Carlos Llamas 899f4160b1 binder: remove inaccurate mmap_assert_locked() ... Acquiring the mmap_lock during exit_mmap() was only added recently in v5.17 by commit 64591e8605 ("mm: protect free_pgtables with mmap_lock write lock in exit_mmap"). Soon after, asserts for holding this lock were added to the binder_alloc_set_vma() callback by the following two fix commits in mainline: commit b0cab80ecd ("android: binder: fix lockdep check on clearing vma") and commit a43cfc87ca ("android: binder: stop saving a pointer to the VMA"). These two fix commits were picked for stable trees including v5.15 were unfortunately the mmap_lock is not held during exit_mmap() yet and this unmet dependency leads to the following BUG report: ------------[ cut here ]------------ kernel BUG at include/linux/mmap_lock.h:156! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 3 PID: 437 Comm: binder Not tainted 5.15.68 #5 Hardware name: linux,dummy-virt (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : binder_alloc_vma_close+0x6c/0x70 lr : binder_alloc_vma_close+0x6c/0x70 sp : ffff800008687a70 x29: ffff800008687a70 x28: ffff02a7ccf89d00 x27: ffff02a7c92f99e8 x26: 000000000000012a x25: ffff02a7c6284740 x24: ffff02a7ccf8a360 x23: ffff02a7c92f9980 x22: 1ffff000010d0f6c x21: ffff02a7c92f99e8 x20: ffff02a7c92f9980 x19: ffff02a7d16b79a8 x18: 0000ffffe1702d20 x17: 3334373239343932 x16: 34206e6163735f74 x15: 78656e5f616d756e x14: 0a30303030303030 x13: 7366666f5f6e6163 x12: ffff60550564a12b x11: 1fffe0550564a12a x10: ffff60550564a12a x9 : dfff800000000000 x8 : ffff02a82b250957 x7 : 0000000000000001 x6 : ffff60550564a12a x5 : ffff02a82b250950 x4 : dfff800000000000 x3 : 0000000000000000 x2 : 0000000000000000 x1 : ffff02a7ccf89d00 x0 : 0000000000000374 Call trace: binder_alloc_vma_close+0x6c/0x70 binder_vma_close+0x38/0xf4 remove_vma+0x4c/0x94 exit_mmap+0x14c/0x2bc __mmput+0x70/0x19c mmput+0x68/0x80 do_exit+0x484/0xeb0 do_group_exit+0x5c/0x100 [...] This patch removes the inaccurate assert specifically from v5.15 since it's the only release with such issue. Note the mmap_lock is technically not needed here as the mm->mm_users has dropped to zero at this point. More context: https://lore.kernel.org/all/YxpQaio7xm3z9TUw@google.com/. Fixes: b0cab80ecd ("android: binder: fix lockdep check on clearing vma") Fixes: a43cfc87ca ("android: binder: stop saving a pointer to the VMA") Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: <stable@vger.kernel.org> # v5.15 Signed-off-by: Carlos Llamas <cmllamas@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-09-23 14:15:49 +02:00
..
binder_alloc_selftest.c	android: binder: stop saving a pointer to the VMA	2022-08-17 14:23:58 +02:00
binder_alloc.c	binder: remove inaccurate mmap_assert_locked()	2022-09-23 14:15:49 +02:00
binder_alloc.h	android: binder: stop saving a pointer to the VMA	2022-08-17 14:23:58 +02:00
binder_internal.h	binder: fix redefinition of seq_file attributes	2022-08-17 14:23:50 +02:00
binder_trace.h	binder: add trace at free transaction.	2020-11-11 08:20:44 +01:00
binder.c	binder: fix UAF of ref->proc caused by race condition	2022-09-08 12:28:04 +02:00
binderfs.c	binder: fix redefinition of seq_file attributes	2022-08-17 14:23:50 +02:00
Kconfig	treewide: replace '---help---' in Kconfig files with 'help'	2020-06-14 01:57:21 +09:00
Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00