Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 9 Jan 2024 13:54:27 +0800 | Subject | Re: [PATCH v3 0/2] iommu/iova: Make the rcache depot properly flexible | From | Ethan Zhao <> |
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On 1/9/2024 1:35 AM, Robin Murphy wrote: > On 2023-12-28 12:23 pm, Ido Schimmel wrote: >> On Tue, Sep 12, 2023 at 05:28:04PM +0100, Robin Murphy wrote: >>> v2: >>> https://lore.kernel.org/linux-iommu/cover.1692641204.git.robin.murphy@arm.com/ >>> >>> Hi all, >>> >>> I hope this is good to go now, just fixed the locking (and threw >>> lockdep at it to confirm, which of course I should have done to begin >>> with...) and picked up tags. >> >> Hi, >> >> After pulling the v6.7 changes we started seeing the following memory >> leaks [1] of 'struct iova_magazine'. I'm not sure how to reproduce it, >> which is why I didn't perform bisection. However, looking at the >> mentioned code paths, they seem to have been changed in v6.7 as part of >> this patchset. I reverted both patches and didn't see any memory leaks >> when running a full regression (~10 hours), but I will repeat it to be >> sure. >> >> Any idea what could be the problem? > > Hmm, we've got what looks to be a set of magazines forming a plausible > depot list (or at least the tail end of one): > > ffff8881411f9000 -> ffff8881261c1000 > > ffff8881261c1000 -> ffff88812be26400 > > ffff88812be26400 -> ffff8188392ec000 > > ffff8188392ec000 -> ffff8881a5301000 > > ffff8881a5301000 -> NULL > > which I guess has somehow become detached from its rcache->depot > without being freed properly? However I'm struggling to see any > conceivable way that could happen which wouldn't already be more > severely broken in other ways as well (i.e. either general memory > corruption or someone somehow still trying to use the IOVA domain > while it's being torn down). > > Out of curiosity, does reverting just patch #2 alone make a > difference? And is your workload doing anything "interesting" in > relation to IOVA domain lifetimes, like creating and destroying SR-IOV > virtual functions, changing IOMMU domain types via sysfs, or using > that horrible vdpa thing, or are you seeing this purely from regular > driver DMA API usage?
There no lock held when free_iova_rcaches(), is it possible free_iova_rcaches() race with the delayed iova_depot_work_func() ?
I don't know why not call cancel_delayed_work_sync(&rcache->work); first in free_iova_rcaches() to avoid possible race.
Thanks,
Ethan
> > Thanks, > Robin. > >> >> Thanks >> >> [1] >> unreferenced object 0xffff8881a5301000 (size 1024): >> comm "softirq", pid 0, jiffies 4306297099 (age 462.991s) >> hex dump (first 32 bytes): >> 00 00 00 00 00 00 00 00 e7 7d 05 00 00 00 00 00 .........}...... >> 0f b4 05 00 00 00 00 00 b4 96 05 00 00 00 00 00 ................ >> backtrace: >> [<ffffffff819f5f08>] __kmem_cache_alloc_node+0x1e8/0x320 >> [<ffffffff818a239a>] kmalloc_trace+0x2a/0x60 >> [<ffffffff8231d31e>] free_iova_fast+0x28e/0x4e0 >> [<ffffffff82310860>] fq_ring_free_locked+0x1b0/0x310 >> [<ffffffff8231225d>] fq_flush_timeout+0x19d/0x2e0 >> [<ffffffff813e95ba>] call_timer_fn+0x19a/0x5c0 >> [<ffffffff813ea16b>] __run_timers+0x78b/0xb80 >> [<ffffffff813ea5bd>] run_timer_softirq+0x5d/0xd0 >> [<ffffffff82f1d915>] __do_softirq+0x205/0x8b5 >> >> unreferenced object 0xffff8881392ec000 (size 1024): >> comm "softirq", pid 0, jiffies 4306326731 (age 433.359s) >> hex dump (first 32 bytes): >> 00 10 30 a5 81 88 ff ff 50 ff 0f 00 00 00 00 00 ..0.....P....... >> f3 99 05 00 00 00 00 00 87 b7 05 00 00 00 00 00 ................ >> backtrace: >> [<ffffffff819f5f08>] __kmem_cache_alloc_node+0x1e8/0x320 >> [<ffffffff818a239a>] kmalloc_trace+0x2a/0x60 >> [<ffffffff8231d31e>] free_iova_fast+0x28e/0x4e0 >> [<ffffffff82310860>] fq_ring_free_locked+0x1b0/0x310 >> [<ffffffff8231225d>] fq_flush_timeout+0x19d/0x2e0 >> [<ffffffff813e95ba>] call_timer_fn+0x19a/0x5c0 >> [<ffffffff813ea16b>] __run_timers+0x78b/0xb80 >> [<ffffffff813ea5bd>] run_timer_softirq+0x5d/0xd0 >> [<ffffffff82f1d915>] __do_softirq+0x205/0x8b5 >> >> unreferenced object 0xffff8881411f9000 (size 1024): >> comm "softirq", pid 0, jiffies 4306708887 (age 51.459s) >> hex dump (first 32 bytes): >> 00 10 1c 26 81 88 ff ff 2c 96 05 00 00 00 00 00 ...&....,....... >> ac fe 0f 00 00 00 00 00 a6 fe 0f 00 00 00 00 00 ................ >> backtrace: >> [<ffffffff819f5f08>] __kmem_cache_alloc_node+0x1e8/0x320 >> [<ffffffff818a239a>] kmalloc_trace+0x2a/0x60 >> [<ffffffff8231d31e>] free_iova_fast+0x28e/0x4e0 >> [<ffffffff82310860>] fq_ring_free_locked+0x1b0/0x310 >> [<ffffffff8231225d>] fq_flush_timeout+0x19d/0x2e0 >> [<ffffffff813e95ba>] call_timer_fn+0x19a/0x5c0 >> [<ffffffff813ea16b>] __run_timers+0x78b/0xb80 >> [<ffffffff813ea5bd>] run_timer_softirq+0x5d/0xd0 >> [<ffffffff82f1d915>] __do_softirq+0x205/0x8b5 >> >> unreferenced object 0xffff88812be26400 (size 1024): >> comm "softirq", pid 0, jiffies 4306710027 (age 50.319s) >> hex dump (first 32 bytes): >> 00 c0 2e 39 81 88 ff ff 32 ab 05 00 00 00 00 00 ...9....2....... >> e3 ac 05 00 00 00 00 00 1f b6 05 00 00 00 00 00 ................ >> backtrace: >> [<ffffffff819f5f08>] __kmem_cache_alloc_node+0x1e8/0x320 >> [<ffffffff818a239a>] kmalloc_trace+0x2a/0x60 >> [<ffffffff8231d31e>] free_iova_fast+0x28e/0x4e0 >> [<ffffffff82310860>] fq_ring_free_locked+0x1b0/0x310 >> [<ffffffff8231225d>] fq_flush_timeout+0x19d/0x2e0 >> [<ffffffff813e95ba>] call_timer_fn+0x19a/0x5c0 >> [<ffffffff813ea16b>] __run_timers+0x78b/0xb80 >> [<ffffffff813ea5bd>] run_timer_softirq+0x5d/0xd0 >> [<ffffffff82f1d915>] __do_softirq+0x205/0x8b5 >> >> unreferenced object 0xffff8881261c1000 (size 1024): >> comm "softirq", pid 0, jiffies 4306711547 (age 48.799s) >> hex dump (first 32 bytes): >> 00 64 e2 2b 81 88 ff ff c0 7c 05 00 00 00 00 00 .d.+.....|...... >> 87 a5 05 00 00 00 00 00 0e 9a 05 00 00 00 00 00 ................ >> backtrace: >> [<ffffffff819f5f08>] __kmem_cache_alloc_node+0x1e8/0x320 >> [<ffffffff818a239a>] kmalloc_trace+0x2a/0x60 >> [<ffffffff8231d31e>] free_iova_fast+0x28e/0x4e0 >> [<ffffffff82310860>] fq_ring_free_locked+0x1b0/0x310 >> [<ffffffff8231225d>] fq_flush_timeout+0x19d/0x2e0 >> [<ffffffff813e95ba>] call_timer_fn+0x19a/0x5c0 >> [<ffffffff813ea16b>] __run_timers+0x78b/0xb80 >> [<ffffffff813ea5bd>] run_timer_softirq+0x5d/0xd0 >> [<ffffffff82f1d915>] __do_softirq+0x205/0x8b5 >
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