The patch titled Subject: usermodehelper: implement UMH_KILLABLE has been removed from the -mm tree. Its filename was usermodehelper-implement-umh_killable.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ From: Oleg Nesterov <oleg@xxxxxxxxxx> Subject: usermodehelper: implement UMH_KILLABLE Implement UMH_KILLABLE, should be used along with UMH_WAIT_EXEC/PROC. The caller must ensure that subprocess_info->path/etc can not go away until call_usermodehelper_freeinfo(). call_usermodehelper_exec(UMH_KILLABLE) does wait_for_completion_killable. If it fails, it uses xchg(&sub_info->complete, NULL) to serialize with umh_complete() which does the same xhcg() to access sub_info->complete. If call_usermodehelper_exec wins, it can safely return. umh_complete() should get NULL and call call_usermodehelper_freeinfo(). Otherwise we know that umh_complete() was already called, in this case call_usermodehelper_exec() falls back to wait_for_completion() which should succeed "very soon". Note: UMH_NO_WAIT == -1 but it obviously should not be used with UMH_KILLABLE. We delay the neccessary cleanup to simplify the back porting. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/kmod.h | 2 ++ kernel/kmod.c | 27 +++++++++++++++++++++++++-- 2 files changed, 27 insertions(+), 2 deletions(-) diff -puN include/linux/kmod.h~usermodehelper-implement-umh_killable include/linux/kmod.h --- a/include/linux/kmod.h~usermodehelper-implement-umh_killable +++ a/include/linux/kmod.h @@ -54,6 +54,8 @@ enum umh_wait { UMH_WAIT_PROC = 1, /* wait for the process to complete */ }; +#define UMH_KILLABLE 4 /* wait for EXEC/PROC killable */ + struct subprocess_info { struct work_struct work; struct completion *complete; diff -puN kernel/kmod.c~usermodehelper-implement-umh_killable kernel/kmod.c --- a/kernel/kmod.c~usermodehelper-implement-umh_killable +++ a/kernel/kmod.c @@ -201,7 +201,15 @@ EXPORT_SYMBOL(call_usermodehelper_freein static void umh_complete(struct subprocess_info *sub_info) { - complete(sub_info->complete); + struct completion *comp = xchg(&sub_info->complete, NULL); + /* + * See call_usermodehelper_exec(). If xchg() returns NULL + * we own sub_info, the UMH_KILLABLE caller has gone away. + */ + if (comp) + complete(comp); + else + call_usermodehelper_freeinfo(sub_info); } /* Keventd can't block, but this (a child) can. */ @@ -252,6 +260,9 @@ static void __call_usermodehelper(struct enum umh_wait wait = sub_info->wait; pid_t pid; + if (wait != UMH_NO_WAIT) + wait &= ~UMH_KILLABLE; + /* CLONE_VFORK: wait until the usermode helper has execve'd * successfully We need the data structures to stay around * until that is done. */ @@ -461,9 +472,21 @@ int call_usermodehelper_exec(struct subp queue_work(khelper_wq, &sub_info->work); if (wait == UMH_NO_WAIT) /* task has freed sub_info */ goto unlock; + + if (wait & UMH_KILLABLE) { + retval = wait_for_completion_killable(&done); + if (!retval) + goto wait_done; + + /* umh_complete() will see NULL and free sub_info */ + if (xchg(&sub_info->complete, NULL)) + goto unlock; + /* fallthrough, umh_complete() was already called */ + } + wait_for_completion(&done); +wait_done: retval = sub_info->retval; - out: call_usermodehelper_freeinfo(sub_info); unlock: _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are origin.patch linux-next.patch avr32-dont-mask-signals-in-the-error-path.patch avr32-use-set_current_blocked-in-handle_signal-sys_rt_sigreturn.patch avr32-use-block_sigmask.patch ia64-use-set_current_blocked-and-block_sigmask.patch microblaze-dont-reimplement-force_sigsegv.patch microblaze-no-need-to-reset-handler-if-sa_oneshot.patch microblaze-fix-signal-masking.patch microblaze-use-set_current_blocked-and-block_sigmask.patch mips-use-set_current_blocked-and-block_sigmask.patch score-dont-mask-signals-if-we-fail-to-setup-signal-stack.patch score-use-set_current_blocked-and-block_sigmask.patch unicore32-use-block_sigmask.patch blackfin-use-set_current_blocked-and-block_sigmask.patch parisc-use-set_current_blocked-and-block_sigmask.patch mm-coredump-fail-allocations-when-coredumping-instead-of-oom-killing.patch frv-use-set_current_blocked-and-block_sigmask.patch sh-no-need-to-reset-handler-if-sa_oneshot.patch sh-use-set_current_blocked-and-block_sigmask.patch h8300-use-set_current_blocked-and-block_sigmask.patch alpha-use-set_current_blocked-and-block_sigmask.patch m32r-use-set_current_blocked-and-block_sigmask.patch m68k-use-set_current_blocked-and-block_sigmask.patch mn10300-use-set_current_blocked-and-block_sigmask.patch c6x-use-set_current_blocked-and-block_sigmask.patch cris-use-set_current_blocked-and-block_sigmask.patch powerpc-eeh-remove-eeh_event_handler-daemonize.patch pidns-add-reboot_pid_ns-to-handle-the-reboot-syscall.patch pidns-add-reboot_pid_ns-to-handle-the-reboot-syscall-fix.patch sysctl-make-kernelns_last_pid-control-being-checkpoint_restore-dependent.patch fs-proc-introduce-proc-pid-task-tid-children-entry-v9.patch c-r-prctl-add-ability-to-set-new-mm_struct-exe_file.patch c-r-prctl-add-ability-to-get-clear_tid_address.patch c-r-prctl-add-ability-to-get-clear_tid_address-fix.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html