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authorEric W. Biederman <ebiederm@xmission.com>2021-10-20 12:44:01 -0500
committerEric W. Biederman <ebiederm@xmission.com>2021-10-29 14:31:33 -0500
commitc317d306d55079525c9610267fdaf3a8a6d2f08b (patch)
tree01cd791c41ea3d1b1f97784eb10d8c68ce3be531 /arch/sparc
parent941edc5bf174b67f94db19817cbeab0a93e0c32a (diff)
downloadlinux-c317d306d55079525c9610267fdaf3a8a6d2f08b.tar.bz2
signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails
The function try_to_clear_window_buffer is only called from rtrap_32.c. After it is called the signal pending state is retested, and signals are handled if TIF_SIGPENDING is set. This allows try_to_clear_window_buffer to call force_fatal_signal and then rely on the signal being delivered to kill the process, without any danger of returning to userspace, or otherwise using possible corrupt state on failure. The functional difference between force_fatal_sig and do_exit is that do_exit will only terminate a single thread, and will never trigger a core-dump. A multi-threaded program for which a single thread terminates unexpectedly is hard to reason about. Calling force_fatal_sig does not give userspace a chance to catch the signal, but otherwise is an ordinary fatal signal exit, and it will trigger a coredump of the offending process if core dumps are enabled. Cc: David Miller <davem@davemloft.net> Cc: sparclinux@vger.kernel.org Link: https://lkml.kernel.org/r/20211020174406.17889-15-ebiederm@xmission.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'arch/sparc')
-rw-r--r--arch/sparc/kernel/windows.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/sparc/kernel/windows.c b/arch/sparc/kernel/windows.c
index 69a6ba6e9293..bbbd40cc6b28 100644
--- a/arch/sparc/kernel/windows.c
+++ b/arch/sparc/kernel/windows.c
@@ -121,8 +121,10 @@ void try_to_clear_window_buffer(struct pt_regs *regs, int who)
if ((sp & 7) ||
copy_to_user((char __user *) sp, &tp->reg_window[window],
- sizeof(struct reg_window32)))
- do_exit(SIGILL);
+ sizeof(struct reg_window32))) {
+ force_fatal_sig(SIGILL);
+ return;
+ }
}
tp->w_saved = 0;
}