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23 October 2021, 00:29:24 UTC
Revision 81b1a832d79749058863cffe2c0ed4ef40f6e6ec authored by Eric Dumazet on 24 November 2015, 19:39:54 UTC, committed by Linus Torvalds on 24 November 2015, 20:03:55 UTC 
pidns: fix NULL dereference in __task_pid_nr_ns()
 
I got a crash during a "perf top" session that was caused by a race in
__task_pid_nr_ns() :

pid_nr_ns() was inlined, but apparently compiler chose to read
task->pids[type].pid twice, and the pid->level dereference crashed
because we got a NULL pointer at the second read :

    if (pid && ns->level <= pid->level) { // CRASH

Just use RCU API properly to solve this race, and not worry about "perf
top" crashing hosts :(

get_task_pid() can benefit from same fix.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 4ce01c5
History
Tip revision: 81b1a832d79749058863cffe2c0ed4ef40f6e6ec authored by Eric Dumazet on 24 November 2015, 19:39:54 UTC
pidns: fix NULL dereference in __task_pid_nr_ns()
Tip revision: 81b1a83
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