The patch titled
Subject: kmod: make __request_module() killable
has been removed from the -mm tree. Its filename was
kmod-make-__request_module-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: kmod: make __request_module() killable
As Tetsuo Handa pointed out, request_module() can stress the system while
the oom-killed caller sleeps in TASK_UNINTERRUPTIBLE.
The task T uses "almost all" memory, then it does something which triggers
request_module(). Say, it can simply call sys_socket(). This in turn
needs more memory and leads to OOM. oom-killer correctly chooses T and
kills it, but this can't help because it sleeps in TASK_UNINTERRUPTIBLE
and after that oom-killer becomes "disabled" by the TIF_MEMDIE task T.
Make __request_module() killable. The only necessary change is that
call_modprobe() should kmalloc argv and module_name, they can't live in
the stack if we use UMH_KILLABLE. This memory is freed via
call_usermodehelper_freeinfo()->cleanup.
Reported-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kmod.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
diff -puN kernel/kmod.c~kmod-make-__request_module-killable kernel/kmod.c
--- a/kernel/kmod.c~kmod-make-__request_module-killable
+++ a/kernel/kmod.c
@@ -60,6 +60,12 @@ static DECLARE_RWSEM(umhelper_sem);
*/
char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe";
+static void free_modprobe_argv(struct subprocess_info *info)
+{
+ kfree(info->argv[3]); /* check call_modprobe() */
+ kfree(info->argv);
+}
+
static int call_modprobe(char *module_name, int wait)
{
static char *envp[] = {
@@ -69,10 +75,26 @@ static int call_modprobe(char *module_na
NULL
};
- char *argv[] = { modprobe_path, "-q", "--", module_name, NULL };
+ char **argv = kmalloc(sizeof(char *[5]), GFP_KERNEL);
+ if (!argv)
+ goto out;
+
+ module_name = kstrdup(module_name, GFP_KERNEL);
+ if (!module_name)
+ goto free_argv;
+
+ argv[0] = modprobe_path;
+ argv[1] = "-q";
+ argv[2] = "--";
+ argv[3] = module_name; /* check free_modprobe_argv() */
+ argv[4] = NULL;
return call_usermodehelper_fns(modprobe_path, argv, envp,
- wait, NULL, NULL, NULL);
+ wait | UMH_KILLABLE, NULL, free_modprobe_argv, NULL);
+free_argv:
+ kfree(argv);
+out:
+ return -ENOMEM;
}
/**
_
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
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