[RFC PATCH for 4.21 03/16] mm: Replace BUG_ON() by WARN_ON() in vm_unmap_ram()

[Mathieu Desnoyers]

It is encouraged to warn and return rather than use BUG_ON() when
the condition can be recovered from in ways that are more graceful than
halting the whole system.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
Suggested-by: Steven Rostedt <rost...@goodmis.org>
CC: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
CC: Matthew Wilcox <mawil...@microsoft.com>
CC: "Paul E. McKenney" <paul...@linux.vnet.ibm.com>
CC: Peter Zijlstra <pet...@infradead.org>
CC: Paul Turner <p...@google.com>
CC: Thomas Gleixner <t...@linutronix.de>
CC: Andy Lutomirski <l...@amacapital.net>
CC: Andi Kleen <a...@firstfloor.org>
CC: Dave Watson <davejwat...@fb.com>
CC: Chris Lameter <c...@linux.com>
CC: Ingo Molnar <mi...@redhat.com>
CC: "H. Peter Anvin" <h...@zytor.com>
CC: Ben Maurer <bmau...@fb.com>
CC: Steven Rostedt <rost...@goodmis.org>
CC: Josh Triplett <j...@joshtriplett.org>
CC: Linus Torvalds <torva...@linux-foundation.org>
CC: Andrew Morton <a...@linux-foundation.org>
CC: Russell King <li...@arm.linux.org.uk>
CC: Catalin Marinas <catalin.mari...@arm.com>
CC: Will Deacon <will.dea...@arm.com>
CC: Michael Kerrisk <mtk.manpa...@gmail.com>
CC: Boqun Feng <boqun.f...@gmail.com>
---
 mm/vmalloc.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a728fc492557..a236bac872f0 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1123,10 +1123,11 @@ void vm_unmap_ram(const void *mem, unsigned int count)
        struct vmap_area *va;
 
        might_sleep();
-       BUG_ON(!addr);
-       BUG_ON(addr < VMALLOC_START);
-       BUG_ON(addr > VMALLOC_END);
-       BUG_ON(!PAGE_ALIGNED(addr));
+       if (WARN_ON(!addr) ||
+           WARN_ON(addr < VMALLOC_START) ||
+           WARN_ON(addr > VMALLOC_END) ||
+           WARN_ON(!PAGE_ALIGNED(addr)))
+               return;
 
        if (likely(count <= VMAP_MAX_ALLOC)) {
                debug_check_no_locks_freed(mem, size);
@@ -1135,7 +1136,8 @@ void vm_unmap_ram(const void *mem, unsigned int count)
        }
 
        va = find_vmap_area(addr);
-       BUG_ON(!va);
+       if (WARN_ON(!va))
+               return;
        debug_check_no_locks_freed((void *)va->va_start,
                                    (va->va_end - va->va_start));
        free_unmap_vmap_area(va);
-- 
2.11.0