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| author | Eric W. Biederman <ebiederm@xmission.com> | 2017-07-16 20:04:58 -0500 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2017-07-19 19:13:14 -0500 |
| commit | cc9f72e474a4da365896d0e528da324f205e8b31 (patch) | |
| tree | cda3b38a86ae57b171c6094a6ef405b17ac75260 /arch | |
| parent | 80dce5e37493029e1fb7f890b960264ba9a46fe4 (diff) | |
| download | op-kernel-dev-cc9f72e474a4da365896d0e528da324f205e8b31.zip op-kernel-dev-cc9f72e474a4da365896d0e528da324f205e8b31.tar.gz | |
signal/sparc: Document a conflict with SI_USER with SIGFPE
Setting si_code to __SI_FAULT results in a userspace seeing
an si_code of 0. This is the same si_code as SI_USER. Posix
and common sense requires that SI_USER not be a signal specific
si_code. As such this use of 0 for the si_code is a pretty
horribly broken ABI.
This was introduced in 2.3.41 so this mess has had a long time for
people to be able to start depending on it.
As this bug has existed for 17 years already I don't know if it is
worth fixing. It is definitely worth documenting what is going
on so that no one decides to copy this bad decision.
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/sparc/include/uapi/asm/siginfo.h | 7 | ||||
| -rw-r--r-- | arch/sparc/kernel/traps_32.c | 2 | ||||
| -rw-r--r-- | arch/sparc/kernel/traps_64.c | 2 |
3 files changed, 9 insertions, 2 deletions
diff --git a/arch/sparc/include/uapi/asm/siginfo.h b/arch/sparc/include/uapi/asm/siginfo.h index 2d9b79cc..da2126e 100644 --- a/arch/sparc/include/uapi/asm/siginfo.h +++ b/arch/sparc/include/uapi/asm/siginfo.h @@ -17,6 +17,13 @@ #define SI_NOINFO 32767 /* no information in siginfo_t */ /* + * SIGFPE si_codes + */ +#ifdef __KERNEL__ +#define FPE_FIXME (__SI_FAULT|0) /* Broken dup of SI_USER */ +#endif /* __KERNEL__ */ + +/* * SIGEMT si_codes */ #define EMT_TAGOVF (__SI_FAULT|1) /* tag overflow */ diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c index 466d4ae..581cf35 100644 --- a/arch/sparc/kernel/traps_32.c +++ b/arch/sparc/kernel/traps_32.c @@ -306,7 +306,7 @@ void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc, info.si_errno = 0; info.si_addr = (void __user *)pc; info.si_trapno = 0; - info.si_code = __SI_FAULT; + info.si_code = FPE_FIXME; if ((fsr & 0x1c000) == (1 << 14)) { if (fsr & 0x10) info.si_code = FPE_FLTINV; diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c index 196ee5e..e882e12 100644 --- a/arch/sparc/kernel/traps_64.c +++ b/arch/sparc/kernel/traps_64.c @@ -2258,7 +2258,7 @@ static void do_fpe_common(struct pt_regs *regs) info.si_errno = 0; info.si_addr = (void __user *)regs->tpc; info.si_trapno = 0; - info.si_code = __SI_FAULT; + info.si_code = FPE_FIXME; if ((fsr & 0x1c000) == (1 << 14)) { if (fsr & 0x10) info.si_code = FPE_FLTINV; |
