diff options
| author | Will Deacon <will.deacon@arm.com> | 2018-09-05 15:34:42 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2018-10-01 11:43:55 +0100 |
| commit | 22839869f21ab3850fbbac9b425ccc4c0023926f (patch) | |
| tree | 0400aeeaafa9c71b5378185043e37429c6db6b8d /include/linux/compat.h | |
| parent | 03630b3b76ccc2999f77e11c4ba60b0a549d023a (diff) | |
signal: Introduce COMPAT_SIGMINSTKSZ for use in compat_sys_sigaltstack
The sigaltstack(2) system call fails with -ENOMEM if the new alternative
signal stack is found to be smaller than SIGMINSTKSZ. On architectures
such as arm64, where the native value for SIGMINSTKSZ is larger than
the compat value, this can result in an unexpected error being reported
to a compat task. See, for example:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=904385
This patch fixes the problem by extending do_sigaltstack to take the
minimum signal stack size as an additional parameter, allowing the
native and compat system call entry code to pass in their respective
values. COMPAT_SIGMINSTKSZ is just defined as SIGMINSTKSZ if it has not
been defined by the architecture.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Reported-by: Steve McIntyre <steve.mcintyre@arm.com>
Tested-by: Steve McIntyre <93sam@debian.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'include/linux/compat.h')
| -rw-r--r-- | include/linux/compat.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/compat.h b/include/linux/compat.h index 1a3c4f37e908..de0c13bdcd2c 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -103,6 +103,9 @@ typedef struct compat_sigaltstack { compat_size_t ss_size; } compat_stack_t; #endif +#ifndef COMPAT_MINSIGSTKSZ +#define COMPAT_MINSIGSTKSZ MINSIGSTKSZ +#endif #define compat_jiffies_to_clock_t(x) \ (((unsigned long)(x) * COMPAT_USER_HZ) / HZ) |