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Ola Jeppsson authored
It is possible that in between calling fastrpc_map_get() until map->fl->lock is taken in fastrpc_free_map(), another thread can call fastrpc_map_lookup() and get a reference to a map that is about to be deleted. Rewrite fastrpc_map_get() to only increase the reference count of a map if it's non-zero. Propagate this to callers so they can know if a map is about to be deleted. Fixes this warning: refcount_t: addition on 0; use-after-free. WARNING: CPU: 5 PID: 10100 at lib/refcount.c:25 refcount_warn_saturate ... Call trace: refcount_warn_saturate [fastrpc_map_get inlined] [fastrpc_map_lookup inlined] fastrpc_map_create fastrpc_internal_invoke fastrpc_device_ioctl __arm64_sys_ioctl invoke_syscall Fixes: c68cfb71 ("misc: fastrpc: Add support for context Invoke method") Cc: stable <stable@kernel.org> Signed-off-by:
Ola Jeppsson <ola@snap.com> Signed-off-by:
Abel Vesa <abel.vesa@linaro.org> Signed-off-by:
Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20221124174941.418450-4-srinivas.kandagatla@linaro.orgSigned-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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