From: "Jason A. Donenfeld" Jason@zx2c4.com
stable inclusion from stable-v5.10.119 commit c47f215ab36d678e41dd3aa7710b542e79b0fed1 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6BB
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit da3951ebdcd1cb1d5c750e08cd05aee7b0c04d9a upstream.
When the interrupt handler does not have a valid cycle counter, it calls get_reg() to read a register from the irq stack, in round-robin. Currently it does this assuming that registers are 32-bit. This is _probably_ the case, and probably all platforms without cycle counters are in fact 32-bit platforms. But maybe not, and either way, it's not quite correct. This commit fixes that to deal with `unsigned long` rather than `u32`.
Cc: Theodore Ts'o tytso@mit.edu Reviewed-by: Dominik Brodowski linux@dominikbrodowski.net Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- drivers/char/random.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c index 6c36940e2c6e..35991d87d619 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1261,15 +1261,15 @@ int random_online_cpu(unsigned int cpu) } #endif
-static u32 get_reg(struct fast_pool *f, struct pt_regs *regs) +static unsigned long get_reg(struct fast_pool *f, struct pt_regs *regs) { - u32 *ptr = (u32 *)regs; + unsigned long *ptr = (unsigned long *)regs; unsigned int idx;
if (regs == NULL) return 0; idx = READ_ONCE(f->reg_idx); - if (idx >= sizeof(struct pt_regs) / sizeof(u32)) + if (idx >= sizeof(struct pt_regs) / sizeof(unsigned long)) idx = 0; ptr += idx++; WRITE_ONCE(f->reg_idx, idx);