In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Sync IRQ works before buffer destruction If something was written to the buffer just before destruction, it may be possible (maybe not in a real system, but it did happen in ARCH=um with time-travel) to destroy the ringbuffer before the IRQ work ran, leading this KASAN report (or a crash without KASAN): BUG: KASAN: slab-use-after-free in irqworkrunlist+0x11a/0x13a Read of size 8 at addr 000000006d640a48 by task swapper/0 CPU: 0 PID: 0 Comm: swapper Tainted: G W O 6.3.0-rc1 #7 Stack: 60c4f20f 0c203d48 41b58ab3 60f224fc 600477fa 60f35687 60c4f20f 601273dd 00000008 6101eb00 6101eab0 615be548 Call Trace: [<60047a58>] showstack+0x25e/0x282 [<60c609e0>] dumpstacklvl+0x96/0xfd [<60c50d4c>] printreport+0x1a7/0x5a8 [<603078d3>] kasanreport+0xc1/0xe9 [<60308950>] asanreportload8noabort+0x1b/0x1d [<60232844>] irqworkrunlist+0x11a/0x13a [<602328b4>] irqworktick+0x24/0x34 [<6017f9dc>] updateprocesstimes+0x162/0x196 [<6019f335>] tickschedhandle+0x1a4/0x1c3 [<6019fd9e>] tickschedtimer+0x79/0x10c [<601812b9>] _hrtimerrunqueues.constprop.0+0x425/0x695 [<60182913>] hrtimerinterrupt+0x16c/0x2c4 [<600486a3>] umtimer+0x164/0x183 [...] Allocated by task 411: savestacktrace+0x99/0xb5 stacktracesave+0x81/0x9b kasansavestack+0x2d/0x54 kasansettrack+0x34/0x3e kasansaveallocinfo+0x25/0x28 kasankmalloc+0x8b/0x97 _kasankmalloc+0x10/0x12 _kmalloc+0xb2/0xe8 loadelfphdrs+0xee/0x182 [...] The buggy address belongs to the object at 000000006d640800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 584 bytes inside of freed 1024-byte region [000000006d640800, 000000006d640c00) Add the appropriate irqworksync() so the work finishes before the buffers are destroyed. Prior to the commit in the Fixes tag below, there was only a single global IRQ work, so this issue didn't exist.