On 08/16/2015 04:19 AM, Matan Barak wrote: > > > On 8/15/2015 5:14 PM, Doug Ledford wrote: >> On 08/06/2015 01:14 PM, Matan Barak wrote: >>> Separate the cleanup and release IB cache functions. >>> The cleanup function delete all GIDs and unregister the event channel, >>> while the release function frees all memory. The cleanup function is >>> called after all clients were removed (in the device un-registration >>> process). >>> >>> The release function is called after the device was put. >>> This is in order to avoid use-after-free errors if ther vendor >>> driver's teardown code uses IB cache. >>> >>> Squash-into: 'IB/core: Add RoCE GID table management' >>> Signed-off-by: Matan Barak <matanb@xxxxxxxxxxxx> >> >> I had originally used the v1 of this patch instead of v2. In order to >> make sure I didn't miss anything, I hand compared the final results of >> the v1 patch to what this patch would have created if I had used it. I >> found a few things worth nothing, comments inline below. >> >>> @@ -903,20 +924,28 @@ int ib_cache_setup_one(struct ib_device *device) >>> (rdma_end_port(device) - >>> rdma_start_port(device) + 1), >>> GFP_KERNEL); >>> - err = gid_table_setup_one(device); >>> - >>> - if (!device->cache.pkey_cache || !device->cache.gid_cache || >>> + if (!device->cache.pkey_cache || >>> !device->cache.lmc_cache) { >>> printk(KERN_WARNING "Couldn't allocate cache " >>> "for %s\n", device->name); >>> - err = -ENOMEM; >>> - goto err; >>> + /* pkey_cache is freed here because we later access it's >>> + * elements. >>> + */ >>> + kfree(device->cache.pkey_cache); >>> + device->cache.pkey_cache = NULL; >>> + return -ENOMEM; >> >> This function is unnecessarily convoluted IMO. A simple change to using >> kzalloc() for the pkey_cache alloc eliminates part of the issue. As a >> result, I fixed this function up to be different than either patch. >> Please look over my results and make sure you agree with my changes. >> >>> } >>> >>> - for (p = 0; p <= rdma_end_port(device) - >>> rdma_start_port(device); ++p) { >>> + for (p = 0; p <= rdma_end_port(device) - >>> rdma_start_port(device); ++p) >>> device->cache.pkey_cache[p] = NULL; >> >> For instance this goes away entirely by using kzalloc(). >> >> The rest looked ok. I have to fixup the ordering changes between sysfs >> and cache to make the v1 patch match the v2 patch. >> >> > > Thanks for the squashing and re-ordering these patches. > I think you're missing if (device->cache.pkey_cache) over the for pkey > free loop in ib_cache_release_one. I think you're right, but I think that particular issue exists in both versions of the code (mine and yours). In particular, a failure during ib_register_device should result in a call to ib_dealloc_device which will result in a call to ib_cache_release_one, which will happen whether ib_cache_setup_one returns an error or not. So, ib_cache_release_one must check pkey_cache before releasing the ports because it can't assume the original setup succeeded. > Otherwise, the allocation of > device->cache.pkey_cache might has failed and you dereference an invalid > address device->cache.pkey_cache[p]. > > In addition, ib_device_release calls ib_cache_release_one with device > instead of dev (which has the wrong type). > ib_register_device calls ib_cache_clean_one that I can't really find :) Both of these turned up in compile tests. I've since resolved them. Hand merge issues ;-) -- Doug Ledford <dledford@xxxxxxxxxx> GPG KeyID: 0E572FDD
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