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| author |   Bodo Stroesser <bstroesser@fujitsu-siemens.com> | 2005-05-06 21:30:54 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-05-06 22:09:30 -0700 |
| commit | 0f7e663dea7f0e22f3b2d07156c5e9d2e8656610 (patch) | |
| tree | 669450b10e1677d3ea65aa7695a7834f791ce329 /arch/um/kernel/skas | |
| parent | [PATCH] uml: S390 preparation, arch_align_stack (diff) | |
| download | linux-dev-0f7e663dea7f0e22f3b2d07156c5e9d2e8656610.tar.xz linux-dev-0f7e663dea7f0e22f3b2d07156c5e9d2e8656610.zip | |
[PATCH] uml: Fix process exit race
tt-mode closes switch_pipes in exit_thread_tt and kills processes in
switch_to_tt, if the exit_state is EXIT_DEAD or EXIT_ZOMBIE.
In very rare cases the exiting process can be scheduled out after having set
exit_state and closed switch_pipes (from release_task it calls proc_pid_flush,
which might sleep). If this process is to be restarted, UML failes in
switch_to_tt with:
write of switch_pipe failed, err = 9
We fix this by closing switch_pipes not in exit_thread_tt, but later in
release_thread_tt. Additionally, we set switch_pipe[0] = 0 after closing.
switch_to_tt must not kill "from" process depending on its exit_state, but
must kill it after release_thread was processed only, so it examines
switch_pipe[0] for its decision.
Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/um/kernel/skas')
| -rw-r--r-- | arch/um/kernel/skas/include/mode_kern-skas.h | 1 | ||||
| -rw-r--r-- | arch/um/kernel/skas/process_kern.c | 4 |
2 files changed, 0 insertions, 5 deletions
diff --git a/arch/um/kernel/skas/include/mode_kern-skas.h b/arch/um/kernel/skas/include/mode_kern-skas.h index 94c564962378..e48490028111 100644 --- a/arch/um/kernel/skas/include/mode_kern-skas.h +++ b/arch/um/kernel/skas/include/mode_kern-skas.h @@ -18,7 +18,6 @@ extern int copy_thread_skas(int nr, unsigned long clone_flags, unsigned long sp, unsigned long stack_top, struct task_struct *p, struct pt_regs *regs); extern void release_thread_skas(struct task_struct *task); -extern void exit_thread_skas(void); extern void initial_thread_cb_skas(void (*proc)(void *), void *arg); extern void init_idle_skas(void); extern void flush_tlb_kernel_range_skas(unsigned long start, diff --git a/arch/um/kernel/skas/process_kern.c b/arch/um/kernel/skas/process_kern.c index 5d096ea63b97..ab5d3271da0b 100644 --- a/arch/um/kernel/skas/process_kern.c +++ b/arch/um/kernel/skas/process_kern.c @@ -83,10 +83,6 @@ void release_thread_skas(struct task_struct *task) { } -void exit_thread_skas(void) -{ -} - void fork_handler(int sig) { change_sig(SIGUSR1, 1); |