user_regset s390_compat_regsets[] = { 
		.size = sizeof(long),

		.align = sizeof(long),

		.get = s390_compat_last_break_get,

		.set = s390_compat_last_break_set,

	},

	[REGSET_SYSTEM_CALL] = {

		.core_note_type = NT_S390_SYSTEM_CALL,