Revision 7ff57e98fb78ad94edafbdc7435f2d745e9e6bb5 authored by Fabio M. De Francesco on 23 February 2022, 10:02:52 UTC, committed by Jakub Kicinski on 24 February 2022, 17:09:33 UTC
smc_pnetid_by_table_ib() uses read_lock() and then it calls smc_pnet_apply_ib() which, in turn, calls mutex_lock(&smc_ib_devices.mutex). read_lock() disables preemption. Therefore, the code acquires a mutex while in atomic context and it leads to a SAC bug. Fix this bug by replacing the rwlock with a mutex. Reported-and-tested-by: syzbot+4f322a6d84e991c38775@syzkaller.appspotmail.com Fixes: 64e28b52c7a6 ("net/smc: add pnet table namespace support") Confirmed-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Link: https://lore.kernel.org/r/20220223100252.22562-1-fmdefrancesco@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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lshrdi3.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* lib/lshrdi3.c
*/
#include <linux/module.h>
#include <linux/libgcc.h>
long long notrace __lshrdi3(long long u, word_type b)
{
DWunion uu, w;
word_type bm;
if (b == 0)
return u;
uu.ll = u;
bm = 32 - b;
if (bm <= 0) {
w.s.high = 0;
w.s.low = (unsigned int) uu.s.high >> -bm;
} else {
const unsigned int carries = (unsigned int) uu.s.high << bm;
w.s.high = (unsigned int) uu.s.high >> b;
w.s.low = ((unsigned int) uu.s.low >> b) | carries;
}
return w.ll;
}
EXPORT_SYMBOL(__lshrdi3);
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