evie/android_kernel_oneplus_msm8998
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CHROMIUM: android: binder: Fix potential scheduling-while-atomic

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Commit f1e7f0a724f6 ("android: binder: Disable preemption while holding
the global binder lock.") re-enabled preemption around most of the sites
where calls to potentially sleeping functions were made, but missed
__alloc_fd(), which can sleep if the fdtable needs to be resized.
Re-enable preemption around __alloc_fd() as well as __fd_install() which
can now sleep in upstream kernels as of commit 8a81252b77 ("fs/file.c:
don't acquire files->file_lock in fd_install()").

BUG=chrome-os-partner:44012
TEST=Build and boot on Smaug.

Change-Id: I9819c4b95876f697e75b1b84810b6c520d9c33ec
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/308582
Reviewed-by: Stephen Barber <smbarber@chromium.org>
Reviewed-by: Riley Andrews <riandrews@google.com>
Git-repo: https://source.codeaurora.org/quic/la/kernel/msm-4.4
Git-commit: c267ff1d548ed1bdad6a08f1c70776c5e60d569e
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
This commit is contained in:
Andrew Bresticker 2015-10-23 15:13:42 -07:00 • committed by Vikram Mulukutla
parent e4045d607a
commit 821e02f204
1 changed files with 10 additions and 2 deletions
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12
drivers/android/binder.c
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@ -379,6 +379,7 @@ static int task_get_unused_fd_flags(struct binder_proc *proc, int flags)
struct files_struct *files = proc->files; struct files_struct *files = proc->files;
unsigned long rlim_cur; unsigned long rlim_cur;
unsigned long irqs; unsigned long irqs;
int ret;
if (files == NULL) if (files == NULL)
return -ESRCH; return -ESRCH;
@ -389,7 +390,11 @@ static int task_get_unused_fd_flags(struct binder_proc *proc, int flags)
rlim_cur = task_rlimit(proc->tsk, RLIMIT_NOFILE); rlim_cur = task_rlimit(proc->tsk, RLIMIT_NOFILE);
unlock_task_sighand(proc->tsk, &irqs); unlock_task_sighand(proc->tsk, &irqs);
return __alloc_fd(files, 0, rlim_cur, flags); preempt_enable_no_resched();
ret = __alloc_fd(files, 0, rlim_cur, flags);
preempt_disable();
return ret;
} }
/* /*
@ -398,8 +403,11 @@ static int task_get_unused_fd_flags(struct binder_proc *proc, int flags)
static void task_fd_install( static void task_fd_install(
struct binder_proc *proc, unsigned int fd, struct file *file) struct binder_proc *proc, unsigned int fd, struct file *file)
{ {
if (proc->files) if (proc->files) {
preempt_enable_no_resched();
__fd_install(proc->files, fd, file); __fd_install(proc->files, fd, file);
preempt_disable();
}
} }
/* /*