From 4d4712c1a4ac331574fb4542e4adcfd24fdb07d0 Mon Sep 17 00:00:00 2001 From: Imran Khan Date: Mon, 8 Nov 2021 18:33:09 -0800 Subject: lib, stackdepot: check stackdepot handle before accessing slabs Patch series "lib, stackdepot: check stackdepot handle before accessing slabs", v2. PATCH-1: Checks validity of a stackdepot handle before proceeding to access stackdepot slab/objects. PATCH-2: Adds a helper in stackdepot, to allow users to print stack entries just by specifying the stackdepot handle. It also changes such users to use this new interface. PATCH-3: Adds a helper in stackdepot, to allow users to print stack entries into buffers just by specifying the stackdepot handle and destination buffer. It also changes such users to use this new interface. This patch (of 3): stack_depot_save allocates slabs that will be used for storing objects in future.If this slab allocation fails we may get to a situation where space allocation for a new stack_record fails, causing stack_depot_save to return 0 as handle. If user of this handle ends up invoking stack_depot_fetch with this handle value, current implementation of stack_depot_fetch will end up using slab from wrong index. To avoid this check handle value at the beginning. Link: https://lkml.kernel.org/r/20210915175321.3472770-1-imran.f.khan@oracle.com Link: https://lkml.kernel.org/r/20210915014806.3206938-1-imran.f.khan@oracle.com Link: https://lkml.kernel.org/r/20210915014806.3206938-2-imran.f.khan@oracle.com Signed-off-by: Imran Khan Suggested-by: Vlastimil Babka Acked-by: Vlastimil Babka Cc: Geert Uytterhoeven Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Dmitry Vyukov Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Daniel Vetter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/stackdepot.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'lib') diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 09485dc5bd12..f034f095c627 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -231,6 +231,9 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, struct stack_record *stack; *entries = NULL; + if (!handle) + return 0; + if (parts.slabindex > depot_index) { WARN(1, "slab index %d out of bounds (%d) for stack id %08x\n", parts.slabindex, depot_index, handle); -- cgit v1.2.3