CVE-2023-53558

In the Linux kernel, the following vulnerability has been resolved:

rcu-tasks: Avoid prinfo() with spin lock in cblistinit_generic()

prinfo() is called with rtp->cbsgbllock spin lock locked. Because prinfo() calls printk() that might sleep, this will result in BUG like below:

[ 0.206455] cblistinitgeneric: Setting adjustable number of callback queues. [ 0.206463] [ 0.206464] ============================= [ 0.206464] [ BUG: Invalid wait context ] [ 0.206465] 5.19.0-00428-g9de1f9c8ca51 #5 Not tainted [ 0.206466] ----------------------------- [ 0.206466] swapper/0/1 is trying to lock: [ 0.206467] ffffffffa0167a58 (&portlockkey){....}-{3:3}, at: serial8250consolewrite+0x327/0x4a0 [ 0.206473] other info that might help us debug this: [ 0.206473] context-{5:5} [ 0.206474] 3 locks held by swapper/0/1: [ 0.206474] #0: ffffffff9eb597e0 (rcutasks.cbsgbllock){....}-{2:2}, at: cblistinitgeneric.constprop.0+0x14/0x1f0 [ 0.206478] #1: ffffffff9eb579c0 (consolelock){+.+.}-{0:0}, at: printk+0x63/0x7e [ 0.206482] #2: ffffffff9ea77780 (consoleowner){....}-{0:0}, at: consoleemitnextrecord.constprop.0+0x111/0x330 [ 0.206485] stack backtrace: [ 0.206486] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-00428-g9de1f9c8ca51 #5 [ 0.206488] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014 [ 0.206489] Call Trace: [ 0.206490] <TASK> [ 0.206491] dumpstack_lvl+0x6a/0x9f [ 0.206493] __lockacquire.cold+0x2d7/0x2fe [ 0.206496] ? stacktracesave+0x46/0x70 [ 0.206497] lockacquire+0xd1/0x2f0 [ 0.206499] ? serial8250consolewrite+0x327/0x4a0 [ 0.206500] ? __lockacquire+0x5c7/0x2720 [ 0.206502] rawspinlockirqsave+0x3d/0x90 [ 0.206504] ? serial8250consolewrite+0x327/0x4a0 [ 0.206506] serial8250consolewrite+0x327/0x4a0 [ 0.206508] consoleemitnextrecord.constprop.0+0x180/0x330 [ 0.206511] consoleunlock+0xf7/0x1f0 [ 0.206512] vprintkemit+0xf7/0x330 [ 0.206514] printk+0x63/0x7e [ 0.206516] cblistinitgeneric.constprop.0.cold+0x24/0x32 [ 0.206518] rcuinittasksgeneric+0x5/0xd9 [ 0.206522] kernelinitfreeable+0x15b/0x2a2 [ 0.206523] ? restinit+0x160/0x160 [ 0.206526] kernelinit+0x11/0x120 [ 0.206527] retfromfork+0x1f/0x30 [ 0.206530] </TASK> [ 0.207018] cblistinitgeneric: Setting shift to 1 and lim to 1.

This patch moves prinfo() so that it is called without rtp->cbsgbl_lock locked.