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authorEric W. Biederman <ebiederm@xmission.com>2021-10-20 12:43:52 -0500
committerEric W. Biederman <ebiederm@xmission.com>2021-10-25 15:56:29 -0500
commitce0ee4e6ac99606f3945f4d47775544edc3f7985 (patch)
tree1333aa77192bfb29903ddecb2f8774b59380325b /arch/sh
parent95bf9d646c3c3f95cb0be7e703b371db8da5be68 (diff)
downloadlinux-ce0ee4e6ac99606f3945f4d47775544edc3f7985.tar.bz2
signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL)
Today the sh code allocates memory the first time a process uses the fpu. If that memory allocation fails, kill the affected task with force_sig(SIGKILL) rather than do_group_exit(SIGKILL). Calling do_group_exit from an exception handler can potentially lead to dead locks as do_group_exit is not designed to be called from interrupt context. Instead use force_sig(SIGKILL) to kill the userspace process. Sending signals in general and force_sig in particular has been tested from interrupt context so there should be no problems. Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: linux-sh@vger.kernel.org Fixes: 0ea820cf9bf5 ("sh: Move over to dynamically allocated FPU context.") Link: https://lkml.kernel.org/r/20211020174406.17889-6-ebiederm@xmission.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'arch/sh')
-rw-r--r--arch/sh/kernel/cpu/fpu.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/sh/kernel/cpu/fpu.c b/arch/sh/kernel/cpu/fpu.c
index ae354a2931e7..fd6db0ab1928 100644
--- a/arch/sh/kernel/cpu/fpu.c
+++ b/arch/sh/kernel/cpu/fpu.c
@@ -62,18 +62,20 @@ void fpu_state_restore(struct pt_regs *regs)
}
if (!tsk_used_math(tsk)) {
- local_irq_enable();
+ int ret;
/*
* does a slab alloc which can sleep
*/
- if (init_fpu(tsk)) {
+ local_irq_enable();
+ ret = init_fpu(tsk);
+ local_irq_disable();
+ if (ret) {
/*
* ran out of memory!
*/
- do_group_exit(SIGKILL);
+ force_sig(SIGKILL);
return;
}
- local_irq_disable();
}
grab_fpu(regs);