Danny van Heumen <danny@xxxxxxxxxxxxxxxxx> wrote: > In case of buggy firmware, brcmfmac may perform a hardware reset. If during > reset and subsequent probing an early failure occurs, a memory region is > accidentally double-freed. With hardened memory allocation enabled, this error > will be detected. > > - return early where appropriate to skip unnecessary clean-up. > - set '.freezer' pointer to NULL to prevent double-freeing under possible > other circumstances and to re-align result under various different > behaviors of memory allocation freeing. > - correctly claim host on func1 for disabling func2. > - after reset, do not initiate probing immediately, but rely on events. > > Given a firmware crash, function 'brcmf_sdio_bus_reset' is called. It calls > 'brcmf_sdiod_remove', then follows up with 'brcmf_sdiod_probe' to reinitialize > the hardware. If 'brcmf_sdiod_probe' fails to "set F1 blocksize", it exits > early, which includes calling 'brcmf_sdiod_remove'. In both cases > 'brcmf_sdiod_freezer_detach' is called to free allocated '.freezer', which > has not yet been re-allocated the second time. > > Stacktrace of (failing) hardware reset after firmware-crash: > > Code: b9402b82 8b0202c0 eb1a02df 54000041 (d4210000) > ret_from_fork+0x10/0x20 > kthread+0x154/0x160 > worker_thread+0x188/0x504 > process_one_work+0x1f4/0x490 > brcmf_core_bus_reset+0x34/0x44 [brcmfmac] > brcmf_sdio_bus_reset+0x68/0xc0 [brcmfmac] > brcmf_sdiod_probe+0x170/0x21c [brcmfmac] > brcmf_sdiod_remove+0x48/0xc0 [brcmfmac] > kfree+0x210/0x220 > __slab_free+0x58/0x40c > Call trace: > x2 : 0000000000000040 x1 : fffffc00002d2b80 x0 : ffff00000b4aee40 > x5 : ffff8000013fa728 x4 : 0000000000000001 x3 : ffff00000b4aee00 > x8 : ffff800009967ce0 x7 : ffff8000099bfce0 x6 : 00000006f8005d01 > x11: ffff8000099bfce0 x10: 00000000fffff000 x9 : ffff8000083401d0 > x14: 0000000000000000 x13: 657a69736b636f6c x12: 6220314620746573 > x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000030 > x20: fffffc00002d2ba0 x19: fffffc00002d2b80 x18: 0000000000000000 > x23: ffff00000b4aee00 x22: ffff00000b4aee00 x21: 0000000000000001 > x26: ffff00000b4aee00 x25: ffff0000f7753705 x24: 000000000001288a > x29: ffff80000a22bbf0 x28: ffff000000401200 x27: 000000008020001a > sp : ffff80000a22bbf0 > lr : kfree+0x210/0x220 > pc : __slab_free+0x58/0x40c > pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > Workqueue: events brcmf_core_bus_reset [brcmfmac] > Hardware name: Pine64 Pinebook Pro (DT) > CPU: 2 PID: 639 Comm: kworker/2:2 Tainted: G C 5.16.0-0.bpo.4-arm64 #1 Debian 5.16.12-1~bpo11+1 > nvmem_rockchip_efuse industrialio_triggered_buffer videodev snd_soc_core snd_pcm_dmaengine kfifo_buf snd_pcm io_domain mc industrialio mt> > Modules linked in: snd_seq_dummy snd_hrtimer snd_seq snd_seq_device nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reje> > Internal error: Oops - BUG: 0 [#1] SMP > kernel BUG at mm/slub.c:379! > > Signed-off-by: Danny van Heumen <danny@xxxxxxxxxxxxxxxxx> > Reviewed-by: Arend van Spriel <aspriel.gmail.com> > Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> Patch applied to wireless-next.git, thanks. cb774bd35318 wifi: brcmfmac: prevent double-free on hardware-reset -- https://patchwork.kernel.org/project/linux-wireless/patch/id1HN6qCMAirApBzTA6fT7ZFWBBGCJhULpflxQ7NT6cgCboVnn3RHpiOFjA9SbRqzBRFLk9ES0C4FNvO6fUQsNg7pqF6ZSNAYUo99nHy8PY=@dannyvanheumen.nl/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
